ATAC Trial Research Articles

Abstract PL1: Genomic Profiling in Early Stage ER Positive Breast Cancers/Precision Medicine

Abstract Genomic profiling has become mainstream for the management of early ER+ breast cancer and has become a favoured approach for research into pathways that govern prognosis and response and resistance to medical therapies.Management: Several commercial tests are available for the assessment of residual risk of recurrence of patients receiving hormonal therapies. We have compared several of these in postmenopausal patients treated with anastrozole or tamoxifen in the ATAC trial, including OncotypeDX (ODX), Prosigna (PAM50) and EndoPredict (EP). While PAM50 and EP provide estimates of risk that by design integrate tumour size and nodal status, estimates from ODX are also improved substantially by integration with clinicopathologic factors. The 3 tests include genes related to proliferation and to dependence on estrogen signalling with the ODX being dominated by the latter and PAM50 by the former. This may explain the better performance of the PAM50 than ODX at cessation of endocrine treatment after 5 years when the outcome for patients with high ER appears to worsen. While the tests have largely been validated in postmenopausal cases they are used in premenopausal cases as well. We found that while individual gene modules varied in expression across the menstrual cycle there was little systemic variability in the overall estimates of risk. Our recent work has indicated that mutations in TP53 add significant prognostic information to that from the commercial profiling tests.Research: We have conducted genomic analyses during presurgical therapy of ER+ breast cancer to determine the key pathways of endocrine resistance using change in Ki67 as the end-point of response. Very few tumours with low levels of ER by IHC (<10% positive cells) or rtPCR showed a Ki67 response. A group of the most widely studied genes in breast cancer including FOS and JUN show very marked increases in expression during surgical procedures and can lead to erroneous interpretation in the absence of controls. Considering intrinsic subtypes, tumours categorised as basal-like or HER2-enriched have little chance of Ki67 response; luminal B tumours showed a slightly lower chance of response. GSEA revealed that several hallmarks reflecting immune signalling were those most strongly associated poor Ki67 response with the interferon gamma and alpha and IL6-JAK-STAT3 signalling hallmarks being particularly involved. TME deconvolution indicated a broad involvement of many immune cell types. Other hallmarks of resistance included E2F target genes and hypoxia. Mutation of TP53 was strongly associated with Ki67 poor response. RNAseq profiling of patients treated with palbociclb as well as letrozole revealed high CCNE1 expression as associated with endocrine resistance. Citation Format: M Dowsett. Genomic Profiling in Early Stage ER Positive Breast Cancers/Precision Medicine [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 PL1.

Abstract P1-17-06: Impact of body mass index on the efficacy of aromatase inhibitors in patients with metastatic breast cancer

Abstract Background: Aromatase inhibitors (AIs) are part of standard endocrine therapy for hormone receptor (HR)-positive breast cancer (BC) and are used in both adjuvant and metastatic settings. Since AIs work by inhibiting the conversion of androgens to estrogen in peripheral adipose tissue, the higher levels of estrogen in obese patients may lead to incomplete inhibition by AIs and influence their efficacy. A retrospective analysis of the ABCSG-12 trial found that overweight premenopausal patients with early-stage BC treated with anastrozole had a 60% increased risk of disease recurrence and more than doubling in risk of death compared with normal weight patients on anastrozole. Similarly, an exploratory analysis from the ATAC trial found that in post-menopausal women with early-stage BC, overall recurrence rates were lower in patients randomized to anastrozole versus tamoxifen but in women with body mass index (BMI) > 30, there was no significant difference in disease recurrence between anastrozole and tamoxifen. While these findings raise concern for the efficacy of adjuvant AI therapy in obese patients with early-stage BC, this has not yet been demonstrated in the metastatic setting. The aim of this study was to determine the impact of BMI on efficacy of AIs in patients with metastatic HR-positive BC. Methods: We performed a retrospective chart review of all female patients with metastatic HR-positive BC on an AI in first- or second-line settings and seen at our academic institution between 2001-2020. The primary endpoint was progression-free survival (PFS), defined as the time from start of AI to disease progression or death from any cause. PFS was compared across BMI groups using Kaplan-Meier curves and log-rank tests. Cox proportional hazards regression model was used for univariate and multivariate analyses. Results: We identified 219 patients who had received an AI in the first- or second-line settings for metastatic HR-positive BC and with documented information on BMI. The median age was 59 with 45% of patients White, 29% African American, 16% Hispanic/Latino, 5.5% Asian and remainder other/unknown. 32% (71) had HER-2 positive disease. 82% (179) were on an AI in the first-line setting. Overall, 53% were on letrozole, 42% on anastrozole and 5.5% on exemestane. Of the 219 patients, 56% (123) had a low BMI (defined as < 27 kg/m2) and 44% (96) had a high BMI (≥ 27 kg/m2; based on the Breast Cancer Weight Loss [BWEL] trial). The median PFS was 21.9 months (95% CI, 14.5 to 28.4) in the low BMI group versus 20.2 months (95% CI, 14.3 to 27.5) in the high BMI group with no statistically significant difference (p =0.73). There were 8 (6.5%) deaths in the low BMI group and 7 (7.3%) deaths in the high BMI group. Multivariate cox regression model did not demonstrate any significant impact of BMI on PFS when adjusting for age, race/ethnicity, HER2 status, type of AI, line of therapy, drug partner and type of metastatic disease (HR =0.91, 95% CI =0.64 to 1.30, p =0.6 for high BMI group). Subgroup analysis of patients on an AI in the first line setting also did not show a significant difference in PFS with median PFS 19.3 and 18 months in the low and high BMI groups, respectively. Conclusions: In patients on an AI for metastatic HR-positive breast cancer, there was no statistically significant difference in PFS in patients with low versus high BMI. While BMI influences efficacy of AIs in the adjuvant setting, our results demonstrate that in the metastatic setting, BMI does not significantly impact the efficacy of AIs among our patient population. This discrepancy could be due to other differences in disease characteristics that make complete aromatase inhibition more important in the adjuvant setting when disease burden is the lowest. Additional larger studies are needed to confirm this finding. Citation Format: Rima Patel, Zhiqiang Li, Brittney S. Zimmerman, Marc Y. Fink, Jason D. Wells, Xiang Zhou, Kristin L. Ayers, Arielle Redfern, Scott Newman, Rong Chen, William K. Oh, Amy Tiersten. Impact of body mass index on the efficacy of aromatase inhibitors in patients with metastatic breast cancer [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 P1-17-06.

