Stage Hormone Receptor Positive Breast Research Articles

Long-Term Adherence to Adjuvant Endocrine Therapy Following Various Radiotherapy Modalities in Early Stage Hormone Receptor Positive Breast Cancer

IntroductionWe compared the rates of long-term adjuvant endocrine therapy (AET) adherence after various radiation therapy (RT) modalities among patients with early stage breast cancer. Materials and MethodsMedical records from patients with stage 0, I, or IIA (tumors ≤3 cm), hormone receptor (HR) positive breast cancer that received adjuvant radiation therapy (RT) from 2013 to 2015 at a single institution were retrospectively reviewed. All patients received breast conserving surgery (BCS) followed by adjuvant RT via one of the following modalities: whole breast radiotherapy (WBI), partial breast irradiation (PBI) with either external beam radiation therapy (EBRT) or fractionated intracavitary high-dose rate (HDR) brachytherapy, or single fraction HDR-brachytherapy intraoperative-radiation therapy (IORT). ResultsOne hundred fourteen patients were reviewed. Thirty patients received WBI, 41 PBI, and 43 IORT with a median follow up of 64.2, 72.0, and 58.6 months, respectively. For the entire cohort, AET adherence was approximately 64% at 2 years and 56% at 5 years. Among patients in the IORT clinical trial, adherence to AET was approximately 51% at 2 years and 40% at 5 years. After controlling for additional factors, DCIS histology (vs invasive disease) and IORT (compared to other radiation modalities) were associated with decreased endocrine therapy adherence (P < 0.05). ConclusionDCIS histology and receipt of IORT were associated with lower rates of adherence to AET at 5 years. Our findings suggest that examination of the efficacy of RT interventions such as PBI and IORT in patients who do not receive AET is warranted.

The Futility of Futility Analyses in Adjuvant Trials in Hormone Receptor-Positive Breast Cancer.

An interim analysis is commonly used in phase III superiority trials to compare treatment arms, with the goal of terminating exposure of patients to ineffective or unsafe drugs or to identify highly effective therapies for earlier public disclosure. Traditionally, interim analyses have been designed to identify early evidence of extremely large benefit of the experimental approach, potentially leading to early dissemination of effective treatments. Increasingly, interim analysis has also involved analysis of futility, which may lead to early termination of a trial that will not yield additional useful information. This presents an important challenge in early stage hormone receptor–positive breast cancer, where recurrence often occurs late, with a steady annual event rate up to 20 years. Early analysis of events may miss late treatment effects that can be observed only with longer follow-up. We discuss approaches to futility analysis in adjuvant clinical trials in hormone receptor–positive breast cancer, the role of the Data Safety Monitoring Committee in such analyses, considerations of the potential harms vs benefits of treatment, and the risks of continuing vs early termination of a trial.

Abstract GS2-04: Aromatase inhibitors versus tamoxifen in pre-menopausal women with estrogen receptor positive early stage breast cancer treated with ovarian suppression: A patient level meta-analysis of 7,030 women in four randomised trials

Abstract Background: For women with early stage hormone receptor positive breast cancer, adjuvant treatment with tamoxifen reduces their 15-year risk of death from breast cancer by about one third. Aromatase inhibitors (AIs) are even more effective than tamoxifen in post-menopausal women but, used alone, are ineffective in pre-menopausal women due to compensatory ovarian oestrogen production. Several trials have assessed whether, if administered with ovarian suppression, AIs may also be more effective than tamoxifen at preventing breast cancer recurrence in premenopausal women but trial results have been inconsistent. Methods: Individual patient data were available from four randomised controlled trials, including 7,030 pre-menopausal women with estrogen receptor positive (ER+) breast cancer. All women received ovarian suppression or ablation and were randomised to receive either an AI or tamoxifen for 3 years (in ABCSG XII) or 5 years in other trials (SOFT, TEXT and HOBOE). Primary outcomes for the meta-analysis were time to invasive breast cancer recurrence (distant, loco-regional, or new contralateral breast primary) and breast cancer mortality. Log-rank analyses were used to estimate first-event rate ratios (RR) and their confidence intervals (CIs). Results: Overall, the annual rate of recurrence averaged 21% lower (RR 0.79, 95% 0.69-0.90, p=0.0005) for women allocated AI compared to tamoxifen. The main benefit from AI was seen in years 0-4 (RR 0.68, 99% CI 0.58-0.80), during the period when treatments differed, with no further benefit, or loss of benefit, in years 5-9 (RR 0.98, 99% 0.73-1.32), and as yet limited follow up data available beyond year 10. The 5-year absolute risk of breast cancer recurrence was 3.2% lower in the AI group than the tamoxifen group (6.9% vs 10.1%, p=0.0005). Although distant recurrence was reduced with AI (RR 0.83, 95% CI 0.71-0.97, p=0.02), there was no difference in breast cancer mortality although longer follow up is needed to assess effects on mortality reliably. The proportional reduction in recurrence during the period when treatments differed did not vary by age, BMI, or by tumour size, tumour grade, histological subtype, or presence and absence of chemotherapy. In contrast to the findings of the meta-analysis of AI vs tamoxifen in postmenopausal women, AI appeared ineffective in N4+ disease (RR=0.49 in N0, RR=0.56 in N1-3, RR=1.03 in N4+; p for trend =0.0009). The only other apparent heterogeneity was between the four trial results (p=0.03), and between HER2-negative and positive disease (p=0.05), which may be chance findings given the borderline statistical significance. There were more bone fractures in women receiving AI (5.0% AI vs 3.8% Tam, p=0.02). Among these younger women, few non-breast cancer deaths occurred: 0.9% AI vs 0.7% Tam (RR 1.30, 95% CI 0.75-2.25), and the incidence of endometrial cancer was low (0.2% AI vs 0.3% tamoxifen, p=0.14). Conclusion: Using an AI rather than tamoxifen, in premenopausal women receiving ovarian suppression, reduces the risk of breast cancer recurrence by about 20%. If the surprising lack of benefit in N4+ disease is a chance finding, then the absolute benefits will be larger for women at a higher absolute risk of recurrence. Citation Format: Rosie Bradley, Jeremy Braybrooke, Richard Gray, Robert K Hills, Zulian Lui, Hongchao Pan, Richard Peto, Jonas Bergh, Sandra M Swain, Prudence Francis, Michael Gnant, Francesco Perrone, Meredith M Regan. Aromatase inhibitors versus tamoxifen in pre-menopausal women with estrogen receptor positive early stage breast cancer treated with ovarian suppression: A patient level meta-analysis of 7,030 women in four randomised trials [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr GS2-04.

