Intermediate Recurrence Score Research Articles

Abstract PS16-10: SPATIAL IMMUNE CELL DISTRIBUTION CAN REFINE PROGNOSIS IN EARLY-STAGE ER+/HER2-/LN- BREAST CANCER

Abstract Lymphocytic infiltrate is a known prognostic biomarker in estrogen receptor(ER)-negative breast cancers (BCs). Comparatively ER+ disease is putatively cold, however, there exists an infiltrate-rich subset of ER+ tumours with significant spatial heterogeneity and unknown clinical impact. Using serial sections taken from early-stage, ER+/HER2- breast tumours of Irish patients enrolled in the TAILORx trial (n=450), we aimed to investigate the prognostic potential of markers encompassing tumour architecture. Immunohistochemistry for Ki67 and CD45 (leukocyte common-antigen), and staining for haematoxylin and eosin was applied to all sections [1]. Classifiers for stromal fraction (SF), stromal-infiltrate (sTIL), Ki67-LI, and their spatial relationships within the tumour were generated using QuPath [2] and R Studio. Trained marker classifiers were validated against an expert pathologist (R2 of M-Score to: CD45%: 0.968, Ki67-LI: 0.814, sTIL: 0.864) to define observed lymphocytes as tumour or stromal-infiltrating, retain only tumour Ki67+ density, and to investigate SF. Cohort mean SF was 67.69% (range 16.35 – 98.29%), with marginally significant differences in recurrence prediction for cohort high v low SF by mean (c-index = 0.58, p< 0.032), and luminal A disease (p=0.037) only. sTILs did not differ significantly between high/low mean SF (Mann-Whitney p=0.6201), though sTIL was prognostic in the OncotypeDx intermediate Recurrence Score (RS) category overall (p=0.0076). This trend appeared strongest in intermediate RS patients receiving chemo-endocrine therapy (HT+CT) (p < 0.0001) vs endocrine therapy (HT) alone (p=0.86). Investigating the effects of prescribed therapy on sTIL-derived recurrence risk also revealed significant trends in those patients receiving HT+CT only (p < 0.00001) vs HT alone (p=0.26). Spatial analysis of sTILs suggest that tumours become more immune excluded as Oncotype Dx RS increases - particularly from intermediate to high RS (Wilcoxon Intermediate v High: p=0.0077), with significant differences in survival for high/low tumour-immune hotspots observed in Intermediate RS, HT+CT treated patients (p=0.0052). Further spatial analysis suggests that high normalised frequency of infiltrate [method adapted from 3] (within 7um of tumour cells) have negative prognostic impact for premenopausal patients (p=0.017), and inter-sectional analysis identifies niche tumour environments where high Ki67-LI colocalize with immune infiltrates[methods adapted from 4, 5], most notable in Intermediate RS tumours.. Overall these data suggest immune-spatial subsets can be used to refine risk stratification of ER+ breast cancer.

Abstract PO1-14-12: Quantitative Biomarkers and 21-Gene Assay Results Predict Breast-Conserving Surgery Following Neoadjuvant Therapy in Early-Stage, Hormone Receptor-Positive, HER2-Negative Breast Cancer

Abstract Background: Neoadjuvant chemotherapy (NACT) and neoadjuvant endocrine therapy (NET) are often used to downstage tumors and/or enable breast-conserving surgery (BCS) in patients (pts) with early-stage, hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer. Given the increasing use of neoadjuvant therapy for HR+ breast cancer, studies are needed to better quantify the success of NACT/NET in downstaging tumors as a function of estrogen (ER), progesterone (PR), and Ki-67 expression, and 21-gene recurrence score (RS) in this patient population. Methods: Data were from pts with stage I-III, HR+/HER2- breast cancer diagnosed from 2010-2020 in the National Cancer Database (NCDB). Quantitative ER, PR, and Ki-67 data became available in 2018. We included pts who received either NACT or NET, with surgical plan categorized as mastectomy or BCS. Pts who received NACT for 12–30 weeks or NET for 4–36 months prior to surgery were eligible. Predicted rates of BCS by quantitative biomarkers (ER, PR, Ki-67 percentage, and RS) were estimated using restricted cubic spline logistic regression. Multivariable logistic regression models were fit to examine the associations between surgical plan and quantitative biomarkers for the two neoadjuvant cohorts. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were calculated per 10% increase in percentages of ER, PR, and Ki-67 expression. Results: Of 44,589 pts treated with NACT, the mean age was 53 years, the median amount of time they were on NACT before surgery was 21 weeks, and 65% had cT1-2 disease. Of 10,466 pts treated with NET, the mean age was 68 years, the median amount of time they were on NET before surgery was 6 months, and 76% had cT1-2 disease. Overall, 42% of pts underwent BCS after NACT; while 64% did after NET. In the NACT cohort, 13,752 of the pts with available quantitative biomarker data were included in regression analyses; in the NET cohort, 4,003 were included. After adjusting for demographic and clinicopathologic factors, increasing ER% (aOR=0.96, 95% CI: 0.94–0.97) and PR% (aOR=0.98, 95% CI: 0.96–0.99) were associated with lower odds of BCS after NACT. Increasing Ki-67% was associated with greater odds of BCS after NACT (aOR=1.07, 95% CI: 1.04–1.10). Pts with a low (aOR=0.50, 95% CI: 0.29–0.88) or intermediate (aOR=0.58, 95% CI: 0.41–0.81) RS were significantly less likely than pts with a high RS to undergo BCS after NACT. Asian pts were less likely than White pts to have BCS (aOR=0.75, 95% CI: 0.56–0.99), while rates of BCS after NACT were similar to pts from other racial and ethnic groups. In the NET cohort, increasing ER% was associated with greater odds of BCS (aOR=1.09, 95% CI: 1.01–1.17). There was no significant association between baseline PR% or Ki-67% and BCS after NET. Pts with a low (aOR=0.92, 95% CI: 0.60–1.43) or intermediate (aOR=0.96, 95% CI: 0.65–1.41) RS were numerically less likely than pts with a high RS to have BCS after NET, though not statistically significant. Compared with White pts, Asian pts were less likely to have BCS after NET (aOR=0.60, 95% CI: 0.40–0.91). Conclusions: In this analysis of pts from the NCDB who received neoadjuvant therapy for early-stage, HR+/HER2- breast cancer, we found that BCS after NACT was higher for patients with a high RS or high Ki-67, suggesting that NACT is unlikely to downstage tumors with a low/intermediate RS or low Ki-67. Most pts receiving NET underwent BCS (likely due to a smaller clinical tumor size); BCT after NET was most dependent on ER expression. Asian pts were less likely to undergo BCS after either NACT or NET, which is consistent with previous reports. These data could facilitate appropriate neoadjuvant treatment selection based on tumor biology and improve patient counseling on the likelihood of successful BCS. Citation Format: Jincong Freeman, Sarah Shubeck, Nan Chen, Rita Nanda, Dezheng Huo, Frederick Howard. Quantitative Biomarkers and 21-Gene Assay Results Predict Breast-Conserving Surgery Following Neoadjuvant Therapy in Early-Stage, Hormone Receptor-Positive, HER2-Negative Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-14-12.