Molecular Drivers of Oncotype DX, Prosigna, EndoPredict, and the Breast Cancer Index: A TransATAC Study.

PURPOSEThe Oncotype DX Recurrence Score (RS), Prosigna Prediction Analysis of Microarray 50 (PAM50) Risk of Recurrence (ROR), EndoPredict (EP), and Breast Cancer Index (BCI) are used clinically for estimating risk of distant recurrence for patients receiving endocrine therapy. Discordances in estimates occur between them. We aimed to identify the molecular features that drive the tests and lead to these differences.PATIENTS AND METHODSAnalyses for RS, ROR, EP, and BCI were conducted by the manufacturers in the TransATAC sample collection that consisted of the tamoxifen or anastrozole arms of the ATAC trial. Estrogen receptor–positive/human epidermal growth factor receptor 2 (HER2)–negative cases without chemotherapy treatment were included in which all four tests were available (n = 785). Clinicopathologic features included in some tests were excluded from the comparisons. Estrogen, proliferation, invasion, and HER2 module scores from RS were used to characterize the respective molecular features. Spearman correlation and analysis of variance tests were applied.RESULTSThere were moderate to strong correlations among the four molecular scores (ρ = 0.63-0.74) except for RS versus ROR (ρ = 0.32) and RS versus BCI (ρ = 0.35). RS had strong negative correlation with its estrogen module (ρ = −0.79) and moderate positive correlation with its proliferation module (ρ = 0.36). RS’s proliferation module explained 72.5% of ROR’s variance, while the estrogen module explained only 0.6%. Most of EP’s and BCI’s variation was accounted for by the proliferation module (50.0% and 54.3%, respectively) and much less by the estrogen module (20.2% and 2.7%, respectively).CONCLUSIONIn contrast to common understanding, RSs are determined more strongly by estrogen-related features and only weakly by proliferation markers. However, the EP, BCI, and particularly ROR scores are determined largely by proliferative features. These relationships help to explain the differences in the prognostic performance of the tests.

Oral Analgesic Use in Postmenopausal Women After Curative Breast Cancer Treatment: Post Hoc Analysis of the ATAC Trial

Aim: To evaluate analgesic use and associated conditions in postmenopausal women who had undergone curative breast cancer treatment. Materials & methods: This post hoc analysis used the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial database, which included patient reports of concomitant medications and associated indications during follow-up. Results: Of 3434 women with eligible concomitant medication data, 71.8% reported oral analgesic use. Of 2321 patients using analgesics ≥30 days, 47.9% reported opioid use. Musculoskeletal pain was the most common indication for oral analgesic use. Of patients using opioids, 28.1% reported concomitant laxative use. Conclusion: Approximately half of the patients reported opioid use, most commonly for noncancer (musculoskeletal) pain, suggesting that breast cancer survivors experience chronic pain that should be appropriately managed.

Using time series analysis to forecast the health-related quality of life of post-menopausal women with non-metastatic ER+ breast cancer: A tutorial and case study.

Time series models are widely used forecasting techniques in health care for long time series and are typically built in commercial statistical packages. However, for short time series data, such as health-related quality of life (HRQoL), guidance on how to select and use appropriate time series models is lacking. This tutorial provides a step-by-step guide adopting a time series analysis framework for HRQoL forecasting. We walk through a case study examining the forecasting of the effects of adjuvant endocrine therapy on the HRQoL of post-menopausal women with non-metastatic ER+breast cancer using data from the HRQoL sub-protocol of the Tamoxifen arm of the Arimidex, tamoxifen, alone or in combination (ATAC) trial. The forecasting of HRQoL consists of four steps: 1) data extraction and accuracy check, 2) forecasting horizon definition and identification of data pattern, 3) forecasting model identification and fitting using five forecasting approaches appropriate for short time series ((i) double exponential smoothing, (ii) double moving average, (iii) fuzzy forecasting, (iv) grey forecasting, and (v) Volterra series), 4) forecasting model selection. A user-friendly visual basic for applications (VBA) Excel add-in is made available to interested users to facilitate the application of the tutorial. The Grey method and Volterra series appeared to be good candidates to forecast the effects of adjuvant endocrine therapy on the HRQoL of post-menopausal women with non-metastatic ER+breast cancer enrolled in the ATAC trial. It is feasible to forecast the effects of treatments on HRQOL even when the time series is short.

Abstract P4-08-02: Importance of adverse events during endocrine treatment for the prediction of late distant recurrences