Survival outcome and treatment tolerability for postmenopausal females with early stage hormone receptor positive breast cancer treated with different adjuvant hormonal lines (TAM vs. AI vs. switching strategy) for 5 years

Abstract Background The standard adjuvant endocrine treatment for postmenopausal female patients with hormone receptor positive early breast cancer was 5 years of tamoxifen, but recurrence and side effects restrict its usefulness. The aromatase inhibitor (anastrozole or exemestane or letrozole) was compared with tamoxifen for 5 years or started after completing 2-3 years of tamoxifen in postmenopausal female patients diagnosed with early breast cancer at "Ain Shams University Hospitals" Objective The aim of the study was to measure survival outcome and treatment tolerability for postmenopausal females with Hormone Receptor Positive early breast cancer who received adjuvant hormonal treatment with tamoxifen [TAM] only for 5 years versus those who received adjuvant hormonal treatment with tamoxifen [TAM] for 2 years switching to aromatase inhibitors [AI] in the sequential 3 years versus those who received adjuvant hormonal treatment with aromatase inhibitors [AI] solely for 5 years. Patients and methods This study included 100 postmenopausal women with early breast cancer who presented at the Clinical Oncology Department, Ain Shams University, in the interval from January 2010 until December 2015. Conclusion Similar disease free survival and overall survival were observed among the three studied groups. Switching tamoxifen to aromatase inhibitors provides better tolerability in terms of endometrial thickness when compared to 5 years of tamoxifen monotherapy. Patients who administer aromatase inhibitor included in the switching strategy experience less osteoporosis and less generalized bone pain compared to upfront aromatase inhibitor to 5 years. There was a significant improvement of disease free survival (DFS) in human epidermal growth factor receptor 2 (HER 2) negative patients receiving any adjuvant hormonal treatment line for five years in comparison to HER 2 positive patients receiving the same adjuvant hormonal treatment for five years.

Association between estrogen receptor status and Oncotype Dx breast recurrence score.

e12519 Background: The 21 gene assay Oncotype Dx Breast Recurrence Score (RS) is currently the standard of care to determine if adjuvant chemotherapy is needed in early stage node negative, hormone receptor positive, HER-2 negative breast cancer. In current American society of clinical oncology (ASCO) guidelines there is little or no benefit of adjuvant chemotherapy in patients older than 50 years whose tumors have Oncotype DX RS &lt;26, and for patients 50 years or less whose tumors have Oncotype DX RS &lt;16. We sought to evaluate the percentage of estrogen receptor (ER) expression as a surrogate measure of determining adjuvant chemotherapy by examining the relationship between ER expression and RS. Methods: We identified 301 patients from years 2015 to 2019 from our cancer registry with early stage hormone receptor positive breast cancer and had oncotype DX testing performed. We divided patients into three groups: Group 1 (ERG1) with ER &lt;10%; Group 2 (ERG2) with ER 10-49%; and Group 3 (ERG3) with ER equal or &gt;50%. We also collected information on tumor size (cm), tumor grade, Nottingham score, and ki-67 percentage. A sub-group analysis was performed for patients &lt; 50 years age (n=30). We compared all continuous variables across ER groups using the Kruskal-Wallis rank test and individual between group comparisons using the Wilcoxon rank sum test. All statistical tests performed utilized a two-tailed p value of &lt;0.05 with the Bonferroni correction for multiple comparisons. Results: Among 301 patients with early stage hormone receptor positive breast cancer, 89.1% were ductal, 7.9% lobular, and 2.9% mixed histology. Median age was 68, 58 and 66 for ERG1, ERG2, and ERG3, respectively (p = 0.41). Median RS was 36 (ERG1), 23 (ERG2), and 16 (ERG3) (p = 0.78 for ERG1 vs. ERG2; p = 0.01 for ERG1 vs. ERG3). As expected, tumor grade, tumor size, and Nottingham score decreased significantly from ERG1 to ERG3. For patients &lt;50 years, median age was 44, 46 and 45 for ERG1, ERG2, and ERG3, respectively (p = 0.75). Median RS was 10 (ERG1), 24 (ERG2) and 18 (ERG3) (p = 0.04 for ERG1 vs. ERG2; p = 0.17 for ERG1 vs. ERG3). Conclusions: We found a significant association between estrogen receptor levels and Oncotype Dx recurrence score (RS) in patients with early stage hormone receptor positive breast cancer patients. Further studies are needed to determine the predictive ability of hormone receptor levels on the outcomes of patients treated for early stage hormone receptor positive breast cancer.

Abstract SS2-05: Emerging from COVID-19 pandemic: Provider perspective on use of neoadjuvant endocrine therapy (NET) in early stage hormone receptor positive breast cancer