Abstract PO1-14-02: Real world application of a 21-gene recurrence score in a Swiss single center breast cancer population. A comparative analysis of treatment administration before and after TAILORx

Abstract TAILORx was published in July 2018 and showed benefit of chemotherapy (CHT) in premenopausal, HER2 negative breast cancer (BC) patients with a 21-gene intermediate recurrence score (RS). The aim of this study was to determine treatment patterns before and after publication of TAILORx at our Swiss BC center. This is a retrospective analysis of 326 estrogen receptor positive (ER+)/HER2 negative BC patients, treated at Basel University Hospital and Cantonal Hospital Baselland from 2010-2021. Primary endpoint was to assess change in therapy before (cohort A) and after the publication of TAILORx (cohort B) when adjusted for RS category thresholds as defined by the manufacturer and as modified in the TAILORx study protocol. Secondary endpoint was to determine main therapy decision factors. There were no significant differences in the two populations. A included 165 and B 161 patients with a mean RS of 17.72 and 17.89 (p=0.87) respectively. No differences were noted in terms of demographics or tumor characteristics between the two groups. Mean age in A was 58.8 and in B 57.7 years old. There was a tendency for higher ASA scores in B (p=0.262) and higher BMIs in A (p=0.612). There were no differences in RS distribution between A and B when adjusted to manufacturer’s thresholds (p=0.15 for low RS, 0.833 for intermediate and 0.15 for high RS), and subsequently to TAILORx thresholds for RS categories (p=0.817 for low RS, 0.199 for intermediate and 0.795 for high RS). There was no difference in the 2 populations with regards to number of positive nodes (p=0.366) and pN status (p=0.903). In the intermediate node negative population, there were 67 patients in A and 55 in B. No significant differences were noted in demographics (median age 58.9 years in A and 57.2 years in B, p=0.414, menopausal status, p=0.806, relevant comorbidities in 28 patients in A and 21 in B, p=0.864). A relevant tendency for higher ASA scores in B was maintained in this subgroup, with a median score of 3 in B vs 2 in A, p=0.001). Mean tumor size was 20.73 mm in A and 21.17 mm in B (p=0.857) with a mean Ki67 of 20% in both A and B and more cases of higher Ki67 in B (40%) vs A (22%) but not significant (p=0.624). Mean RS was 17.43 in A and 17.75 in B (p=0.674). In the intermediate nodal negative subgroup, the majority had conservative breast surgery (64% in A and B), with less reconstruction in A vs B (46% vs 52%, p=0.031). Radiotherapy (RT) was administered in 66% of women in A and 69% in B (p=0.307) with a mean dose of 53.41 Gy in A and 50.75 Gy in B (p=0.153). Only 4 patients had CHT in A and one patient in B (p=0.775) with one case of severe CHT associated complications in A. Seven patients refuse CHT. In A 31% of patients and in B 44% had osteo-oncologic treatment (p=0.005). There are 7 cases of relapse in A and 3 in B (p=0.492) with one BC related death in A. Tumor board seems to weight more post TAILORx (82% of decision implementation in B vs 63% in A, p=0.38). In the whole population, RS influences decision in the low category, with 91% alignment of RS recommended treatment in A. In B there seem to be a tendency toward more hormonal therapy (138%) but no reduction in CHT application, while in A more patients were administered CHT than recommended by RS guidelines (181%, p< 0.001). Therapy decision is not influenced by demographic nor tumor characteristics in A nor B, and there are no differences in surgery (68.4% in A and 64% in B, p=0.352), endocrine therapy (65.4% in A vs. 52% in p=0.113), RT (78% in A and 76% in B, p=0.223). At a median follow up of 62.9 months in A and 19.5 in B, relapse was higher in A (19) vs B (5) (p< 0.001) with 5 deaths in A vs none in B. However due to study design which implies different dates of inclusion in the analysis, as well as limited number of events, this data has no power. Before TAILORx decision was mainly dependent on tumor features. After TAILORx other factors, which are particular to every case weight more. This data shows that therapy decisions are not particularly shifted after TAILORx, confirming the emergence of personalised medicine. Demographics, Tumor Characteristics, Therapy and Outcome, RS Categories Thresholds in two Cohorts before and after Publication of TAILORx. What changed? Citation Format: Elena D Chiru, Cvetka Grasic Kuhar, Christian Kurzeder, Marcus Vetter. Real world application of a 21-gene recurrence score in a Swiss single center breast cancer population. A comparative analysis of treatment administration before and after TAILORx [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-14-02.