Abstract Background: During endocrine treatment of breast cancer, the occurrence of symptoms related to oestrogen depletion are important predictor of treatment efficacy. We have previously shown that appearance of vasomotor and joint related symptoms are a useful biomarker for a greater response to endocrine treatment (Cuzick et al., Lancet, 2008). Furthermore a prediction model including clinicopathological parameters (CTS5) has shown to be a good prognostic tool for the prediction of late distant recurrences (DR) (Dowsett et al., JCO, 2018). Here, we assessed whether the occurrence of endocrine related adverse events were predictive of late DR in the ATAC trial. Methods: The ATAC trial (N=4735) of postmenopausal women with estrogen receptor positive breast cancer treated with 5 years' tamoxifen or anastrozole was used for this analysis. Women who reported symptoms (hot flashes, joint symptoms, gynaecological symptoms) at any time during the trial were compared to those not reporting these symptoms for late DR. Time to late DR, defined beginning at 5 years after randomization, was the primary endpoint. Hazard ratios (HR) and corresponding 95% CIs were estimated by Cox proportional hazards regression models. Results: 2937 women (62%) who were recurrence free after 5 years, reported either hot flashes, joint symptoms, or gynaecological symptoms during the active treatment period. Women who reported joint symptoms (adjusted for CTS5: HR=0.74 (0.59-0.94)), or gynaecological symptoms (adjusted for CTS5: HR=0.68 (0.47-0.97)) had significantly fewer late DR compared to those not reporting these events during the active 5 years' treatment period. Those who reported any symptom during the treatment period had an overall 34% lower risk of a late DR (univariate: HR=0.66 (0.53-0.83), P<0.001; adjusted for CTS5: HR=0.75 (0.60-0.93), P=0.009). The 5-10 year DR risk for women who reported any symptoms was 7.4% (6.4-8.5) compared to 11.0% (9.3-12.8) for those without symptoms. Women who reported any symptoms and who were randomized to either anastrozole (HR=0.67 (0.48-0.92)) or tamoxifen (HR=0.65 (0.48-0.88)) had significantly fewer late DR compared to those not reporting these symptoms. Women with symptoms on tamoxifen did have better 10-year DR risk compared to those without symptoms on anastrozole (8.1% (6.7-9.8) vs. 9.8% (7.7-12.4)). Conclusions: This retrospective analysis of the ATAC trial showed that occurrences of endocrine related symptoms during the treatment period are associated with the risk of developing a late DR, irrespective of treatment allocation. Larger effects were found for joint or gynaecological symptoms and remained significant after adjustment for clinical parameters. These findings might help clinicians and patients in their decision making process about extended endocrine therapy. Citation Format: Sestak I, Dowsett M, Cuzick J. Importance of adverse events during endocrine treatment for the prediction of late distant recurrences [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 P4-08-02.

Abstract ES5-2: Clinical and molecular profiles to identify who is at risk?

Abstract The persistent risk of recurrence from ER-positive primary breast cancer has been known for many years. It was recently described in detail and in relation to baseline clinicopathologic factors in a meta-analysis by the EBCTCG. This involved nearly 63,000 patients that had been prescribed 5 years of endocrine therapy and had reached the end of that time recurrence-free (Pan et al, NEJM, 2017, 377, 1836). Among other things this revealed that even among patients with T1N0 disease 13% had a distant recurrence between years 5 and 20. Our group have previously created a Clinical Treatment Score (CTS) from nodal status, tumor size, grade, age and type of adjuvant endocrine treatment and validated this for estimating risk of distant recurrence from the time of diagnosis. Drawing on a training dataset of 4,735 patients from the ATAC trial and a validation set of 6,711 patients from the BIG1-98 trial we created the CTS5, a prognostic score of risk from year 5, that features the same factors as CTS other than type of endocrine treatment (Dowsett et al, JCO, 2018, 36, 1941). Of note, only 4/304 patients with one to three positive nodes that were categorized as low risk in the validation set had a distant recurrence between years 5 and 10. The CTS5 calculator can be accessed online at www.cts5-calculator.com. There are several commercially available molecular profiles that estimate the risk of recurrence over years 0-10 after diagnosis in endocrine-treated primary breast cancer. In the TransATAC study some of these, including the EPClin and PAM50-ROR, show similar prognostic information over years 5-10 (after 5 years of endocrine therapy) as they do over years 0-5 (during endocrine therapy). In contrast, while the Oncotype Recurrence Score (RS) showed similar prognostic information to EPClin and PAM50-ROR in years 0-5 its performance in years 5-10 was substantially worse. Examination of the time-dependent prognostic relationship of each of the individual genes and modules in the RS showed that those patients with higher ER signaling had good prognosis before year 5 but poorer after year 5, suggesting that the cessation of endocrine therapy may lead to this poorer post-5 year outcome (Dowsett et al Clin Cancer Res, 2015, 21, 2763). A broad-based assessment of gene expression in the TransATAC sample set found that there was limited potential to identify a prognostic profile that performed substantially better after 5 years (Buus et al, Breast Cancer Res, 2018, 20, 103). One test, the 7-gene Breast Cancer Index, has reported on a relatively small sample set that it can predict the benefit or not from extended adjuvant endocrine therapy. Further validation studies of this are warranted as well as other tests that provide the same predictive information. Citation Format: Dowsett M. Clinical and molecular profiles to identify who is at risk? [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 ES5-2.

Abstract P4-09-01: A multi-study correlative analysis of change in Ki67 in the neoadjuvant setting and disease free survival improvement in the adjuvant setting

Abstract Background: Based on results from the ATAC and IMPACT trials, Dowsett et al.1 hypothesized that “short-term changes in proliferation in the neoadjuvant setting may be able to predict outcome during adjuvant use of the same treatments.” Recent neoadjuvant studies2,3,4 of novel agents for HR+ breast cancer used Ki67, a biomarker for cell proliferation, as an endpoint for evaluating biological activity. However, the potential of this endpoint for predicting the adjuvant efficacy of therapeutic agents remains highly uncertain, motivating continued study based on clinical data. After curating relevant data from multiple trials (in both the neoadjuvant and adjuvant settings), a statistical model was constructed to evaluate the current evidence regarding this hypothesis. Methods: Data were collated from randomized trials of systemic therapies in post-menopausal women with HR+ breast cancer reporting Ki67 reduction in the neoadjuvant setting (7 studies) or disease-free survival (DFS) in the adjuvant setting (5 studies). A Bayesian hierarchical joint network meta-analysis model was constructed and fit to the data to evaluate: (1) if there is an association between study-level neoadjuvant Ki67 reduction for a given regimen and corresponding adjuvant DFS hazard ratio, and (2) if the relationship does exist, what DFS effect does it predict for various regimens for which only neoadjuvant data are currently available. Results: The results of the statistical model indicate that effect-size based on neoadjuvant Ki67 correlates with adjuvant (DFS) hazard ratio. Using neoadjuvant Ki67 data for several therapies for which adjuvant data are presently unavailable, we demonstrated how forecasts (and associated confidence intervals) of adjuvant effect-size may be produced using the model. Conclusions: While randomized trials yielding paired data from both clinical settings are sparse, this assessment using a statistically rigorous approach sheds additional light on the hypothesis of a correlation between neoadjuvant Ki67 changes and adjuvant DFS improvements. This analysis suggests the potential utility of Ki67 as a surrogate endpoint to screen/prioritize experimental regimens for development in the adjuvant setting.

