Multigene assays in early breast cancer: Current evidence, limits and future directions.

Background and ObjectiveBreast cancer is a highly heterogeneous disease. Its incidence rate is increasing year by year and the mortality rate is the highest in female malignant tumors. Even patients with the same clinical stage and pathological grade have different response to treatment and postoperative recurrence risk. Although the prognosis of breast cancer in China has been gradually improved, there is still a certain gap compared with the 5-year survival rate as high as 89% in developed countries. In recent years, with the continuous enrichment of molecular sequencing data of breast cancer, gene detection technology has important reference value in prognosis judgement and guiding treatment of early breast cancer. This article reviews the current application and latest progress of genetic tests in comprehensive treatment for breast cancer, with a view to promote the precise treatment of breast cancer in clinical practice.MethodsWe conducted searches using the MeSH terms ‘breast neoplasms’ and ‘genetic testing’ in the PubMed databases from root to 22 January 2021. We conducted an additional search in the National Comprehensive Cancer Network (NCCN) and American Society of Clinical Oncology (ASCO) guidelines to obtain additional information. The search was limited to English, Dutch, French and German articles and research involving humans. Out of the references screened, 51 articles were found eligible for inclusion finally.Key Content and FindingsThe article reviews the mechanisms and clinical trials of five genetic tests including Oncotype Dx, Mammaprint, Endopredict, mRNA expression of 50 genes (PAM50) and breast cancer index (BCI) in comprehensive treatment for breast cancer. All these tools have been proved to have prognosis value, but only two of them, Oncotype Dx and Mammaprint, are recommended as predictive tools for chemotherapy by National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO).ConclusionsIn order to promote the comprehensive treatment of breast cancer to “precision” and “individualization” for further development, people have extensively researched on multigene testing technology represented by Oncotype Dx, Mammaprint, Endopredict and mRNA expression of 50 genes (PAM50) and breast cancer index (BCI). Each of these five tools has its advantages and limitation, which must be weighed in a wise application.

In December 2022, breast cancer specialists gathered at the annual San Antonio Breast Cancer Symposium to hear the latest news on breast cancer research and clinical care. Here are several key studies. The results of the Palbociclib After CDK and Endocrine Therapy (PACE) trial show no benefit from continuing the CDK4/6 inhibitor palbociclib in patients receiving endocrine therapy plus palbociclib for metastatic, estrogen receptor–positive (ER+)/human epidermal growth factor receptor 2–negative (HER2–) breast cancer.1 “Continuation of CDK4/6 inhibition beyond prior progression using palbociclib was not helpful versus fulvestrant” says Erica L. Mayer, MD, MPH, director of breast cancer clinical research at the Dana-Farber Cancer Institute and an associate professor of medicine at Harvard Medical School in Boston, Massachusetts, who presented the findings at the symposium. “If a patient progresses while on a CDK4/6 inhibitor, we would not recommend changing to palbociclib or continuing palbociclib as a treatment maneuver.” The PACE trial is a multicenter, phase 2, prospective trial designed to explore the question of whether patients with metastatic, ER+/HER2– breast cancer receiving endocrine therapy and a CDK4/6 inhibitor should continue a CDK4/6 inhibitor if their disease progresses. The study included 220 patients randomized to one of three treatment arms: standard treatment with endocrine therapy alone (fulvestrant), experimental therapy with fulvestrant plus CDK4/6 inhibition continuation with palbociclib, and an exploratory therapy with the triplet combination of fulvestrant, palbociclib, and avelumab (an immuno-oncology drug). The primary end point was the comparison of progressionfree survival (PFS) for patients treated with standard therapy and patients treated with experimental therapy. At a median of approximately 2 years, the study showed no improvement in median PFS for patients who continued CDK4/6 inhibition plus fulvestrant versus fulvestrant alone (4.6 months vs. 4.8 months), with a hazard ratio of 1.11 found for the experimental therapy (90% CI, 0.74–1.66; p = .62). On the basis of preclinical data suggesting a benefit in this setting of adding avelumab to fulvestrant and a CKD4/6 inhibitor, the study also assessed PFS with fulvestrant alone versus the triplet therapy. Although no significant differences were found between the two groups, patients treated with triplet therapy had a prolonged median PFS of 8.1 months. Dr Mayer calls the findings with the triplet therapy “intriguing” and says that she and her