Introduction During the coronavirus 2019 (COVID-19) pandemic in USA, NET use has been recommended to allowsafe deferral of surgical treatment in early stage, estrogen receptor positive breast cancer (ER+BC) In suchcircumstances, after NET use there is limited guidance on locoregional treatment, especially with management of the axilla We aimed to evaluate patterns of care in early stage ER+BC during the first several months of theCOVID-19 pandemic Method A cross-sectional, 30-item survey was developed using a standardized surveydevelopment framework The survey was administered May 8 - June 12, 2020 to a convenience sample of medicaloncologists (MO), radiation oncologists (RO), and surgeons (SO) - breast committee members of two nationalcooperative groups (Alliance and SWOG) with additional participation through chain referrals Providers were presented with general questions on NET use before and during the pandemic They were asked their propensity foromitting axillary lymph node dissection (ALND) after NET if 1 micrometastatic node is found on sentinel lymph nodebiopsy, based on duration of NET Results 114 providers from 29 US states completed the survey - 42 (37%) MO, 14(12%) RO, and 58 (51%) SO, the majority (N=73/96, 76%) with practices dedicated ≥ 75% to BC, at NCI designatedcomprehensive cancer centers 52% (N=48/94) and in large cities (N=49/94, 52%) Prior to COVID-19, most rarely(N=49/107, 46%) or sometimes (N=36, 33%) used NET for early stage ER+BC Nearly half were willing to delay surgery up to 2 months (46%) and 3 months (21%) without use of NET (Table 1, p<0 05) Most providers wouldperform a genomic assay on the biopsy specimen on all or select patients prior to NET initiation, more frequently byMO compared to RO and SO (90% vs 75% and 60%, p<0 05) The most preferred regimen was tamoxifen (withoutovarian suppression) for premenopausal patients and aromatase inhibitor for postmenopausal patients Mostplanned to use NET for as little time as possible until surgery could proceed When stratified by specialty, more MOstated they would vary the duration of therapy based on patient's risk of cancer progression Most providersrecommended omitting ALND after 1, 2, or 3 months of NET (1 month N=56/93, 60%;2 months N=54/92, 59%;3months N=48/90, 53%) With longer duration of therapy, the propensity for omitting ALND decreased (definitely omitafter 6 months N=25/91, 27%;probably omit after 6 months N=38/91, 42%;definitely omit after 1 year N=26/92,28%;probably omit after 1 year N=29/92, 32%) Omitting ALND was not associated with provider's years in practice,percent of practice dedicated to BC, practice type or setting, participation in multidisciplinary tumor board, or numberof COVID-19 cases in the provider's practicing state ConclusionMost providers changed their management of early stage ER+BC during the COVID-19 pandemic by utilizing NET until surgery could proceed As the duration of NET extended, more providers favored ALND in low volume axillary metastatic disease in early stage ER+BC Additional data to inform the care on post-NET locoregional management is needed

Abstract PS4-47: Multi-country clinical validation of can assist breast in Europe indicates robustness of the test

Abstract Background: CanAssist Breast (CAB) is a prognostic test for early stage hormone receptor positive breast cancer patients, that predicts risk of distant recurrence in five years post-diagnosis. Its support vector machine-based algorithm utilizes immunohistochemistry profiles of five biomarkers involved in tumor biology (CD44, ABCC4, ABCC11, N-Cadherin and pan-Cadherin) and three clinical parameters (tumor size, grade, and node status) to categorize patients into low- or high-risk of distant recurrence. CAB was developed on Indian patients, and has been validated in Indian and US patients. The current study presents first ever multi-country, blinded, retrospective validation of CAB. Methods: A total of 669 patients’ breast tumors from Austria (n=327), Spain (n=292) and Italy (n=50) diagnosed 5-10 years ago along with known clinical parameters were included. CAB was performed on the formalin fixed tumor samples using Roche’s automated immunohistochemistry platform at OncoStem’s CAP accredited reference laboratory in India. CAB risk predictions were matched with the clinical outcomes by the respective hospitals. Distant Metastasis Free Survival (DMFS), negative predictive value (NPV) and Hazard Ratio (HR) were computed from Kaplan-Meier survival curves using MedCalc software. Results: The median age of the cohort was 60 years (range: 28-92 years), with only 28% of patients aged &amp;lt; 50 years. The cohort had equal proportions of stage I and stage II patients and 19% of patients with poorly differentiated tumors (G3). Amongst stage II patients 57% had three nodes positive (N1) disease. Total cohort had of 72% N0 patients and 28% N1 patients. The DMFS of this cohort was 95% in low-risk versus 82% in high-risk category (p &amp;lt; 0.0001). The recurrence rate was 5% in low-risk category as against 18% in high-risk category. The risk stratification of patients treated with endocrine therapy alone (68%) was similar to chemo-endocrine therapy (32%) treated patients, both had 95% DMFS in low-risk category. Subtle differences in the NPV was observed across different European patient cohorts: Spain-96%, Italy-100%, Austria-93%. The performance of CAB in European cohort was comparable to the mixed validation cohort of ~1100 patients from India and US, with identical DMFS of 95% in the low-risk category. In a sub-cohort of T1N0 patients (50%), the DMFS in low-risk group was still higher at 97%. In the multivariate Cox proportional hazards model, CanAssist Breast risk score had the highest and significant hazard ratio of 2.9 (p=0.0013, CI: 1.5-5.5) over clinical parameters (node, grade, tumor size), age and type of therapy (endocrine vs. chemo-endocrine). Conclusion: The current study demonstrates the robustness of risk prediction by CAB in an European cohort of diverse nationalities and ethnicities. Similar accuracy of CAB in the Indian and European cohort emphasizes that CAB based risk predictions are driven by tumor biology and are independent of conventional prognostic factors. Citation Format: Somashekhar SP, Aparna Gunda, Chandra Prakash V Serkad, Aditya K Sengupta, Patricia Gomez, Cristina Saura, Vicente Peg, Jose Jimenez, Susanne Sprung, Heidelinde Fiegl, Christine Brunner, Daniel Egle, Manjiri M Bakre. Multi-country clinical validation of can assist breast in Europe indicates robustness of the test [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS4-47.

Abstract P6-04-23: HER2 up-regulation with neoadjuvant endocrine therapy in patients with hormone receptor-positive, HER2-negative breast cancer