Abstract OT3-02-04: A randomized controlled trial comparing acupuncture versus usual care for the treatment of aromatase inhibitor-induced arthralgia (AIIA) in women with early-stage breast cancer

Abstract BACKGROUND: The increase in breast cancer (BC) survival is largely due to the benefits of hormonal therapy, such as tamoxifen and aromatase inhibitors (AIs), for the treatment of hormone-sensitive breast cancer. Recent clinical trials have demonstrated that AIs are more effective than tamoxifen at reducing BC recurrences. However, BC patients receiving AIs have a higher incidence of osteoporosis, bone fractures, and musculoskeletal symptoms, particularly joint pain and stiffness. The incidence of AIIA in the ATAC trial was 27.8% in patients taking anastrozole versus (vs) 21% in patients taking tamoxifen (Baum M, Lancet 2002). The arthralgia associated with AIs can be so debilitating that it contributes to a significant percentage of non-compliance and discontinuation of systemic treatment. Patients with cancer often show interest in complementary and integrative modalities for symptom management (Vickers AJ, Lancet 2001), of which Acupuncture (Ac) is one of the most utilized therapies. ELIGIBILITY: Subjects must be female ≥18 years, have undergone mastectomy or breast-sparing surgery, and must have recovered from all pain-related effects of the surgery and radiotherapy with a minimum washout period of 30 days prior to registration. Patients should have ER and PR positive BC and be actively taking a 3rd-generation AI (Anastrozole, Letrozole, or Exemestane) for at least the 30 days prior to registration and plan to continue for at least one year after registration. ECOG PS <2 and platelets counts > 50,000/uL. Patients must not have received topical analgesic with exception of oral NSAIDS drugs ≤14 days to registration. TRIAL DESIGN: This is a 12-week, two arm randomized (1:1) trial evaluating the benefit of Ac in BC patients experiencing AIIA. AIMS: The aim of this study is to investigate the effectiveness of an integrative approach using Ac vs usual care (UC) treatment consisting of NSAIDs for the management of the AIIA.Primary endpoint is to compare the difference of Brief Pain Inventory-Short Form (BPI-SF) score at baseline vs week 8 between Ac and UC groups. Secondary endpoints are a) to compare the difference of BPI-SF score at baseline vs week 12 between Ac and UC groups, b) to compare the difference in AI adherence between Ac and UC groups and c) to compare the difference in patient initiated AI discontinuation between Ac and UC groups. STATS/TARGET ACCRUAL: This is a randomized controlled phase II study with the goal to compare reduction in BPI-SF score for patients treated with Ac vs UC alone. Patients are randomized 1:1 between the two arms. Prior work has indicated a 2-point BPI-SF score reduction as clinically meaningful. A sample size of 56 patients yields a study with 90% power and a one-sided significance level of 0.025 to determine a difference in pain reduction ≥2. These calculations are based on the assumptions of normal distribution of the improvement in BPI-SF score and a standard deviation that is conservatively calculated to be 2.3. An additional 6 patients will be accrued to account for attrition. Citation Format: Frank HS, Bendinger GM, Ensor Jr. JE, Neufeld N, Nixon D, Randolph K, McGuire E, Rados K, McNight JE, Pabbathi H, Panicker R, Johnson AT, Lammersfeld C, Alvarez R. A randomized controlled trial comparing acupuncture versus usual care for the treatment of aromatase inhibitor-induced arthralgia (AIIA) in women with early-stage 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 OT3-02-04.

Abstract P5-08-03: Prognostic impact of the combined risk groups by breast cancer index and HOXB13/IL17BR ratio in hormonal receptor positive, node negative breast cancer: A TransATAC study

Abstract Background: Breast Cancer Index (BCI) is a gene expression-based assay that reports two distinct results: 1) BCI predictive based on HoxB13/IL17BR ratio (H/I), and 2) BCI prognostic based on an algorithm incorporating H/I with the Molecular Grade index (MGI). Both biomarkers have been validated independently in randomized trial cohorts. However, integrated results to better correlate recurrence risk with endocrine response have not been evaluated. The aim of this post-hoc analysis was to examine patient outcomes within BCI prognostic and predictive groups using the translational arm of the Arimidex, Tamoxifen, Alone or in Combination trial (TransATAC). Methods: Primary tumor samples (N=742) from hormonal receptor-positive, N0 breast cancer patients treated with 5 years of tamoxifen (TAM) or anastrozole (ANA) in the ATAC trial were examined. Kaplan-Meier analysis was used to examine the risk of distant recurrence (DR) in patient subgroups derived from BCI and H/I results. A separate series of clinical cases submitted for BCI testing (N=853) were analyzed to determine distribution of the combined BCI and H/I groups in clinical practice. Results: Summary of patient distribution across the 6 BCI clinical subgroups showed that a large number of patients (331/742, 45%) were BCI low risk with low likelihood of benefit, whereas 108/742 (15%) of patients with endocrine responsive disease (High H/I) were classified as BCI low risk (Table 1). Kaplan-Meier analysis demonstrated that patients classified as BCI low risk had a very similar 10-year risk of DR irrespective of H/I status (H/I low: 5.5% vs. H/I high: 4.0%), indicating that prognosis was largely determined by BCI vs H/I. Table 1: Distribution of BCI and H/I risk groups in TransATAC BCI: PrognosticH/I: PredictiveLow RiskIntermediate RiskHigh RiskTotalLow Likelihood3318717435 (59%)High Likelihood10895104307 (41%)Total439 (59%)182 (25%)121 (16%)742 In 853 node negative cases submitted for BCI clinical testing, the distribution of BCI and H/I risk groups were similar to that from the TransATAC cohort (Table 2). Table 2: Distribution of BCI and H/I risk groups in clinical cases submitted for BCI testing BCI: PrognosticH/I: PredictiveLow RiskIntermediate RiskHigh RiskTotalLow Likelihood36410523492 (58%)High Likelihood96107158361 (42%)Total460 (54%)212 (25%)181 (21%)853 Discussion: Both prognostic and predictive components reported from the BCI assay may be used to stratify patients into 6 clinical subgroups based on prognostic risk of distant recurrence and endocrine responsiveness. Findings from this analysis indicate that patients classified as BCI low risk, regardless of H/I status, had sufficiently low DR rates and identifies patients that may be adequately treated with 5 years of endocrine therapy. Citation Format: Zhang Y, Sestak I, Schroeder BE, Dowsett M, Cuzick J, Schnabel CA, Sgroi DC. Prognostic impact of the combined risk groups by breast cancer index and HOXB13/IL17BR ratio in hormonal receptor positive, node negative breast cancer: A TransATAC study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-08-03.