Abstract 4975: Stretching the boundary of Oncotype DX testing

Abstract Background: The predictive value of Oncotype DX in early-stage breast cancer had been well established. Strongest data support the use of chemotherapy for Recurrence Score (RS) > 30, with 25-30 deriving some benefit. Those with intermediate RS 16-25 are thought to have a small benefit from chemotherapy, especially premenopausal patients. Tumor size >5 cm is viewed as a high-risk feature regardless of RS. Our goal is to investigate how patients with uncertainty regarding their anticipated recurrence risk were managed at our institution. Methods: We conducted a retrospective analysis to explore the management of non-metastatic HER-2 negative hormone sensitive breast cancer patients diagnosed between 01/2018 &12/2020 stratifying them into the following study groups of interest: premenopausal (age <50), RS 16-25 compared to RS 26-30 and tumor size >5cm. Patients were compared based on whether they received adjuvant chemotherapy or not. The primary endpoint was the rate of local recurrence. Results: The results of our analysis are illustrated in the table. Studying the premenopausal group, 91.3% had RS < 16; yet 35% of them received chemotherapy. Patients with RS > 25 represented 3.2% of the premenopausal group, 12.5% of which did not receive chemotherapy. The six recurrences in the premenopausal group were all from the RS <16 subgroup. Comparing the RS 26-30 to the RS 16-25 group, patients were on average older with tumors being on average smaller, yet more patients were treated with chemotherapy; and there were no recurrences noted in both subgroups. Finally, in the tumor size >5 cm group, 91.4% had RS <16, almost all were premenopausal with many patients being lymph node negative, yet more than half received chemotherapy. Conclusions: In our study we demonstrate that in certain subgroups of early-stage breast cancer there is inconsistency in clinical practice when prescribing chemotherapy to patients factoring in their Oncotype DX scores. There is need for larger trials to guide clinicians on using Oncotype DX in those subgroups of patients. Characteristics, Treatment Pattern and Outcomes of Patient Groups of Interest Characteristics Premenopausal (N=506) RS 16-25 (N=28) RS 26-30 (N=36) Tumor Size >5 cm (N=47) Age, Mean (SD) 42.65 (5.46) 44.71 (3.85) 63.56 (9.65) 42.02 (6.14) Age, Range 19 - 49 36 - 49 45 - 79 28 - 57 Mean Tumor Size, mm (SD) 29.66 (52.21) 29.57 (33.88) 16.88 (11.19) 83.61 (37.52) Lymph Nodes Positive, n (%) 91 (18.0%) 2 (7.1%) 0 (0.0%) 16 (34.0%) Received Chemotherapy, n (%) 184 (36.4%) 7 (25.0%) 13 (36.1%) 25 (53.2%) Local Recurrence, n (%) 6 (1.2%) 0 (0.0%) 0 (0.0%) 0 (0.0%) Mean Follow- Up, months (SD) 19.28 (8.20) 19.39 (7.07) 21.21 (11.04) 19.26 (8.93) Citation Format: Zaid Al-Saheli, Vrushali Dabak. Stretching the boundary of Oncotype DX testing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4975.

Adjuvant Chemotherapy in Premenopausal Patients With Hormone-Positive Breast Cancer With a Recurrence Score of 16-25: A Retrospective Analysis Using the National Cancer Database.

Results from the TAILORx trial revealed that the use of adjuvant chemotherapy along with endocrine therapy had no survival advantage in patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2-negative (HER2-), node-negative (N0) breast cancer (BC) with an intermediate (11-25) 21-gene recurrence score (RS) in the overall population. However, in patients under age 50 years, adjuvant chemotherapy demonstrated a progression-free survival benefit when the RS ranged from 16-25. We studied this cohort with the population-based national database. The 2010-2018 National Cancer Database was used to include patients with BC age 18-50 years, N0, M0, RS 16-25, ER+/progesterone receptor±, and HER2-. Patients were divided into two groups on the basis of adjuvant chemotherapy use, and the survival between them was compared. Adjuvant chemotherapy use was noted in 4,808/15,792 (30.45%) patients. Median RS was 18 and 21 in patients without and with adjuvant chemotherapy, respectively. Factors associated with adjuvant chemotherapy use were higher T stage, poor and moderately differentiated tumors, age <40 years, care at an academic center, Caucasian race, patients undergoing mastectomy, regional lymph node surgery, and radiation therapy. Kaplan-Meier survival at 10 years was better with adjuvant chemotherapy (96.2% v 91.6%). Patients without adjuvant chemotherapy had more adverse outcomes (hazard ratio [HR], 1.683 [95% CI, 1.392 to 2.036]; P < .0001). Subgroup analysis showed that the benefit was significant in patients with RS scores 21-25 (HR, 1.953 [95% CI, 1.295 to 2.945]), ductal histology (HR, 1.521 [95% CI, 1.092 to 2.118]), Caucasian race (HR, 1.655 [95% CI, 1.180 to 2.322]), and 41-50 years age group (HR, 1.732 [95% CI, 1.244 to 2.411]). Our study showed an overall survival benefit for adjuvant chemotherapy use in patients with ER-positive, N0 premenopausal BC patients, age less than 50 years, with an intermediate RS score, particularly 21-25.

Increased PI3K pathway activity is associated with recurrent breast cancer in patients with low and intermediate 21-gene recurrence score

AimsWe investigated key signalling pathways’ activity and mutational status of early-stage breast carcinomas with low and intermediate 21-gene recurrence score (RS) to identify molecular features that may predict recurrence.MethodsThis is...

Treatment outcomes in patients with discordant recurrence score and RSClin risk predictions.

574 Background: Guidelines recommend the use of genomic assays to aid decision making regarding the use of adjuvant chemotherapy (CT) for hormone receptor-positive, HER2-negative (HR+/HER2-) early breast cancer (EBC). Recently, the RSClin tool, which integrates the 21-gene recurrence score (RS) and clinicopathologic features, was developed to better estimate CT benefit. Here, we studied patients with RSClin/RS discordance to determine if patients (pts) should be treated according to RS or RSClin. Methods: This was a retrospective cohort study of pts from the National Cancer Database who were diagnosed with HR+/HER2- node negative EBC from 2010-2020 who underwent RS testing and received adjuvant endocrine therapy with or without CT. Pts were classified as low RS ( &lt; 26) or high RS (≥ 26) and low ( &lt; 3%) versus high (≥ 3%) predicted CT benefit per RSClin. The primary outcome was overall survival (OS) benefit associated with CT administration for pts with discordant RS/RSClin, measured as hazard ratio [HR] for receipt of CT. Hazard ratios were adjusted for age and comorbidity index, and inverse probability of treatment weighting was performed for age, comorbidity index, race, ethnicity, and insurance status. Results: 262,748 pts with EBC were included, with a median follow-up of 58 months. Median age was 60 years; 82% were White, 7% Black, 5% Hispanic, and 4% Asian/Pacific Islander. Median tumor size was 1.5 cm, and median RS was 15. The 31,955 cases with concordant high RS/RSClin had an OS benefit with CT (HR: 0.71, 95% CI: 0.67 - 0.75, p &lt; 0.001), while the 206,631 cases with concordant low RS/RSClin did not have a survival benefit (HR: 1.00, 95% CI: 0.95 - 1.04, p = 0.85, Table). High RS with low RSClin was seen in 435 cases – all with grade 1 tumors, with RS no greater than 28, and tumor size under 1.3cm. No significant CT benefit was seen in this small subset of pts (HR 1.57, 95% CI 0.75 – 3.26, p = 0.23). In 23,727 pts with low RS but high RSClin, a CT benefit was seen (HR 0.73, 95% CI 0.67 – 0.78, p &lt; 0.001). These pts had high-intermediate RS (median 23, interquartile range 20 – 24) with other higher risk features. Similar results were seen in older (age &gt; 50) and younger (age ≤ 50) subgroups – although no pts ≤ 50 were in the low RS/high RSClin group. Conclusions: RSClin may identify a small number of grade 1 tumors with high RS for which CT is not needed, and may help guide appropriate use of CT for EBC in the sizeable group with intermediate RS. [Table: see text]