Abstract Background Endocrine therapy provides significant disease-free survival (DFS) and overall survival (OS) benefit to patients with early stage hormone receptor positive (HR+) HER2 negative breast cancer. However, metastatic recurrence of endocrine-resistant disease develops in 20-25% of patients and remains a major cause of breast cancer mortality. Several mechanisms play a role in the progression and development of endocrine resistance. Understanding and characterizing the underlying molecular features of resistance for more accurate response prediction and optimal clinical management is of the utmost importance. Methods We designed an interventional study to assess tumor responses, changes in tumor proliferation and molecular biomarkers in early stage HR+ HER2- clinical node-negative breast cancer patients treated with neoadjuvant endocrine therapy for 4 weeks. The primary objective is to assess changes in HER protein expression (HER1-4) with neoadjuvant endocrine therapy; secondary objectives assess other molecular changes such as therapy-resistant CK5+ progenitor cells, iron-related proteins, Bruton’s tyrosine kinase (BTK), PD-L1, PD-L2 protein expressions, association with Ki-67 and tumor responses. Interim data on changes in HER2 protein in the first 16 patients is reported here. Optimized protocols for immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) were used to assess HER2 status in the pre and post treatment tumor specimens. This is an ongoing investigator-initiated clinical trial funded by Rock River Foundation and the Medical College of Wisconsin Cancer Center (NCT03219476). Results Median age at diagnosis was 65 (42-81) and median BMI was 28.3 (19.3-50.1). Most patients were post-menopausal (81%). Median tumor size clinically was 1.3 cm (0.5-7.7). Most tumors were low (50%) or intermediate (37.5%) grade and invasive ductal histology (62.5%). Median tumor size at surgery was 1.1 cm (0-3.9). One patient had a complete pathologic response (pCR) at surgery. Four patients had pN1 (1 lymph node involved) and one patient had pN1mic disease at surgery. There was no significant change in ER-positivity between pre and post-treatment specimens. However, a significant decrease in PR-positivity was seen in post-treatment tumors consistent with functional ER pathway disruption. On HER2 protein assessment by IHC, most patients had IHC 0 (37.5%) or IHC 1+ (56%) at diagnosis. Up-regulation in HER2 protein was seen in post-treatment tumors with 36% (n=5) IHC 2+, with one case showing Her2 gene amplification by FISH. Conclusions HER2 was up regulated in 36% of tumors after short-term neoadjuvant endocrine treatment in patients with early stage HR+ HER2- breast cancer. Short-term neoadjuvant endocrine treatment holds potential for identifying emergent endocrine resistance mechanisms and pathways. Targeted therapy with HER2-directed antibodies for such HER2 up-regulated tumors after neoadjuvant endocrine treatment may benefit patients upon disease recurrence or possibly as adjuvant combination therapy in patients with high risk of recurrence. Citation Format: Lubna N Chaudhary, Julie Jorns, MaryBeth Gonyo, Amanda Kong, Amy R Peck, Yunguang Sun, Carmen Bergom, Anjishnu Banarjee, Christopher Chitambar, Hallgeir Rui. HER2 up-regulation with neoadjuvant endocrine therapy in patients with hormone receptor-positive, HER2-negative breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-04-23.

Abstract 2428: New school health care: Utilizing technology in the treatment and support of women with breast cancer in the ambulatory setting

Abstract Background Adjuvant endocrine therapies (AETs) (e.g. tamoxifen and aromatase inhibitors (AIs) are almost always prescribed to early stage breast cancer (BrCa) patients as AETs have been shown to reduce risk of recurrence and mortality for women with hormone receptor-positive early stage breast cancer. Despite proven efficacy and patient education efforts, AET adherence is suboptimal. Most patients report symptom burden as the most common cause for non-adherence. We conducted focus groups among this patient population to aid in the refinement of a communication app for patients to report symptoms to their healthcare team and receive tailored feedback messages. The app aims to improve AET adherence, symptom management, and quality of life. Method Four focus groups (N=28), stratified by race (Black and White) and patient length of time on AET ( &amp;lt; 6 months AET use or &amp;gt; 6 months AET use), were conducted in Memphis, Tennessee. The focus groups were audiotaped, transcribed, and analyzed to identify key themes. Results Participants indicated they would be open to utilizing technology throughout their cancer treatment. The app was viewed as a conduit in the exchange of information between the patient and their healthcare team. Even patients who typically did not use or “like” technology thought the messages and symptom management information would be beneficial. Reporting symptoms through the app and then receiving a phone call from their healthcare team to respond to those symptoms was viewed as the most beneficial component to the patients. One participant stated how she could see the benefit of the symptom reporting feature when first initiating AET therapy: “There were times when I wanted to go tell my doctor, “STOP THIS MEDICINE RIGHT NOW, find me something else to do, find something else besides this because this stuff is not working for me.” In regards to the tailored feedback messaging through the app, participant stated, “I like the one that says, ‘Take meds regularly is an effective way to prevent cancer from coming back,’ because for me that is the only reason why I take it SOME days just to make sure that it doesn’t come back because I HATE the stuff.” Conclusions Early stage hormone receptor positive breast cancer patients may benefit from utilizing technology in the management of their care. The use of a communication app with tailored feedback messaging has the potential to increase medication adherence, improve symptom management and quality of life, improve the provider- patient relationship, and ultimately reduce mortality. As healthcare shifts toward focusing on patient-centered care and preparing patients to manage their care at home, apps like the one examined in the current study may play a vital role in helping these and other patient populations. Citation Format: Tameka N. Jones, Andrew J. Paladino, Gregory A. Vidal, Rebecca Krukowski, J. Carolyn Graff, Ryan Blue, Ilana Graetz, Lee Schwartzberg, Mehmet Kocak, Janeane Anderson. New school health care: Utilizing technology in the treatment and support of women with breast cancer in the ambulatory setting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2428.

Utility of the Breast Cancer Index (BCI) in the clinical practice.

e14723 Background: Extended endocrine therapy (EET) greater than 5 years in early stage hormone receptor positive (HR+) breast cancer (BC) patients has shown benefit. However, EET is associated with side effects and there is no validated assay to determine which group of patients would derive benefit. Breast Cancer Index (BCI) is a validated bio-marker test that incorporates 2 distinct genomic assays and is prognostic/predictive. The objective of this study is to assess patient characteristics, pathologic features and patient preferences with regards to extending endocrine therapy after reviewing the BCI results. Methods: We performed a retrospective chart review on early stage HR+ BC patients from Jan, 2016 to Jan, 2017 at the University of Vermont Medical Center. We identified 25 cases on whom BCI was submitted. Results: Median age was 68 years. Majority of the patients were stage IA (64%). 56% of the tumors were moderately differentiated. All patients were ER +ve and 12% were HER2+. Median tumor size was 1.4 cm (0.3-4). 76% had poor tolerance to the ET and preferred the test to be sent. In LN-patients, BCI identified 42% as high risk and 52% as low risk for late recurrence and 32% who derive high benefit from EET. In LN+ patients, BCI identified 75% as high risk for late recurrence and 25% as low risk for late recurrence. 40% of the entire group were identified to highly benefit from EET (70% agreed to continue ET and 30% denied due to side effects). Conclusions: BCI is a reasonable test to consider in early stage HR+ BC, especially in patients with poor tolerance to ET. This test might aid in decision making with tolerability/compliance challenges to EET. [Table: see text]