Abstract P1-01-04: Early stage breast cancer prognostication using whole tumor or Ki67 heterogeneity-based digital imaging

Abstract Introduction: Accurate prognosis of hormone-positive early stage breast cancer patients offers the opportunity to make more informed follow-up choices, for example the addition of adjuvant chemotherapy. More recently patient prognostication based on immunohistochemistry-scored protein expression (ER, PR, Her2 and Ki67) in the ATAC trial has been described as IHC4 (C-index of 0.78). However, IHC4 clinical translation has not occurred and may be hindered by the need for a clinically-validated standardized assay as well as pathologist scoring reproducibility. To address this idea, we employed a standardized assay system and automated scoring using digital image analysis to assess either whole tumor (WT) IHC expression values or Ki67 heterogeneity (Ki67H) quantification. The goals were to 1) establish a prognostic model based on and potentially improving the IHC4 concept and 2) improve pathologist scoring reproducibility. Material and Methods: A paraffin-embedded whole tissue cohort consisting of 120 cases of hormone-positive, HER2-negative, stage I and II, breast cancer patient samples were re-stained with standardized ER, PR, HER2, and Ki67 IHC assays. Three pathologists independently scored conventional glass slides microscopically (CM) and annotated WT on H&E and Ki67 heterogeneous regions on whole slide scanned images (WSI) for each case separately. The annotations were separately registered across serial stained slides and also scored via the digital pathology algorithm. Results: The mean patient age at the time of diagnosis is 63 years with a maximum follow-up of 18 years. Patients with regional and/or distal recurrence compose 26% of the cohort with a median recurrence free survival of 8.5 years. years. Clinical variables (CV) plus WT (C-index 0.74, r2 0.38) or Ki67H (C-index 0.77, r2 0.39) models improved on patient prognostication each as compared to the IHC4 plus CV (C-index 0.70, r2 0.19) in this cohort. High inter-pathologist reproducibility for the IHC score, as measured by concordance correlation coefficient was noted for Ki67H (0.90). Conclusions: Novel algorithmic scoring methodologies such as WT and Ki67H may improve on the IHC4 concept with high inter-pathology reproducibility. We are currently validating in a larger 600 patient cohort. Citation Format: Barnes M, Srinivas C, Xu C, Dean S, Singh S, Henricksen LA, Wik N, Morris D, Magliocco A, LaFleur B. Early stage breast cancer prognostication using whole tumor or Ki67 heterogeneity-based digital imaging. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-01-04.

Abstract S3-01: EndoPredict (EPclin) score for estimating residual distant recurrence (DR) risk in ER+/HER2- breast cancer (br ca) patients treated with 5 years adjuvant endocrine therapy alone: Validation and comparison with the oncotype DX recurrence score (RS)