Correlation between Magee score and recurrence score in Indian patients with breast cancer.

e12555 Background: Recurrence score (RS) from Oncotype Dx (ODx) test predict chemotherapy benefit in estrogen receptor (ER) positive, and HER2-negative patients with breast cancer. ODx is an expensive test in an Indian practice setting - cost of adjuvant chemotherapy is one-sixth of the cost of the test. Magee equations use histopathological variables, and semiquantitative results from ER, PR and Ki-67, to calculate Magee score (MS) and provide a cost-effective surrogate mechanism for predicting RS. We aimed to assess the correlation between MS and RS in an Indian setting. Methods: Pathology reports were obtained from oncologists in India. Immunohistochemistry for ER and PR were reported using the Allred system. Therefore, two methods were identified to estimate H-scores - using a calculated method (A), and using an expert-approximated (B) method. MS were calculated by a single investigator blinded to the RS. MS and RS were then assessed for correlation via the Pearson correlation method. MS were arbitrarily stratified into ≤ 15, 15 - 30, and ≥ 30, and their overall agreement (OA) or concordance with RS risk categories, ≤ 15, 15 - 30, and ≥ 30, were assessed. The OA was assessed by determining the proportion of patients in similar risk categories across low, intermediate and high-risk RS and MS. Results: Among 34 patients included in the study, 38% (13) had an RS ≤ 15, 38% (13) had an RS between 15 and 30, and 23% (8) had an RS ≥ 30. Correlation coefficient between MS and RS was 0.78 for both methods of estimation (p&lt;0.0001). The OA between MS-A and RS, and MS-B and RS were 59% (20/34) and 47% (16/34) respectively. The concordance between low-risk MS-A and RS is 78% (n=9) and between low-risk MS-B and RS is 50% (n=20). The concordance between high-risk MS-A and RS is 100% (n=2) and high-risk MS-B and RS is 100% (n=2). Conclusions: Although there is good correlation between RS and MS, the concordance between the two in similar risk categories is not optimal. Of the two methods to estimate H-score from Allred score, the calculated method seems to be more optimal. Our pilot study shows good correlation between MS and RS. We recommend that pathologists incorporate H-score as part of the reporting of ER and PR. A larger prospective study will be useful to test our hypothesis for the use of MS as a predictive tool for adjuvant chemotherapy in breast cancer.

Abstract P1-04-09: Correlating Predicted Adjuvant Therapy Benefit and Risk of Recurrence between Breast Cancer Index (BCI) and 21-gene Oncotype DX Recurrence Score (RS)

Abstract Background: The 21-gene Recurrence Score (Oncotype DX) is a genomic assay that provides prognostic information for distant recurrence risk and is predictive of adjuvant chemotherapy benefit in hormone receptor (HR)-positive, HER-2 negative early-stage breast cancer (EBC). The Breast Cancer Index (BCI) is another molecular gene expression-based assay that evaluates the utility of extending adjuvant endocrine therapy (ET) from 5 to 10 years and predicts risk of distant recurrence. In January 2021, the National Comprehensive Cancer Network (NCCN) Guidelines added BCI to guide duration of adjuvant ET as a category 2A recommendation. The goal of this study was to evaluate the association between BCI and RS in terms of their predicted benefit for adjuvant therapy and risk of distant recurrence. We also assessed the association of various anatomic and biologic tumor features with BCI. Methods: We performed a retrospective chart review of all patients with HR-positive EBC who had a BCI and Oncotype DX performed between 2007-2021. Demographics, tumor characteristics and BCI and RS results were extracted from the electronic medical record. Patients were categorized by BCI predictive of extended ET (formerly BCI high) versus not (formerly BCI low) and RS of low (0-10), intermediate (11-25) and high (26-100). Numerical values for distant recurrence risk were recorded for both BCI and Oncotype DX tests. Multivariable regression models were used to assess the relationship between BCI and Oncotype DX as well as factors associated with each. Results: We identified 153 women with HR-positive EBC with both RS and BCI performed. The median age of the population was 57 years and 25% were premenopausal. 32% (n=49) had a BCI result predictive of benefit from extended adjuvant ET. When comparing patients with BCI predictive of extended ET versus those with BCI not predictive of extended ET, there was no association between BCI and RS based on multivariate logistic regression models, p=0.7. A similar distribution of RS was observed between patients who had a BCI result predictive of benefit from extended ET versus not predictive. Among 49 patients with a BCI predictive of extended ET, 35% had high RS, 63% intermediate RS and 2% low RS. Among 104 patients with a BCI not predictive of extended ET, 24%, 73% and 3% had high, intermediate, and low RS, respectively. Multivariate regression models revealed an association between poorly differentiated tumors and BCI result predictive of extended ET, p=0.002. No associations were observed between BCI and menopausal status, ER%, PR%, tumor size or lymph node positivity. Regarding risk of recurrence, there was an association between BCI and Oncotype DX in terms of their predicted numerical risk of recurrence, p&amp;lt; 0.001. Higher percentage of PR positivity, poorly differentiated tumors, and lymph node positivity were associated with a higher risk of recurrence on the BCI. Conclusions: In our patient population selected to have Oncotype DX and BCI performed, we found no association between the two genomic assays in terms of their predictive benefit. However, there was an association between Oncotype DX and BCI in terms of their prognostic ability. Given the increased use of BCI since its inclusion in national guidelines, it is important to understand its relationship with other genomic assays especially when used to guide clinical decisions and estimate prognosis. Citation Format: Rima Patel, Nicole Casasanta, Zhiqiang Li, Melanie Kier, Julia Blanter, Sophie Sohval, Malin Hovstadius, Catherine Wu, Marc Fink, Xiang Zhou, Brittney Zimmerman, Krystal Cascetta, Rong Chen, William Oh, Amy Tiersten. Correlating Predicted Adjuvant Therapy Benefit and Risk of Recurrence between Breast Cancer Index (BCI) and 21-gene Oncotype DX Recurrence Score (RS) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-04-09.