Abstract P4-08-12: Comparative analyses of the prognostic value of oncotype and mammaprint using the National Cancer Database

Abstract INTRODUCTION: Majority of the approximately 40,610 deaths from metastatic breast cancer in the US each year occur in women with hormone receptor positive breast cancer who recur after treatment for early stage disease. Genomic analysis is increasingly used to personalize breast cancer treatment for women with early breast cancer resulting in AJCC 8 modification of TNM staging. The 70-gene Mammaprint was developed using both ER- and ER+ breast tissue samples, while the 21-gene Oncotype DX (ODX) assay was developed using only ER+ breast tissue. Previous studies found that the two genomic assays gave discordant testing results. OBJECTIVE: To compare the performance of Mammaprint and Oncotype DX in assigning prognosis in early stage hormone receptor positive breast cancer. METHOD: A retrospective cohort of women diagnosed with early stage, hormone receptor positive breast cancer who received ODX or Mammaprint was established using the National Cancer Data Base (NCDB), 2010-2014. Using the propensity score matching method, we defined two groups of patients with similar clinical and demographic characteristics; one group received ODX and another received Mammaprint. The groups were matched by clinicopathologic and demographic factors. We examined the association between ODX or Mammaprint and overall survival using Log-rank test and Cox models in the two groups separately. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated as strength of association. The prognostic values were evaluated using c-index (i.e. area under ROC curve). RESULTS: Of 320,276 eligible patients with breast cancer, 41.5% received ODX and 1.3% received Mammaprint testing. The use of ODX increased from 34.3% in 2010 to 45.2% in 2014, while the use of Mammaprint increased from 0.5% in 2010 to 2.0% in 2014. After propensity score matching, we identified 3319 patients who received ODX and matched to 3319 patients who received Mammaprint. Compared to patients with a low risk Mammaprint score (n=1915), patients with a high risk Mammaprint score (n=1404) had 4.53-fold increased risk of dying (95% CI 2.79-7.36). The c-index for Mammaprint was 0.683. Relative to patients with a low ODX recurrence score (n=1927), the HR for intermediate ODX score was 1.23 (95% CI 0.76-1.98) and the HR for high ODX score was 3.62 (95% CI 2.21-5.94). The c-index for ODX was 0.601. In patients with ODX testing, 28.2% received chemotherapy. In patients with Mammaprint testing, 42.4% received chemotherapy. Based on MINDACT's modification of Adjuvant!Online, 49.2% patients were assigned to the clinical high risk group, including 22.3% to the clinical high risk/genomic low risk (C-high/G-low) subgroup and 26.9% to the C-high/G-high subgroup. The percentage of patients receiving chemotherapy with C-low/G-low, C-low/G-high, C-high/G-low, and C-high/G-high were 4.3%, 70.4%, 32.2%, and 84.9%, respectively. CONCLUSION: The findings from our preliminary study suggest that Mammaprint may achieve better separation of high risk from low risk patients. However, it is possible that having more genes in multigene assays would better capture the heterogeneity of hormone receptor positive breast cancer and guide choice of optimal systemic therapy to reduce risk of metastases. Citation Format: Ibraheem AF, Olopade O, Huo D. Comparative analyses of the prognostic value of oncotype and mammaprint using the National Cancer Database [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-12.

Increased Mortality Risk among Early Stage Hormone Receptor Positive Breast Cancer Patients Who Did Not Receive Adjuvant or Neoadjuvant Therapy

Background: Hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) is the most common biologic subtype of breast cancer. Although adjuvant therapy has demonstrated a survival benefit in clinical trials, its use is poorly understood in the real-world among elderly breast cancer patients since age is a barrier to receiving adjuvant therapy. An examination of treatment patterns and outcomes associated with receipt of adjuvant/neoadjuvant therapy among elderly HR + HER2-breast cancer patients was undertaken. Methods: There were 18,470 HR + HER2-breast cancer patients from the linked SEER-Medicare database. Patients were diagnosed with stage I-III disease between 1/1/2007-12/31/2011, ≥66 years, enrolled in Medicare Parts A, B and D, and underwent breast cancer surgery after diagnosis. Time-varying Cox proportional hazards regression assessed overall survival. Results: There were 13,670 (74%) patients treated with adjuvant/neoadjuvant therapy and 4800 (26%) untreated. Compared to treated patients, untreated patients were older, had earlier stage, lower grade, smaller tumors, poorer performance, higher comorbidity score, and less use of a 21-gene recurrence score (RS) assay (p n RS assay was associated with lower risks. The Cox model showed a 48% higher risk of death in untreated compared to treated patients. In a subset of 8967 patients with stage I disease, tumor size Conclusions: Older patients with favorable clinical characteristics (earlier stage, smaller tumor, lower grade) are less likely to be treated and have a higher risk of death compared to adjuvant/neoadjuvant treated patients. An unmet need among older breast cancer patients persists.

Abstract P3-12-12: Serum estrogen-levels in women 48-56yrs with hormone receptor-positive breast cancer. Cross-Sectional study using an ultra-sensitive LC-MS/MS-method