Abstract Background: RS is widely used for estimating 10-yr risk of DR for br ca patients receiving 5yrs adjuvant endocrine treatment alone. EndoPredict is a prognostic test which unlike RS combines its eight-gene expression signature (EP score) with tumor size and nodal status to provide the EPclin score with a single low/high risk cut-off at 10% risk of DR at 10yrs similar to the low/intermediate risk cut-off with RS. Aims: To determine the prognostic value of EP/EPclin over 10yrs, 0-5yrs and 5-10yrs in ER+/HER2- br ca patients and to compare this with the RS (i) alone (primary objective) and (ii) in addition to the clinical treatment score (CTS [developed in TransATAC]: nodes (N); tumour size; grade; age; tam or AI). Methods: mRNA from 928 ER+/HER2- primary br ca from patients treated with anastrozole or tamoxifen in the ATAC trial on which RS was already available were assessed for the EP/EPclin. Primary end point was DR. Kaplan–Meier and Cox regression analyses were used to determine DR risk for 0-10, 0-5 and 5-10yrs follow-up. Likelihood ratio tests (LR-chi sq) were used to assess the prognostic information provided by EP, EPclin, and RS alone and in combination with CTS. Results: Median follow-up was 9.95 yrs. The table shows the LR-chi sq for the prognostic information provided by each marker alone (univariate) and the information on top of CTS for all patients, and N- and N+ subgroups in 0-10, 0-5 and 5-10yrs. EP and EPclin provided substantially more prognostic information than RS across all three time periods and subgroups, except for N- patients in 0-5yrs. EP and EPclin also provided more information in addition to CTS than RS in 0-10yrs due to better performance of EP and EPclin in 5-10yrs where RS added no significant information to CTS. Using predefined cut-offs, EPclin and RS identified 546 (58.8%) and 573 (61.7%) patients as low risk respectively (HR (95%CI) low vs. non-low risk: 5.9 (3.9-9.1) and 2.7 (1.9-3.8), respectively). The EP score significantly added prognostic information to the RS over 0-10yrs and 5-10yrs in the overall, N- and N+ populations. Cases classified discordantly by EPclin and RS followed the EPclin classification more closely than RS classification. Prognostic information from EP, EPClin, RSLR-chi-sqAll patientsNode-negativeNode-positiveUnivariate0-10yrs0-5; 5-10yrs0-10yrs0-5; 5-10yrs0-10yrs0-5; 5-10yrsEP49.325.7; 23.630.811.9; 15.614.57.9; 6.6EPclin139.380.0; 59.340.017.0; 22.748.332.2; 16.1RS29.126.1; 5.621.318.7; 4.88.08.0; 1.0CTS149.885.0; 64.735.619.0;16.961.635.2; 26.3added to CTS EP16.46.9; 9.815.55.2; 6.68.32.3; 3.4EPClin20.310.5; 9.917.03.6; 9.05.46.4; 2.3RS12.811.8; 2.318.78.1; 1.44.13.7; 0.7LR-chi sq >3.8, p<0.05 Conclusions: EPclin was highly prognostic for DR in all patients, N-, N+, early and late metastasis. EPclin provided more prognostic information than RS in part but not solely because of the integration of the EP score with N and tumour size parameters. The data stress the importance of including clinicopathological factors in deriving an overall estimate of risk. Citation Format: Dowsett M, Sestak I, Buus R, Kronenwett R, Denkert C, Krappmann K, Scheer M, Petry C, Dubsky P, Cuzick J. EndoPredict (EPclin) score for estimating residual distant recurrence (DR) risk in ER+/HER2- breast cancer (br ca) patients treated with 5 years adjuvant endocrine therapy alone: Validation and comparison with the oncotype DX recurrence score (RS). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S3-01.

Identifying clinically relevant prognostic subgroups of postmenopausal women with node-positive hormone receptor-positive early-stage breast cancer treated with endocrine therapy: a combined analysis of ABCSG-8 and ATAC using the PAM50 risk of recurrence score and intrinsic subtype.

In the adjuvant treatment of hormone receptor-positive (HR+) breast cancer, variables like tumour size, grade and nodal status have great impact on therapy decisions. As most node-positive patients with HR+ breast cancer currently receive adjuvant chemotherapy improved methods for characterization of individuals' metastasis risk are needed to reduce overtreatment. Tissue specimens from node-positive patients of the ABCSG-8 and ATAC trials who received adjuvant tamoxifen and/or anastrozole were included in this study. Analysing RNA from paraffin blocks using the PAM50 test, the primary objective was to evaluate the prognostic information of the risk of recurrence (ROR) score added to combined clinical standard variables in patients with one positive node (1N+) and in patients with two or three positive nodes (2-3N+), using log-likelihood ratio tests. At a median follow-up of 9.6 years, distant metastases occurred in 97 (18%) of 543 node-positive patients. In a multivariate analysis, the PAM50-derived ROR score provided reliable prognostic information in addition to and beyond established clinical factors for 1N+ (P < 0.0001) and 2-3N+ patients (P = 0.0002). Ten-year distant recurrence risk was significantly increased in the high-risk compared with the low-risk group derived from ROR score for 1N+ [25.5%, 95% confidence interval (CI) 17.5% to 36.1%versus 6.6%, 95% CI 3.3% to 12.8%] and compared with the combined low/intermediate risk group for 2-3N+ patients (33.7%, 95% CI 25.5% to 43.8% versus 12.5%, 95% CI 6.6% to 22.8%). Additionally, the luminal A intrinsic subtype (IS) exhibited significantly lower risk of distant recurrence compared with the luminal B subtype in 1N+ and 2-3N+ patients. PAM50 ROR score and IS can identify node-positive patient subgroups with limited risk of metastasis after endocrine therapy, for whom adjuvant chemotherapy can be spared. The PAM50 test is a valuable tool in determining treatment of node-positive early-stage breast cancer patients.

Progesterone receptor A predominance is a discriminator of benefit from endocrine therapy in the ATAC trial.

Progesterone receptor (PR) function, while essential in normal human breast, is also implicated in breast cancer risk. The two progesterone receptors, PRA and PRB, are co-expressed at equivalent levels in normal breast, but early in carcinogenesis normal levels of PRA:PRB are frequently disrupted, and predominance of one isoform, usually PRA, results. In model systems, PRA and PRB have different activities, and altering the PRA:PRB ratio in cell lines alters PR signaling. The purpose of this study was to determine whether hormonal or reproductive factors contribute to imbalanced PRA:PRB expression in breast tumors and the impact of PRA:PRB imbalance on disease outcome. The relative expression of PRA and PRB proteins was determined by dual immunofluorescence histochemistry in archival breast tumors and associations with clinical and reproductive history assessed. PRA:PRB expression was not influenced by reproductive factors, whereas exogenous hormone use (menopausal hormone treatment, MHT) favored PRB expression (p < 0.035). The PRA:PRB ratio may be a discriminator of response to endocrine therapy in the TransATAC sample collection, with high PRA:PRB ratio predicting earlier relapse for women on tamoxifen, but not anastrozole (mean lnPRA:PRB ratio; HR (95 % CI) tamoxifen 2.45 (1.20-4.99); p value 0.02; anastrozole 0.80 (0.36-1.78); p value 0.60). The results of this study show that PRA:PRB imbalance in breast cancers is not associated with lifetime endogenous endocrine and reproductive factors, but is associated with MHT use, and that PRA predominance can discriminate those women who will relapse earlier on tamoxifen treatment. These data support a role for imbalanced PRA:PRB expression in breast cancer progression and relative benefit from endocrine treatment.