Abstract P2-03-06: Real world treatment of node negative low and intermediate recurrence score breast cancer

Abstract Introduction: Patients younger than 50 years old with node negative hormone receptor (HR) positive her2 negative breast cancer and oncotype Dx recurrence scores (RS) under 16 do not benefit from adjuvant chemotherapy. Those with a RS between 16-25 may have a marginal benefit from the addition of adjuvant chemotherapy, however a similar benefit may be achieved with adjuvant ovarian function suppression (OFS). The aim of this study is to describe real world treatment patterns and outcomes of premenopausal node negative patients with low and intermediate RS, with an emphasis on adjuvant OFS, endocrine therapy (ET), and menopausal status during adjuvant treatment. Methods: We retrospectively reviewed the records of all node negative patients under 50 years old who were sent for oncotype testing between 2008 and 2018. One hundred and sixty-five patients with low or intermediate RS were included in our analysis. Continuous variables were described using medians and interquartile range (IQR). Categorical variables were described as frequencies and percentages. Differences between categorical variables were analyzed with the chi squared test and survival was analyzed using the Kaplan-Meier method. The cox proportional hazards model was used to test the effect of multiple factors on survival. Breast cancer specific survival (bcss) was defined as the time to first breast cancer recurrence (local recurrence, second breast cancer, distant recurrence) and distant disease-free survival (ddfs) was defined as the time to any distant recurrence. Results: The median age was 44 (41-47) and median RS was 17 (14-20). Median follow-up time was 82 (61-108) months. One hundred and three (62.4%) patients had low clinical risk as defined in TailorX and 136 (82.4%) had intermediate RS. Fourteen (8.5%) patients with nodal micrometastases were also included. Only 5 (3%) patients received adjuvant chemotherapy and 74 (44.8%) received adjuvant OFS. Of the 91 (55%) of patients who did not received OFS, 21 (23%) went into menopause or underwent subsequent oopherectomy while on adjuvant ET. One hundred and three (62.4%) patients received adjuvant tamoxifen alone, 16 (9.7%) received an aromatase inhibitor alone, and 40 (24.2%) underwent an endocrine switch with all but 1 beginning treatment with tamoxifen. There were no significant differences in clinical risk or RS risk group between patients that received and did not receive OFS. There were 22 (13.3%) bcss recurrences. Twelve (7.2%) patients had a local recurrence, 5 (3%) patients had second breast cancers, and 5 (3%) had a distant recurrence as their first recurrence. Overall, only 6 (3.6%) patients had a distant recurrence. Both OFS and ET type were not significantly associated with bcss or ddfs. On univariate analysis menopause during ET was significantly associated with improved bcss (HR= 0.2, 95% CI 0.05-0.85), however on multivariate analysis it was no longer significant. Conclusion: With only 6 (3.6%) distant recurrences over a median follow-up of over 6.5 years node negative premenopausal women with low or intermediate RS treated in our institution show an excellent prognosis regardless of treatment type. Our results support the evidence that most of these patients do not need chemotherapy and suggests that most patients do not require OFS as well. Additional data examining the relationship between gene expression profiles and OFS benefit are needed to help guide OFS treatment in premenopausal patients who do not require chemotherapy. Citation Format: Opher Globus, Keren Levanon, Einav Nili-Gal Yam. Real world treatment of node negative low and intermediate recurrence score breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-03-06.

Abstract P3-05-27: The impact of co-existing ductal carcinoma in situ in invasive early hormone receptor positive breast cancer on the genomic and clinical risk of recurrence

Abstract Background: Invasive early breast cancer (IBC) often presents with a co-existing ductal carcinoma in situ (DCIS) component, while about 5% of the cases present with an extensive (&amp;gt;25%) intraductal component (EIC). The presence of a DCIS component was previously shown to be associated with favorable clinico-pathological characteristics and survival outcomes. However, the association between co-existing DCIS and genomic risk of recurrence is unclear. Methods: Patients with early hormone receptor positive (HR+) HER2neu-negative (HER2-) breast cancer and known OncotypeDX breast recurrence score (RS), who underwent breast surgery in our institute, were included. A natural language processing (NLP) algorithm was used to identify co-existence of extensive DCIS (DCIS-H) and non-extensive DCIS (DCIS-L) in surgical pathological reports. Genomic risk was determined using OncotypeDX RS, while clinical risk was calculated according to the MINDACT criteria, based on tumor size and grade. The genomic and clinical risks of DCIS-H, DCIS-L and pure IBC (No-DCIS) were compared. Results: A total of 45 (5%) DCIS-H cases, 468 (56%) DCIS-L cases and 328 (39%) No-DCIS cases were identified. DCIS-H cases presented with less aggressive clinico-pathological characteristics, such as lower proportions of histologic grade III (10% vs 26% vs 21%) and lower proportions of node-positive disease (13% vs 18% vs 21%), compared to DCIS-L and No-DCIS cases, respectively. The distribution of OncotypeDX RS significantly varied between the groups. DCIS-H tumors were less likely to have a high RS and more likely to have a low or intermediate RS compared to DCIS-L and No-DCIS tumors (High RS: 4% vs 20% vs 20%, Low + intermediate RS: 96% vs 80% vs 80%, respectively; p=0.04). Additionally, the proportions of high clinical risk cases were lower in the DCIS-H group compared to the DCIS-L and No-DCIS groups (42% vs 53% vs 50%, respectively; p=0.002). Based on genomic and clinical risk and current guidelines, we found that women presented with an extensive DCIS component (DCIS-H) had a lower probability of receiving an adjuvant chemotherapy recommendation compared to women presented with a non-extensive DCIS component (DCIS-L) or pure IBC (No-DCIS) (11% vs 29% vs 25%, respectively; p=.035). No differences in disease recurrence were detected between the groups. Conclusions: Co-existing extensive DCIS in invasive early HR+Her2- breast cancer is significantly correlated with lower genomic and clinical risk of recurrence and a smaller chance for chemotherapy recommendation. The rarity of this condition (5% of cases) limited our ability to detect differences in outcomes. These findings warrant future studies of the underlying genomic landscape of co-existing extensive DCIS. Citation Format: Yael Bar, Kfir Bar, Judith Ben- Dror, Didi Feldman, Meishar Shahoha, Ahuva Weiss-Meilik, Nachum Dershowitz, Wolf Ido, Amir Sonnenblick. The impact of co-existing ductal carcinoma in situ in invasive early hormone receptor positive breast cancer on the genomic and clinical risk of recurrence [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-27.