Abstract Background and Purpose: Randomized clinical trials in early stage hormone receptor positive breast cancer (HR+BC), have shown that total estrogen suppression (TES) for 5 yrs or after 2-3 yrs of tamoxifen treatment improved outcome over 5 yrs of TAM monotherapy. This relative improvement is in absolute figures most visible in patients with a high relapse risk. To achieve TES, women need to be (rendered) menopausal and treated with an oral aromatase inhibitor (AI). We measured serum estrogens in women of peri-menopausal age with HR+BC starting or on anti-hormonal agents. Methods: Serum estradiol (E2) and estrone (E1) were quantified using a sensitive liquid chromatography-tandem mass spectrometry method (LC-MS/MS; Pauwels et al. JCO 2013) in women 48-56 yrs old with HR+BC starting or on anti-hormonal therapy in a cross sectional observational monocentric study. We report the frequency that (and explore why) AI-users had estrogens above the lower limit of quantification (LLOQ). We measured estrogen levels in TAM users with &amp;gt; 3 months' amenorrhea by previous use of (neo)adjuvant chemotherapy. Finally, we studied the frequency of both estrogens or either alone were &amp;lt; LLOQ in non-users. Statistics are descriptive; biomarkers for estrogen levels were analyzed using linear mixed models. [amendment on study NCT01223833] Results: Estrogen levels were assessed in 566 samples from 401 women; 96 (126 samples) were on AI, 128 (182 samples) on TAM and 217 (258 samples) non-users. Some patients had more than one blood sample in different groups. 13,5% of AI users were above LLOQ for E2 and E1; 7,5% for E1 alone. Some were due to ovarian reactivation. An important proportion (18%) of 83 non-hysterectomized TAM users with amenorrhea had E2 levels &amp;gt;40ng/L; 9,1% and 28.2% respectively in patients who had and didn't have (neo)adjuvant chemotherapy. None of non-users were below LLOQ for E1, while 20.7% were below LLOQ for E2. Conclusions:TES is not always achieved in AI-users; reasons why were multiple. Amenorrhea is no guarantee for TES in TAM users, as a significant proportion had high E2 levels even when previously exposed to (neo)adjuvant chemotherapy. Using LC-MS/MS, undetectable levels for E1 better reflect TES than below LLOQ for E2. Citation Format: Van Houdt M, Neven P, Anneleen L, Ivo J, Dirk V, Jaak B, Annouschka L, Hans W. Serum estrogen-levels in women 48-56yrs with hormone receptor-positive breast cancer. Cross-Sectional study using an ultra-sensitive LC-MS/MS-method [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-12-12.

Abstract P1-06-05: Clinical practice and mortality in patients with oncotype DX intermediate score: What do we know about the gray zone?

Abstract BACKGROUND: The 21 gene expression signature Oncotype DX (ODX) is a powerful predictor of disease outcome in early stage hormone receptor positive breast cancer. ODX can be used for better risk stratification of patients who may benefit from chemotherapy. ODX testing increases confidence in treatment decisions especially when ODX recurrence score (RS) is low or high. However, for the intermediate RS, decisions on receiving chemotherapy or not is a joint decision made by the physician and patient, in part because results from the TAILORx and RxPONDER randomized clinical trials addressing this very important clinical question has yet to be published. OBJECTIVE: To examine “real world” oncology practice and survival outcome for breast cancer patients with ODX RS score in the intermediate range. METHODS: A retrospective cohort of women diagnosed with early stage, hormone receptor positive breast cancer whose ODX score was in the intermediate range was established using the National Cancer Data Base (NCDB), 2009-2013. We assessed the relationship of overall survival with chemotherapy receipt and RS score using Cox proportional hazards models adjusted for patient characteristics, including age, race/ethnicity, grade, year of diagnosis, Charlson Co-morbidity Index, lymphovascular invasion, nodal involvement, tumor size, and histology. Intermediate RS score was analyzed as both continuous variable and categorical variables (18-20, 21-23, 24-26, and 27-30). RESULTS: Of 24,945 females reported to have intermediate ODX score, 10,179 (41.4%) received chemotherapy. Receipt of chemotherapy depended on ODX score monotonically, ranging from 19.1% in patients with RS = 19 to 76.1% in patients with RS = 30. In total, 426 patients have died from all causes. Overall, chemotherapy receipt was associated with a statistically significant reduction in the risk of death (hazard ratio=0.77; 95% confidence interval [CI]: 0.62-0.96, p=0.02) in multivariable Cox model. RS score was statistically positively associated with increased risk of death, with one unit increment in RS corresponding to 6.2% increased mortality risk (95% CI 3.2%- 9.2%, p&amp;lt;0.0001). Using a categorical scale, we found patients with intermediate ODX scores in RS 27-30 range had 1.64-fold increased risk of death (95% CI: 1.13-2.37) compared to patients with ODX scores in RS 18-20 range.. The association between ODX score and overall survival was more pronounced in women younger than 50 (hazard ratio per 1 unit increment = 1.28, 95% CI: 1.17-1.40) than in women 50 years or older (hazard ratio per 1 unit increment = 1.04, 95% CI: 1.01-1.07). CONCLUSION: Our analysis revealed the ODX score in the intermediate range still has prognostic value for overall survival especially for young-onset breast cancer patients, which is independent of other clinopathologic factors. As we eagerly await results from randomized clinical trials, young women with intermediate RS should be counseled to consider more aggressive treatment including chemotherapy, ovarian function suppression or participation in ongoing clinical trials of CDK inhibitors to improve overall survival outcomes. Citation Format: Ibraheem AF, Press D, Dezheng H, Olopade F. Clinical practice and mortality in patients with oncotype DX intermediate score: What do we know about the gray zone? [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-06-05.

Abstract P2-09-19: Genomic biomarker for resistance to palbociclib in the NeoPalAna trial