colleagues hope to study this regimen further. “Prior attempts to combine immunotherapy with endocrine therapy and CDK4/6 inhibition have been complicated by significant immune toxicities,” she adds, “but that was not seen with this triplet.” She also underscores that there are many other potential treatment options showing promise in the post-CDK4/6 inhibitor setting for ER+/HER2– disease, including oral selective estrogen receptor degraders, AKT/PIK3CA/mTOR inhibitors, and other CDK4/6 inhibitors such as ribociclib, on the basis of phase 2 data from the MAINTAIN trial.2 Follow-up results of the monarchE trial show that the addition of 2 years of abemaciclib to standard treatment (chemotherapy, radiotherapy, and endocrine therapy) significantly reduced the risk of recurrence in patients with high-risk, node-positive, hormone receptor–positive (HR+)/HER2– early breast cancer at high risk of disease recurrence. “We now have 42 months of median follow-up, and the key message from the new 4-year efficacy data is that the absolute benefit [of adding abemaciclib] is increasing year on year, indicating a clear role for abemaciclib in preventing recurrence of breast cancer,” says Stephen Johnston, MA, PhD, professor of breast cancer medicine and head of medical oncology at the Royal Marsden NHS Foundation Trust and the Institute of Cancer Research in London, who presented the updated findings and is lead author of the study simultaneously published in Lancet Oncology.3, 4 The phase 3 monarchE trial is an open-label, randomized trial assessing the efficacy and safety of the addition of the CDK4/6 inhibitor abemaciclib to endocrine therapy for adult patients with HR+/HER2–, node-positive early breast cancer at high risk of recurrence. The trial includes 5637 patients randomly assigned to endocrine therapy alone (n = 2829) or abemaciclib plus endocrine therapy (n = 2808). At a median follow-up of 42 months, the study showed that the addition of abemaciclib to endocrine therapy improved invasive disease-free survival (85.8% vs. 79.4%; absolute difference, 6.4%) and distant relapse-free survival (88.4% vs. 82.5%; absolute difference, 5.9%) in comparison with endocrine therapy alone. The updated results showed that the invasive disease-free survival benefit previously reported was sustained (hazard ratio, 0.664; 95% CI, 0.578–0.762; p < .0001).5 “For these high-risk patients who may relapse early on endocrine therapy despite standard of care, we now have an additional effective therapy to reduce risk of recurrence,” says Dr Johnston, adding that patients eligible for this treatment are easy to identify on the basis of the clinicopathological features of nodal burden, tumor size, and tumor grade. The Breast Cancer Index (BCI) is prognostic for premenopausal women with HR+, early-stage breast cancer according to the results of a study presented by Ruth O’Regan, MD, chair of the Department of Medicine at the University of Rochester in New York.6 The BCI genomic test can predict which patients are most likely to benefit beyond 5 years of extended endocrine therapy in early-stage, HR+ breast cancer with node-negative (N0) or node- positive disease with up to 3 positive nodes (N1). BCI uses clinical information from an individual patient to compare to data from five studies and more than 4500 pre- and post menopausal women with various treatment histories and clinical features.7 No genomic assay currently exists for predicting which patients in this setting will benefit from ovarian suppression, however. If validated in another series, the BCI could be the first assay to do so. To assess BCI’s effectiveness in predicting which patients would benefit from ovarian suppression, Dr O’Regan and her colleagues performed the BCI on breast cancers from patients enrolled in the Suppression of Ovarian Function Trial (SOFT). The trial, which randomly assigned premenopausal patients with HR+, invasive early breast cancer to ovarian function suppression (OFS) plus tamoxifen, OFS plus exemestane, or tamoxifen alone after surgery, showed improved outcomes when OFS was added to endocrine therapy (tamoxifen or exemestane).8 In the current study, 1687 breast tumors from patients enrolled in the SOFT trial were analyzed: 58% had a low BCI, and 42% had a high BCI. Results showed that patients with tumors that had a low BCI score had a lower risk of distant recurrence at 12 years, whereas those with a high BCI score had an increased risk. Further results showed that the addition of OFS to endocrine therapy for tumors with a low BCI score reduced the recurrence risk at 12 years, regardless of age, lymph node involvement, or chemotherapy, in comparison with endocrine therapy alone. No significant differences were found for tumors with high BCI scores. “The Breast Cancer Index is prognostic for patients with early-stage, hormone receptor-positive cancer who have received endocrine therapy with or without chemotherapy,” says Dr O’Regan, who adds that a validation study is currently planned.