Evaluation oncotype DX® 21-gene recurrence score andclinicopathological parameters: a single institutional experience.

Oncotype DX recurrence score (RS) is a clinically validated assay, which predicts the likelihood of disease recurrence in oestrogen receptor-positive/HER2-negative (ER+/HER2-) breast cancer (BC). In this study we aimed to compare the performance of Oncotype DX against the conventional clinicopathological parameters using a large BC cohort diagnosed in a single institution. A cohort (n= 430) of ER+/HER2- BC patients who were diagnosed at the Nottingham University Hospitals NHS Trust and had Oncotype DX testing was included. Correlation with the clinicopathological and other biomarkers, including the proliferation index, was analysed. The median Oncotype DX RS was 17.5 (range=0-69). There was a significant association between high RS and grade 3 tumours. No grade 1BC or grade 2 tumours with mitosis score 1 showed high RS. Low RS was significantly associated with special tumour types where none of the patients with classical lobular or tubular carcinomas had a high RS. There was an inverse association between RS and levels of ER and progesterone receptor (PR) expression and a positive linear correlation with Ki67 labelling index. Notably, six patients who developed recurrence had an intermediate RS; however, four of these six cases (67%) were identified as high-risk disease when the conventional clinical and molecular parameters were considered. Oncotype DX RS is correlated strongly with the conventional clinicopathological parameters in BC. Some tumour features such as tumour grade, type, PR status and Ki67 index can be used as surrogate markers in certain scenarios.

Survival Benefit of Chemotherapy According to 21-Gene Recurrence Score in Young Women with Breast Cancer.

Initial trials evaluating Oncotype DX, reported as a recurrence score (RS) from 0 to 100, were not powered to evaluate overall survival, and premenopausal women were underrepresented. The purpose of this study was to explore the benefit of chemotherapy according to RS among younger women eligible for oncotype testing. Women aged 40-50, diagnosed with HR-positive, HER2-negative breast cancer between 2010 and 2017 were selected from the National Cancer Database (NCBD). Patients were grouped by age, RS, nodal status, and chemotherapy receipt. Kaplan-Meier curves were used to compare unadjusted overall survival (OS) between the groups, and log-rank tests were used to test for a difference between groups. Cox proportional hazards models were used to examine the association between select factors and OS. A total of 15,422 patients met inclusion criteria, 45.3% of whom received chemotherapy. Median follow-up time was 66.4 (50.6-86.6) months. Patients who received chemotherapy were more likely to have higher-stage and higher-grade tumors, tumors that were PR-negative, and have higher RS (p < 0.001 for all). RS was prognostic for OS regardless of nodal status. After adjustment, chemotherapy was associated with a significant improvement in OS only in the pN1 RS 31-50 subgroup (p = 0.02). RS retains its prognostic value in younger patients with early stage HR-positive, HER2-negative breast cancer. Chemotherapy survival benefit was limited to patients aged 40-50 with pN1 disease and RS of 31-50. Therefore, chemotherapy decision-making should be especially preference-sensitive in women aged 40-50 with intermediate RS, where it may not provide a survival benefit for many women.

Correlation of the Ki67 Working Group prognostic risk categories with the Oncotype DX Recurrence Score in early breast cancer.

The relationship between Ki67 assessed by immunohistochemistry (IHC) and the Oncotype DX Recurrence Score (RS) is unclear. The objective of this study was to determine the correlation between the 21-gene RS and IHC-measured Ki67 with the prognostic classification groups recommended by the International Ki67 Working Group (IKWG). The authors performed a retrospective chart review of women who had hormone receptor (HR)-positive, human epidermal growth factor receptor 2-negative early breast cancer with zero to three positive lymph nodes and both Ki67 and the 21-gene RS performed at their institution from 2013 to 2021. Patients were categorized into low (≤5%), intermediate (6%-29%), and high Ki67 groups (≥30%) according to IKWG recommendations. Overall agreement and risk-stratified agreement between Ki67 and RS were assessed with the proportion of agreement and the κ statistic. The study included 525 patients with HR-positive breast cancer. Among the 49% of patients with intermediate Ki67 values of 6%-29%, the distribution of low (0-10), intermediate (11-25), and high RS (26-100) was 19%, 66%, and 15%, respectively. There was slight agreement (κ=0.01-0.20) between Ki67 and RS (κ=0.027) in the overall population, although this was not significant (p=.1985). There was fair agreement (κ=0.21-0.40) between high Ki67 and RS values (κ=0.280; p < .0001). A higher progesterone receptor percentage was associated with lower RS values (p > .0001) but not lower Ki67 values. A positive nodal status and a larger tumor size were associated with higher Ki67 values (p=.0059 and p < .0001) but not with RS. In this group of patients selected to have a 21-gene RS, there was no significant correlation between Ki67 and RS in the overall population, and there was fair agreement between high Ki67 and high RS values. In patients with early-stage, hormone receptor-positive breast cancer, decisions on adjuvant chemotherapy are based on certain biological features of the cancer and genomic assays such as the Oncotype DX Recurrence Score (RS). The goal of this study was to determine the correlation between Ki67, a marker of proliferation, and the Oncotype DX RS, a 21-gene assay demonstrated to be predictive of an adjuvant chemotherapy benefit in patients with early-stage breast cancer. In 525 patients, the authors did not find a significant correlation between Ki67 and RS.

Correlation of Ki67 working group prognostic risk categories with oncotype DX recurrence score (RS) in early breast cancer (EBC).