Predicting distant recurrence in receptor-positive breast cancer patients with limited clinicopathological risk: using the PAM50 Risk of Recurrence score in 1478 postmenopausal patients of the ABCSG-8 trial treated with adjuvant endocrine therapy alone

PAM50 is a 50-gene test that is designed to identify intrinsic breast cancer subtypes and generate a Risk of Recurrence (ROR) score. It has been developed to be carried out in qualified routine hospital pathology laboratories. One thousand four hundred seventy-eight postmenopausal women with estrogen receptor (ER)+ early breast cancer (EBC) treated with tamoxifen or tamoxifen followed by anastrozole from the prospective randomized ABCSG-8 trial were entered into this study. Patients did not receive adjuvant chemotherapy. RNA was extracted from paraffin blocks and analyzed using the PAM50 test. Both intrinsic subtype (luminal A/B, HER2-enriched, basal-like) and ROR score were calculated. The primary analysis was designed to test whether the continuous ROR score adds prognostic value in predicting distant recurrence (DR) over and above standard clinical variables. In all tested subgroups, ROR score significantly adds prognostic information to the clinical predictor (P<0.0001). PAM50 assigns an intrinsic subtype to all cases, and the luminal A cohort had a significantly lower ROR at 10 years compared with Luminal B (P<0.0001). Significant and clinically relevant discrimination between low- and high-risk groups occurred also within all tested subgroups. The results of the primary analysis, in combination with recently published results from the ATAC trial, constitute Level 1 evidence for clinical validity of the PAM50 test for predicting the risk of DR in postmenopausal women with ER+ EBC. A 10-year metastasis risk of <3.5% in the ROR low category makes it unlikely that additional chemotherapy would improve this outcome-this finding could help to avoid unwarranted overtreatment. ABCSG 8: NCT00291759.

Abstract P1-13-07: Chemotherapy, but not body mass index has impact on joint symptoms in postmenopausal Japanese breast cancer patients treated with anastrozole: A prospective multicenter cohort study of patient-reported outcomes

Abstract Background: Endocrine treatment-related adverse events have a strong impact on patients’ quality of life and sometimes result in treatment discontinuation. Since joint symptoms are the most frequently recognized side-effect of aromatase inhibitors, evaluation of associated risk factors may well be important. Among high body mass index (BMI) and chemotherapy have been associated with the development of joint symptoms in patients enrolled in ATAC trials. To determine the impact of these factors on treatment-emergent joint symptoms in Japanese breast cancer treated with adjuvant anastrozole, we conducted a prospective cohort study based on patient-reported outcomes (PROs). Patients and Methods: Postmenopausal Japanese women with estrogen receptor-positive breast cancer and treated with adjuvant anastrozole were enrolled in this prospective cohort study (SAVS-JP, UMIN000002455). A total of 416 patients were recruited from 30 centers for PRO assessment at their after-care appointments between August 2009 and April 2012. Patients completed the self-report questionnaire at baseline, 3, 6, 9 and 12 months. Symptoms were assessed as four categories (none, Grade 1: somewhat, Grade 2: quite a bit, Grade 3: very much). Pre-existing symptoms were only included if they worsened from baseline. The endpoint of this study was the frequencies of treatment-related joint symptoms, which included reports of arthralgia, decrease of joint motion, and joint stiffness. Results: We obtained PROs from 391 (94.0%) of the 416 patients at baseline and at one or more points during treatment, so that 391 patients were analysed. Joint symptoms at baseline were reported by 134 (34.3%) patients and new or worsening symptoms were experienced by 258 (66.0%) patients. The symptoms were graded as: grade 1, 53.1%; grade 2, 37.6%; grade 3, 9.3%. Mean time to onset of joint symptoms was 5.4 months, and nearly 80% had developed symptoms by 6 months. Twelve patents discontinued treatment during the first year and two patients withdrew due to joint symptoms. Patients with joint symptoms were significantly younger (age: 63.1; standard deviation: 7.9) than those without symptoms (age: 65.8: 8.4; p = 0.0045). We categorized BMI into three groups (low: &amp;lt;25, intermediate: 25-30, high: 30mg/m2&amp;lt;), but there were no significant relationships between BMI and joint symptoms. While joint symptoms were not significantly associated with neoadjuvant chemotherapy, patients treated with adjuvant chemotherapy (68 patients) reported a significantly higher frequency than did those not treated with adjuvant chemotherapy (83.8% vs 63.0%; p = 0.001). Discussion: The incidence of anastrozole-associated joint symptoms was more than 60%, with most women having developed symptoms by 6 months. The PROs may disclose higher prevalence rates than physician ratings for symptoms published in pivotal clinical trials. We found that younger age and adjuvant chemotherapy, but not high BMI, were significantly associated with joint symptoms. These data should prove useful for counseling before initiating treatment with adjuvant aromatase inhibitors for postmenopausal Japanese women. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-13-07.

CYP2D6 genotype in relation to tamoxifen efficacy in a Dutch cohort of the tamoxifen exemestane adjuvant multinational (TEAM) trial