Abstract Background: Cyclin-dependent kinase (CDK) 4/6 inhibitors are being evaluated in the adjuvant setting for patients with resected early stage hormone receptor positive (HR+) and HER2 negative (HER2-) breast cancer (BC). However, biomarkers that predict benefit from this class of agents are unknown. We have recently reported results from the phase II neoadjuvant NeoPalAna trial which demonstrated that palbociclib (Pal) enhanced the anti-proliferative activity when added upon anastrozole (Ana) monotherapy in estrogen receptor (ER) positive and HER2 negative breast cancers. Interestingly, a small group of patients was resistant to Pal, exhibiting persistent tumor cell proliferation (Ki67 &amp;gt;2.7%) on the combination of Ana and Pal. In this study, we evaluated the utility of a research algorithm for the 70-gene signature (70-GS) in identifying Pal resistant versus sensitive patients. Methods: Serial biopsies were collected from patients at four treatment timepoints: baseline (BL), cycle 1 day 1 (C1D1) following 28 days of Ana monotherapy, cycle 1 day 15 (C1D15) at 2 weeks post the addition of Pal, and at surgery (Surg). RNA was extracted from frozen tumor biopsies at each timepoint and run on Agilent full genome microarrays (GSE93204) at Washington University. As an exploratory analysis, genes from the GPL8253 array that match the 70-GS were used to calculate a research approximation of the 70-GS index (r-GS). The distribution of the r-GS across Ki67 response groups was evaluated. Results: Ki67 had previously been measured at each timepoint, and used to classify patients as being either Ana-sensitive (C1D1 Ki67 ≤2.7%), Pal-sensitive (C1D1 Ki67 &amp;gt;2.7%, C1D15 Ki67 ≤2.7%), or Pal-resistant (C1D15 Ki67 &amp;gt;2.7%). The r-GS was differentially regulated between sensitive (AI or Pal) and Pal-resistant groups at BL (p=0.012), C1D1 (p=0.039), and C1D15 (p=0.022). The r-GS values varied widely across patients at BL, and generally became more positive (more low risk) with treatment. There was no correlation between Ki67 levels and r-GS. Furthermore, gene expression analysis was performed to elucidate the difference between Pal-sensitive vs. Pal-resistant patients, and Ana-sensitive vs. Pal-sensitive patients. Conclusions: While on-treatment Ki67 indicated drug responsiveness, baseline r-GS significantly stratified patients into sensitive (Ana or Pal) versus Pal-resistant groups in the neoadjuvant setting. This preliminary finding suggests that the 70-GS may have clinical utility in identifying patients resistant to Pal for future studies. Additionally, results of the gene expression analysis may help to further develop genomic biomarkers for Pal and Ana sensitivity and resistance. Citation Format: Hoog JW, Treece T, Blumencranz L, Audeh W, Sanati S, Ellis MJ, Ma CX. Genomic biomarker for resistance to palbociclib in the NeoPalAna trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-19.

Adoption Patterns and Predictors of De-escalated Adjuvant Therapy for Older Women With Early Stage Hormone Receptor Positive Breast Cancer

Breast conserving surgery (BCS) without adjuvant radiation therapy (RT), followed by endocrine therapy (ET) is a proven alternative for older women with stage I hormone receptor-positive (HR+) breast cancer. However, the extent of adoption of the ET-only approach following publication of phase III clinical trial (initially published in 2004 with a median follow-up of 5 years and again in 2013 with a median follow-up of 12.6 years) data in the past decade is unknown. We examined patterns of adjuvant ET and RT treatment among women age 70+ and predictors of radiation use in a large national cohort during the adoption period. We used pooled data from the Surveillance Epidemiology and End Results (SEER)-Medicare with a National Program of Cancer Registries (NPCR)-Medicare linked database to evaluate a cohort of 7,368 women age 70+ with stage I or II, node negative and HR+ breast cancers. Women were diagnosed between 2007 and 2011, received BCS, and no chemotherapy within 12 months of diagnosis. Patients were grouped into those receiving ET only, RT only, or ET+ RT, and the proportion of patients assigned to each treatment was examined by year. Multivariable logistic regression was used to evaluate predictors of treatment assignment. Results: Among stage I patients, 50.6% received RT+ET, while 13.4% received ET only and 20.7% received RT only. 15.3% of stage I patients received no adjuvant therapy after BCS. Among stage II patients, 53.4% received RT+ET, while 15.2% received ET only, 12.9% RT only, and 18.2% received no adjuvant therapy. The proportion of stage I patients receiving RT as part of adjuvant therapy decreased slightly over time but remained high (73.2% in 2007 versus 69.8% on 2011); for stage II patients receipt of adjuvant radiation remained stable over time at approximately 66%. In adjusted analysis of patients who received either ET alone or RT+ET, stage was not an independent predictor of receiving combined therapy. Predictors of receiving ET alone included older age, co-morbid conditions, and grade 1 tumors. Predictors of treatment assignment were generally similar for stage I and II patients, but black women were more likely than non-Hispanic whites to receive ET alone for stage II disease (OR=1.92; 95% CI=1.16,3.16). RT+ET remains the most common adjuvant treatment choice for older women with stage I HR+ breast cancer. Uptake of ET-only adjuvant therapy appears to be low, despite randomized phase III data supporting ET alone as a treatment option. A substantial minority of patients receive neither adjuvant therapy, possibly due to non-initiation of prescribed ET. More work is needed to evaluate the system-level determinants of radiation use in this population, and to understand the reasons for low adoption of radiation-sparing treatment strategies.

Which patient characteristics drive treatment decisions in elderly patients with early stage hormone receptor–positive breast cancer?

538 Background: Hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) is the most common biologic subtype of breast cancer (BC). We examined treatment patterns and outcomes associated with adjuvant or neoadjuvant therapy among elderly patients (pts) in the US. Methods: The analysis included 18,470 first primary HR+HER2- BC pts from the linked SEER-Medicare database. Pts were diagnosed with Stage I-III disease between 1/1/2007-12/31/2011, ≥66 years, continuously enrolled in Medicare Parts A/B in the year prior to diagnosis, enrolled in Part D in the year after diagnosis, and underwent BC surgery ≤6 months after diagnosis. Time-varying Cox proportional hazards regression assessed overall survival adjusting for pt characteristics. Date of last follow-up was 12/31/2013. Results: There were 13,670 (74%) pts treated with hormonal therapy +/- chemotherapy and 4,800 (26%) untreated. Compared to treated pts, untreated pts were older, had earlier stage, lower grade, smaller tumors, poorer performance, higher comorbidity, and less genomic testing for risk of recurrence (p&lt;0.0001). In a multivariate analysis, increasing age, stage, tumor size, tumor grade, comorbidity score and poor performance were significantly associated with higher mortality risks, while use of genomic testing was associated with a lower risk of death. The Cox model showed a 48% higher risk of death in untreated compared to treated pts (HR=1.48; 95% CI=1.35-1.61). Even in a subset of 8,967 pts with stage I disease, tumor size &lt;2.0cm and grade 1/2; untreated pts had a 22% higher risk of death compared to treated pts (HR=1.22; 95% CI=1.05-1.41). Conclusions: Patients who are older with favorable disease characteristics (earlier stage, smaller tumor, lower grade) are less likely to be treated and have a higher risk of death compared to pts who received adjuvant or neoadjuvant therapy. The unmet need among elderly BC pts remains, suggesting that age should not deter guideline-based therapy. [Table: see text]

Health economic impact of breast cancer index (BCI) in patients with hormone responsive breast cancer (HRBC) considering extended adjuvant endocrine therapy (EET).