553 Background: The 21-gene RS (Oncotype DX) provides prognostic information for distant recurrence risk and is predictive of adjuvant chemotherapy benefit in hormone receptor (HR)-positive, HER-2 negative EBC. Ki67 protein expression is a proliferation marker that is determined by immunohistochemistry (IHC). The International Ki67 Working Group (IKWG) has provided guidelines for clinical use of Ki67 for prognostic classification (PMID: 33369635). The objectives of this study were to determine the correlation between IHC-measured Ki67 with the 21-gene RS, and evaluate their association with other anatomic and biologic tumor features. Methods: We performed a retrospective chart review of women with HR-positive, HER-2 negative EBC with 0-3 positive lymph nodes who had both Ki67 (via IHC using MIB-1 antibody on surgical specimen at our institutional pathology CLIA laboratory) and 21-gene RS between 2013 to 2021. Patients were categorized into Ki67 low (≤ 5%), intermediate (6-29%), and high (≥30%) based on IKWG recommendations. Overall and risk stratified agreement between Ki67 and RS were assessed using the proportion of agreement and Kappa statistic. Linear regression was used to test for associations between tumor features of ER%, PR%, and tumor size and log transformed Ki67 and RS. A t-test was used to compare average log transformed Ki67 and RS by tumor differentiation and nodal status. Results: We identified 461 patients with HR-positive BC of whom 26.7% were ≤ 50 years at diagnosis, 30% pre-menopausal and 10% node-positive. Overall, 29% (n = 137) of patients had low Ki67, 49% (n = 227) intermediate, and 21% (n = 97) high Ki67. 18% (n = 85) had RS 0-10, 67% (n = 311) had RS 11-25 and 14% (n = 65) had RS ≥ 26. There was no significant agreement (kappa &lt; 0) between Ki67 and RS (Kappa = -0.0035, p = 0.5406) in the overall population and fair agreement (kappa 0.21-0.40) between high Ki67 and RS (Kappa = 0.2510, p &lt; 0.0001). Higher ER% was significantly associated with lower RS (p &lt; 0.0001) and lower Ki67 (p = 0.0042). High tumor grade was associated with higher RS and higher Ki67 (p &lt; 0.0001). Higher PR% was associated with lower RS (p &gt; 0.0001) but not lower Ki67. Positive nodal status and larger tumor size were associated with higher Ki67 (p = 0.0081, p &lt; 0.0001) but not RS. Among the 49% of patients with intermediate Ki67 of 6-29%, the distribution of low, intermediate, and high RS was 24%, 65%, and 11%, respectively. Conclusions: In this group of patients selected to have a 21-gene RS, there was no correlation between Ki67 and RS in the overall population, and fair agreement between high Ki67 and high RS. Among the approximately one-half with an intermediate Ki67 of 6-29%, 89% would be spared chemotherapy based on a low-intermediate RS. In patients with high Ki67, 68% might be spared chemotherapy based on the RS. In the low Ki67 group, 6% had a high RS. Ki67 has limited utility in identifying patients with high or low RS.

The correlation analysis of 21-gene assay use in uninsured and underrepresented minorities with estrogen receptor (ER) positive HER2 negative breast cancer.

e12531 Background: 21-gene breast cancer recurrence-score assay (Oncotype DX) have been used to predict recurrence risks and guide adjuvant chemotherapy. However, access to such tests is limited, especially in a population concentrated with uninsured and underserved patient populations. Previously equations such as the Magee equation has been proposed to predict correlation of the recurrence score and the estimated recurrence score with high concordance rate. This study examines the concordance of such an assay to predicted scores in uninsured and underrepresented minority heavy public hospital. Methods: We performed a retrospective chart review of 68 women with hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer seen at University Hospital (public safety net hospital in Newark, New Jersey with greater majority of the patient population consists of underrepresented minorities such as Black/African Americans and Latino/Hispanics). 6 patients did not have pathology records, 9 patients did not have the Oncotype information available, and 4 patients were waiting on the results. Of the pre-menopausal eligible patients, two did not have any treatment or follow up information available and were included as part of the correlation assay, however, no. Results: Of the 47 eligible patients with follow-up information, 13 had a low recurrence score of up to 10 if post-menopausal and up to 15 if pre-menopausal, 22 had an intermediate recurrence score of 11 to 25 if post-menopausal and 16 to 25 if pre-menopausal, and 12 had a high recurrence score of greater than 26 according to the national comprehensive cancer network guidelines. The Pearson correlation between the Magee predicted score and Oncotype recurrence score was 0.73 (p &lt; 0.001). All patients received hormone therapy and 5 patients total had recurred. 2 were pre-menopausal and had received adjuvant chemotherapy. 3 were post-menopausal in low and intermediate categories who had not received adjuvant chemotherapy. Conclusions: This study shows a high correlation between the predicted Magee score and Oncotype recurrence score. This reflects a possible use in the prediction scoring system as another resource for prognostication and guidance in treatment especially in the underinsured population.

Abstract P2-11-13: Distinctive clinicopathological features of premenopausal women with intermediate 21-gene recurrence score

Abstract Backgroud Since the results of TAILORx trial were published, it was shown that premenopausal young patients with intermediate Oncotype Dx(ODx) recurrence score(RS) (16-25) may benefit from adjuvant chemotherapy. In secondary analysis of the TAILORx trial, clinicopathological features can provide complementary information in addition to Oncotype Dx results. Although ambiguous benefit of adjuvant chemotherapy in premenopausal women with intermediate risk makes clinical decision difficult, the baseline characteristic may vary depending on menopausal status. This study intends to analyze whether the intermediate-risk group shows differences in characteristics by menopausal status. Materials and Methods 760 early breast cancer patients with ER positive, HER2 negative and lymph node negative patients who have been tested ODx from July 2013 to December 2020 at Severance Hospital were retrospectively reviewed. Results Of the 760 patients, 262 patients were postmenopausal status and 498 patients were premenopausal status. Among 262 postmenopausal patients, 152 patients were in low-risk group(RS 0-20), 43 patients were in intermediate-risk group(RS 21-25), 67 patients were in high-risk group(RS 26-100). Among 498 patients, 353 patients were in low-risk group(RS 0-20), 75 patients were in intermediate-risk group(RS 21-25), 70 patients were in high-risk group(RS 26-100), respectively. In premenopausal patients with intermediate risk, clinical risk group, PR score, and Ki-67 showed a significant difference from the low risk group(p-value 0.003, &amp;lt;0.001 and 0.005, respectively), but no significant difference from the high risk group(p-value 0.242, 0.085 and 0.729, respectively). However, in postmenopausal patients with the intermediate risk, clinical risk group and Ki-67 did not show a significant difference from the low risk group(p-value 1.000 and 0.120, respectively), but showed a significant difference from the high risk group.(p-value 0.009 and 0.001, respectively). Conclusion In this study, some of clinicopathological characteristics of premenopausal patients with intermediate risk were closer to those of high risk group than in the low risk group, unlike postmenopausal patients with intermediate risk. In premenopausal patients with intermediate risk, benefits from adjuvant chemotherapy may be unclear, but when considering the baseline characteristic itself, there is a significant difference with the low risk group when compared with postmenopausal patients. In that point of view, more aggressive treatment decision like adjuvant chemotherapy would be helpful to premenopausal patients with intermediate risk. Keywords: 21-gene recurrence score, premenopausal breast cancer, clinicopathological features Citation Format: Jung Min Park, Jee Hyun Ahn, Soon Bo Choi, Jieon Ko, Jee Ye Kim, Hyung Seok Park, Seung Il Kim, Byeong-Woo Park, Seho Park. Distinctive clinicopathological features of premenopausal women with intermediate 21-gene recurrence score [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 P2-11-13.