The clinical importance of CYP2D6 genotype as predictor of tamoxifen efficacy is still unclear. Recent genotyping studies on CYP2D6 using DNA derived from tumor blocks have been criticized because loss of heterozygosity (LOH) in tumors may lead to false genotype assignment. Postmenopausal early breast cancer patients who were randomized to receive tamoxifen, followed by exemestane in a large randomized controlled trial were genotyped for five CYP2D6 alleles. CYP2D6 genotypes and phenotypes were related to disease-free survival during tamoxifen use (DFS-t) in 731 patients. By analyzing microsatellites flanking the CYP2D6 gene, patients whose genotyping results were potentially affected by LOH were excluded. In addition, exploratory analyses on 24 genetic variants of other metabolic enzymes and the estrogen receptor were performed. For the CYP2D6 analysis, only 2.3% of the samples were excluded, because influence of LOH could not be ruled out. No association was found between the CYP2D6 genotype or predicted phenotype and DFS-t (poor vs. extensive metabolizers: unadjusted hazard ratio 1.33, 95% CI 0.52-3.43; P=0.55). DFS-t was associated with UGT2B15*2 (Vt/Vt+Wt/Vt vs. Wt/Wt: adjusted hazard ratio 0.47, 95% CI 0.25-0.89; P=0.019) and the estrogen receptor-1 polymorphism ESR1 PvuII (gene-dose effect: adjusted hazard ratio 1.63, 95% CI 1.04-2.54; P=0.033). In postmenopausal early breast cancer patients treated with adjuvant tamoxifen followed by exemestane neither CYP2D6 genotype nor phenotype did affect DFS-t. This is in accordance with two recent studies in the BIG1-98 and ATAC trials. Our study is the first CYP2D6 association study using DNA from paraffin-embedded tumor tissue in which potentially false interpretation of genotyping results because of LOH was excluded. Polymorphisms in the estrogen receptor-1 and UGT2B15 may be associated with tamoxifen efficacy, but these findings need replication.

Comparison of PAM50 Risk of Recurrence Score With Oncotype DX and IHC4 for Predicting Risk of Distant Recurrence After Endocrine Therapy

Risk of distant recurrence (DR) among women with estrogen receptor (ER) -positive early breast cancer is the major determinant of recommendations for or against chemotherapy. It is frequently estimated using the Oncotype DX recurrence score (RS). The PAM50 risk of recurrence (ROR) score provides an alternative approach, which also identifies intrinsic subtypes. mRNA from 1,017 patients with ER-positive primary breast cancer treated with anastrozole or tamoxifen in the ATAC trial was assessed for ROR using the NanoString nCounter. Likelihood ratio (LR) tests and concordance indices (c indices) were used to assess the prognostic information provided beyond that of a clinical treatment score (CTS) by RS, ROR, or IHC4, an index of DR risk derived from immunohistochemical assessment of ER, progesterone receptor, human epidermal growth factor receptor 2 (HER2), and Ki67. ROR added significant prognostic information beyond CTS in all patients (Δ LR-χ(2) = 33.9; P < .001) and in all four subgroups: node negative, node positive, HER2 negative, and HER2 negative/node negative; more information was added by ROR than by RS. C indices in the HER2-negative/node-negative subgroup were 0.73, 0.76, and 0.78 for CTS, CTS plus RS, and CTS plus ROR, respectively. More patients were scored as high risk and fewer as intermediate risk by ROR than by RS. Relatively similar prognostic information was added by ROR and IHC4 in all patients but more by ROR in the HER2-negative/node-negative group. ROR provides more prognostic information in endocrine-treated patients with ER-positive, node-negative disease than RS, with better differentiation of intermediate- and higher-risk groups.

Immunohistochemical BAG1 expression improves the estimation of residual risk by IHC4 in postmenopausal patients treated with anastrazole or tamoxifen: a TransATAC study

BAG1 is a multifunctional anti-apoptotic protein located on chromosome 9q12, which binds to Bcl-2. BAG1 is present as a separate module in the GHI-RS 21-gene panel. It may provide additional prognostic information as an immunohistochemical marker when added to IHC4. Analysis of BAG1 was performed on archival tumour blocks from patients from the anastrozole and tamoxifen arms of the ATAC trial of 5years endocrine therapy in postmenopausal women with oestrogen receptor (ER)-positive primary breast cancer. Staining was scored separately as nuclear or cytoplasmic. Statistical analyses were performed on data from median 10-year follow-up with distant recurrence as primary endpoint. Data on both nuclear and cytoplasmic BAG1 as well as the IHC4 markers (ER, PgR, HER2 and Ki67) were available on 963 ER-positive cases of which 860 were HER2-negative. Cytoplasmic and nuclear BAG1 were highly correlated (Spearman r=0.79, p<00001). Women with higher BAG1 expression developed 30% fewer distant recurrences compared to those with low expression. Nuclear BAG1 contributed significantly to the clinical and IHC4 models with added information being greater in node-positive cases. Similar results were seen if all recurrences were the endpoints. BAG1 expression provides significant prognostic information when added to the classical clinicopathological parameters and IHC4, particularly in node-positive patients.

CYP2D6 genotype related to tamoxifen efficacy: An analysis with exclusion of potential false CYP2D6 genotype assignment caused by loss of heterozygosity in tumor tissue.

597 Background: The clinical importance of CYP2D6 genotype as predictor of tamoxifen efficacy is still unclear. Recent genotyping studies on CYP2D6 using DNA derived from tumor blocks have been criticized because loss of heterozygosity (LOH) in tumors may lead to false genotype assignment. Methods: Postmenopausal early breast cancer patients who were randomized to receive tamoxifen, followed by exemestane in the Tamoxifen Exemestane Adjuvant Multinational trial (TEAM) were genotyped for 5 CYP2D6 variant alleles. CYP2D6 genotypes and phenotypes were related to disease free survival during tamoxifen use (DFS-t) in 731 patients. By analyzing three microsatellites flanking the CYP2D6 gene, patients whose genotyping results were potentially affected by LOH were excluded. Results: Analysis of the CYP2D6 alleles and the microsatellite markers demonstrated heterozygosity for at least one of the CYP2D6 alleles or microsatellite markers in 97.7% of patients with a specified CYP2D6 phenotype. The 14 patients (2.3%) with a homozygous CYP2D6 genotype in which no heterozygosity could be demonstrated for the microsatellite markers were excluded from the analysis. No association was found between the CYP2D6 genotype or predicted phenotype and DFS-t. Conclusions: In postmenopausal early breast cancer patients treated with adjuvant tamoxifen followed by exemestane neither CYP2D6 genotype nor phenotype was associated with DFS-t. This is in accordance with two recent studies in the BIG1-98 and ATAC trials. Our study is the first CYP2D6 association study using DNA from paraffin embedded tumor tissue in which potentially false interpretation of genotyping results because of LOH was excluded.