25 Background: Previous research has demonstrated the benefit of EET for HRBC, however, the absolute benefit is modest and commits women to an extra 5 yrs of treatment. The Breast Cancer Index (BCI) is a gene expression-based test that has been validated to quantify the risk of late recurrence (BCI subscore) and to predict likelihood of benefit from EET (H/I subscore). We have previously shown that the use of BCI increases patient and physician confidence in decision-making and leads to fewer recommendations for EET. The current analysis extends our results to a larger sample size and presents a health economic analysis to assess the cost effectiveness of the use of BCI for EET decision-making. Methods: We developed a fact-based economic model to project the cost effectiveness of BCI using a cohort of 140 patients with stage I-III HRBC from Yale Cancer Center and University of Pittsburgh Medical Center who had completed ≥3.5 yrs of endocrine therapy and had undergone BCI testing in the context of this study. Physicians completed questionnaires to indicate their recommendations for EET before and after BCI results. Costs associated with EET, toxicity, follow-up, and metastatic recurrence were modeled over 5 yrs of extended therapy. Model inputs were based on published literature. Sensitivity analyses were performed around key inputs to estimate effects on the model. Results: Changes in EET recommendations after BCI were observed in 29% of patients, with 21% changing from recommended to not recommended, and 8% from not recommended to recommended. The projected net cost savings of BCI testing in this population of patients who are disease free at 5 yrs post-diagnosis is $5,190 per patient tested. Gross cost savings were projected to be achieved through reduced recurrence in patients receiving EET based on BCI results and decreased adverse events and comorbidities for patients with low BCI scores who did not receive EET. Conclusions: Based on the decision impact of BCI in a real-world cohort, the test is projected to be cost saving for women with early stage hormone receptor positive breast cancer who are recurrence free at 5 yrs post-diagnosis on adjuvant endocrine therapy.

Abstract P2-05-33: Refining the prognostic value of Ki67 biomarker by ataxia telangiectasia mutated (ATM) status in a retrospective study of early stage hormone receptor positive breast cancer

Abstract Purpose: The current study was designed to investigate the combined influence of ataxia telangiectasia mutated (ATM) and Ki67 on clinical outcome in early stage hormone receptor positive breast cancer (ES-HPBC), particularly in patients with smaller tumors (&amp;lt; 4 cm) and fewer than four positive lymph nodes. Methods: Formalin-fixed paraffin-embedded specimens of resected primary breast tumors from 532 patients diagnosed with early stage breast cancer were used to construct a tissue microarray. Samples from 297 patients were suitable for final statistical analysis. We detected ATM and Ki67 proteins using immunohistochemistry and quantified their expression with digital image analysis. Data on expression levels were subsequently correlated with clinical outcome. Results: Remarkably, ATM expression was useful to stratify the low Ki67 group into subgroups with better or poorer prognosis. Specifically, in the low Ki67 subgroup defined as having smaller tumors and no positive nodes, patients with high ATM expression showed better outcome than those with low ATM, with estimated survival rates of 96% and 89% respectively at 15 years follow up (p = 0.04). Similarly, low-Ki67 patients with smaller tumors, 1-3 positive nodes and high ATM also had significantly better outcomes than their low ATM counterparts, with estimated survival rates of 88% and 46% respectively (p=0.03) at 15 years follow up. Multivariable analysis indicated that the combination of high ATM and low Ki67 is prognostic of improved survival, independent of tumor size, grade, and lymph node status (p = 0.02). Low Ki67/high ATM expression independently predicts favorable disease survival in a multivariate model in low Ki67 subgroup of ES-HPBC (Stage I-III)Variablesp valueHR (95%CI)Low Ki67/high ATM vs Low Ki67/low ATM0.020.36 (0.15-0.88)ize (T1/2 vs T3/4)0.010.16 (0.04-0.69)LN status (- vs +)0.140.49 (0.20-1.25)LVI (_- vs +)0.160.51 (0.20-1.31)Grade (1/2 vs 3)&amp;lt;0.00010.28 (0.11-0.67)Age (&amp;lt;65 vs &amp;gt;65)0.010.26 (0.10-0.74) Conclusions: These data suggest that the prognostic value of Ki67 can be improved by analyzing ATM expression in ES-HPBC. Citation Format: Feng X, Li H, Kornarga E, Dean M, Lees-Miller S, Riabowol K, Magliocco A, Morris D, Watson P, Enwere E, Bebb G, Paterson A. Refining the prognostic value of Ki67 biomarker by ataxia telangiectasia mutated (ATM) status in a retrospective study of early stage hormone receptor positive breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-05-33.

Comparison of health utility weights among elderly patients receiving breast-conserving surgery plus hormonal therapy with or without radiotherapy

Background: The selection of the most appropriate treatment combinations requires the balancing of benefits and harms of these treatment options as well as the patients’ preferences for the resulting outcomes.Objective: This research aimed at estimating and comparing the utility weights between elderly women with early stage hormone receptor positive (HR+) breast cancer receiving a combination of radiotherapy and hormonal therapy after breast conserving surgery (BCS) and those receiving a combination of BCS and hormonal therapy.Methods: The Surveillance, Epidemiology, and End Results (SEER) linked with Medicare Health Outcomes Survey (MHOS) was used as the data source. Health utility weights were derived from the VR-12 health-related quality of life instrument using a mapping algorithm. Descriptive statistics of the sample were provided. Two sample t-tests were performed to determine potential differences in mean health utility weights between the two groups after propensity score matching.Results: The average age at diagnosis was 72 vs. 76 years for the treated and the untreated groups, respectively. The results showed an inverse relationship between the receipt of radiotherapy and age. Patients who received radiotherapy had, on average, a higher health utility weight (0.70; SD = 0.123) compared with those who did not receive radiotherapy (0.676; SD = 0.130). Only treated patients who had more than two comorbid conditions had significantly higher health utility weights compared with patients who were not treated.Conclusions: The mean health utility weights estimated for the radiotherapy and no radiotherapy groups can be used to inform a comparative cost-effectiveness analysis of the treatment options. However, the results of this study may not be generalizable to those who are outside a managed care plan because MHOS data is collected on managed care beneficiaries.