Background Residual risk of relapse remains a substantial concern for breast cancer patients as greater than half of recurrences occur beyond the initial 5y of tamoxifen therapy. First generation multigene signatures provide further prognostic information to standard clinical and pathological factors, however, their utility is strongest for predicting early relapse (≤5y post-diagnosis), and they have limited prognostic value for late metastatic risk. Breast Cancer Index (BCI), a continuous risk index based on the combination of HOXB13:IL17BR (H:I) and the molecular grade index (MGI), estimates the individual risk of recurrence in ER+, LN- breast cancer patients. In this study, the prognostic performance of BCI for predicting early versus late relapse (≤5y vs &amp;gt;5y post-diagnosis) was examined. Methods: Gene expression profiling was performed on RNA extracted from FFPE tumor samples from untreated, postmenopausal, ER+ early stage breast cancer patients in the randomized Stockholm Trial. RT-PCR assay, pre-defined BCI score, H:I and MGI cut-points, and risk group categorization were done as previously described (Jerevall et al., Br J Cancer 2011). Association of gene expression data with the clinical endpoint of time to distant metastasis was assessed by Kaplan-Meier analysis using the log rank test; time-varying coefficient Cox proportional models were used to estimate the time-dependent hazard ratios (HRs). Results: Analyses included 274 ER+, LN- patients (51% PR+, 87% HER2−, 63% grade 2, 17.7 y median follow-up) who did not receive adjuvant tamoxifen treatment. BCI was significantly associated with 10-year distant metastasis-free survival, with probabilities of 91% (86-96%), 82% (74-91%), and 65% (52-80%) for the low, intermediate, and high-risk BCI groups, respectively (HR high versus low-risk group = 4.31; 95%CI, 2.23−8.33; P=0.00001). Risk stratification for the first 5-y post-diagnosis using time-varying coefficient Cox models showed both MGI and BCI were significantly prognostic with HRs of 6.13 (95% CI: 2.11−17.8; P=0.0009) and 5.77 (95% CI: 2.16−15.39; P=0.0005). For prediction of late relapse in the subset of patients that remained distant metastasis-free for at least 5-y (N=221), MGI decreased in prognostic utility (HR 1.65, 0.76−3.56; P=0.2), consistent with other proliferation-based gene signatures. In comparison, both H:I and BCI were significantly associated with risk of late relapse [HRs 2.89 (1.31−6.36; P=0.009); 3.31(1.3−8.39); P=0.012]. Conclusions: This post-hoc analysis of a randomized clinical trial cohort demonstrates the prognostic utility of BCI to predict disease outcome for both early and late risk of relapse in untreated patients with early stage breast cancer. Given the significant need for predictors of late risk, the stability of BCI prognostic performance may have important implications for the type and duration of treatment for hormone-responsive breast cancer. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-12-12.