Impact of TAILORx on chemotherapy prescribing and 21-gene recurrence score-guided treatment costs in a population-based cohort of patients with breast cancer.

The trial assigning individualized options for treatment (Rx) (TAILORx) confirmed the predictive value of the 21-gene recurrence score (RS) assay in hormone receptor (HR)-positive, HER2-negative, node-negative breast cancer and established thresholds for chemotherapy benefit in younger and older patients. Real-world chemotherapy use and RS-guided treatment costs in British Columbia post-TAILORx were examined. The authors assembled 3 cohorts of HR-positive, HER2-negative, node-negative patients with breast cancer defined by diagnosis: before RS funding (cohort 1 [C1]: January 2013-December 2013), after introduction of public RS funding (cohort 2 [C2]: July 2015-June 2016), and after TAILORx results (cohort 3 [C3]: July 2018-June 2019). Chemotherapy use was compared between cohorts by age and RS. Budgetary impacts of RS testing on chemotherapy costs were evaluated pre- and post-TAILORx. Among the 2066 patients included, chemotherapy use declined by 19% after RS funding was introduced and by an additional 23% after TAILORx publication (P = .001). Reduction in chemotherapy use was significant for RS 11-20 tumors (C3 vs C2, P = .004). There was no significant change in chemotherapy use in patients >50 years old (C2:12% vs C3:10%, P = .22). RS testing was associated with higher cost savings post-TAILORx, except in patients 70 to 80 years old, where testing led to excess costs when adjusting for the low rate of RS-concordant chemotherapy prescribed. TAILORx has had population-based impacts on chemotherapy prescribing in intermediate RS tumors and patients ≤50 years old. The lower clinical use of RS and increased spending in patients 70-80 years old highlights the importance of careful selection of older candidates for high-cost genomic testing. The 21-gene recurrence score (RS) test helps predict whether patients with hormone-positive, HER2-negative, lymph node-negative breast cancer are likely to benefit from chemotherapy. The recent trial assigning individualized options for treatment (Rx) (TAILORx) found that patients with intermediate RS tumors did not benefit from chemotherapy. The authors assessed whether TAILORx results translated to real-world changes in chemotherapy prescribing patterns. In this study, chemotherapy use decreased by 23% after TAILORx, with the greatest reductions seen among intermediate RS tumors and younger patients. In contrast, RS testing had lower clinical value and increased treatment costs in elderly patients, which requires further study to ensure optimal care for this age group.

Distribution, Chemotherapy Use, and Outcome of the 21-Gene Recurrence Score Between Chinese and White breast Cancer in the United States

To compare the distribution, chemotherapy-decision making, and prognosis of the 21-gene recurrence score (RS) between Chinese breast cancer (BC) in the United States and White American (WA) BC. We identified early-stage and estrogen receptor-positive BC patients diagnosed between 2004 and 2015. Multivariate logistic regression, Kaplan-Meier analysis, and multivariate Cox proportional hazards models were used for statistical analyses. A total of 67,486 patients were identified, including 66,215 (98.1%) WA patients and 1271 (1.9%) Chinese patients. Regarding the RS, 38,894 (57.6%) had low RS, 23,882 (35.4%) had intermediate RS, and 4710 (7.0%) had high RS. A similar distribution of RS was found between WA and Chinese BC (P=.280). The race was not the predictor associated with high RS. Similar trends of chemotherapy use were found in Chinese and WA BC. In WA BC, there were 4.1%, 31.5%, and 72.2% of patients receiving chemotherapy in low, intermediate, and high RS cohorts, respectively (P < .001). The proportion of chemotherapy use was 6.8%, 30.9%, and 74.0% in Chinese BC with low, intermediate, and high RS cohorts, respectively (P < 0.001). The multivariate prognostic analyses indicated that a higher RS was independently associated with an inferior breast cancer-specific survival. Similar trends were found among those with Chinese and WA BC. Our results demonstrate similar distribution, chemotherapy use, and outcome of the 21-gene RS between Chinese and WA BC in the United States.

407 Requesting, Treatment and Outcomes Following Oncotype DX Testing in Breast Cancer

Abstract Aim Oncotype DX (ODX) is a 21-gene assay for invasive breast cancer that yields a recurrence score (RS) value which indicates the risk of distant recurrence and the benefit from chemotherapy. NICE has laid down guidance regarding the criteria for test requesting which include having early breast cancer at an intermediate risk of distant recurrence that is ER-positive, HER2-negative and LN-negative. The aim of this study was to determine whether ODX was appropriately requested and followed. Treatment and outcomes were also observed. Method The study included all patients from The Countess of Chester Hospital who had undertaken ODX testing in the years 2015-2017. Patients were identified and clinicopathological data was obtained from clinic notes and pathology reports. NPI and PREDICT scores were calculated. The ODX original cut-off values were used. Results All 65 patients included in the study were ER-positive, 1 was HER2-positive and 1 was LN-positive. 9 patients had ODX requested inappropriately, all of which were low risk on both NPI and PREDICT. Chemotherapy was received by 1/32 low risk patients (RS 0-17), 6/24 intermediate risk patients (RS 18-30) and 5/5 high risk patients (RS 31-100). 57 patients had no recurrence, 2 patients had local recurrence (intermediate RS), 1 patient had distant recurrence (low RS) and 1 patient had metastasis (low RS). Chemotherapy was not received by any of the patients who experienced recurrence. Conclusions Adherence to NICE guidance regarding ODX requesting needs further emphasising. This would help reduce unnecessary patient investigation, costs, and pathology-lab workload.