INTRODUCTION: Oncotype DX® recurrence score (ODX RS) is a 21-gene assay warranted to determine the the prognosis in patients with hormone receptor positive, HER-2 negative early stage breast cancer. In this context, the test is also predictive of benefit of adjuvant chemotherapy.1,2,3 OBJECTIVES: We aimed to correlate the clinical and pathological factors associated with Oncotype DX® 21-Gene in patients diagnosed with early stage Breast Cancer. Additionally, description of adjuvant treatment patterns and survival outcomes were described according to the Oncotype DX® 21-Gene result. METHODS: Data from medical records from a single center in Brazil were collected retrospectively from women over 18 years diagnosed with early breast cancer between 2012 and 2022. Included patients were diagnosed with stage T1-T2 breast cancer, hormone receptor positive, HER-2 negative, with up to three positive lymph nodes. All included patients had an Oncotype DX® test performed after definitive breast surgery. The ODX RS has been categorized into two levels according to menopausal status. Correlation between breast cancer recurrence and clinicopathological characteristics was done. The software SPSS was used for statistical analyzes with the significance of 0.05. RESULTS: From 197 patients, 20 have had breast cancer recurrence (10.15%) whom 10 were premenopausal and 10 were postmenopausal. The median ODX RS in these 20 patients was 15 (ranged from 9 to 31). The most common site of recurrence was breast and regional recurrence in 18 patients (90%). Adjuvant chemotherapy was omitted in 16 patients (80%) who have had breast cancer recurrence. Among premenopausal patients whose ODX RS was &amp;gt;20, 33 patients (91.66%) received adjuvant chemotherapy. Among postmenopausal patients whose ODX RS was &amp;gt;25, 19 (86.36%) received adjuvant chemotherapy. The probability of recurrence free survival was worse in premenopausal patients &amp;gt; 44-years-old compared to those with &amp;lt; =44 years-old (p = 0.036) and also worse in histological grade 3 tumors compared to grade 1 (p=0.0048). Tumor size &amp;gt;14 millimeters (mm) was correlated to worse recurrence free survival in premenopausal patients (p=0.017). Low estrogen and progesterone receptor was associated with a higher ODX RS (p=0.0035 and p&amp;lt; 0.0001, respectively) in premenopausal patients, but not associated with recurrence free survival. Clinicopathological characteristics and recurrence free survival correlation in postmenopausal patients were not significant. CONCLUSION: This retrospective analysis suggests that factors other than the Oncotype DX® score, such as age and grade contributed to worse survival outcomes among our patients population. Of note, age older than 44 years-old, histological grade 3 and tumor size &amp;gt;14 mm were associated with a higher probability of recurrence in premenopausal patients, despite the Oncotype DX® score. REFERENCES: 1. Paik S, Shak S, Tang G, Kim C, Baker J, Cronin M, et al. A multigene assay to predict recurrence of tamoxifen-treated, node-negative breast cancer. N Engl J Med [Internet]. 2004;351(27):2817–26. Available from: http://dx.doi.org/10.1056/NEJMoa041588. 2. Sparano JA, Gray RJ, Makower DF, Pritchard KI, Albain KS, Hayes DF, et al. Adjuvant chemotherapy guided by a 21-gene expression assay in breast cancer. N Engl J Med [Internet]. 2018;379(2):111–21. Available from: http://dx.doi.org/10.1056/NEJMoa1804710. 3. Kalinsky K, Barlow WE, Gralow JR, Meric-Bernstam F, Albain KS, Hayes DF, et al. 21-gene assay to inform chemotherapy benefit in node-positive breast cancer. N Engl J Med [Internet]. 2021;385(25):2336–47. Available from: http://dx.doi.org/10.1056/NEJMoa2108873. Table 1 – Clinical and pathological characteristics of 197 hormone receptor positive, HER-2 negative early breast cancer patients who did the Oncotype DX® 21-Gene Recurrence Score assay. Data from medical records collected retrospectively of women diagnosed with early breast cancer between 2012 and 2022 from a single center in Brazil. Figure 1 – Probability of recurrence free survival in premenopausal patients according to age &amp;lt;=44 (blue line) or &amp;gt; 44-years-old (pink line). Data from medical records collected retrospectively of women with hormone receptor positive, HER-2 negative early breast cancer who did the Oncotype DX® 21-gene assay diagnosed between 2012 and 2022 from a single center in Brazil. Figure 2 – Probability of recurrence free survival in premenopausal patients according to histological grade. Tumor with histological grade 1 (blue line) or histological grade 3 (pink line). Data from medical records collected retrospectively of women with hormone receptor positive, HER-2 negative early breast cancer who did the Oncotype DX® 21-gene assay diagnosed between 2012 and 2022 from a single center in Brazil. Citation Format: Carolina Cavalcanti Gonçalves Ferreira, Julio Araujo, Shermann Brandão Rodrigues Moreira, Antônio Buzaid, Débora Gagliato. Clinical and pathological factors associated with Oncotype DX® 21-Gene recurrence score in patients diagnosed with early stage breast cancer in a low-middle income country [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 PO2-02-03.

The role of radiation therapy in the management of primary breast cancer

Gene expression profiling (GEP) and expanded immunohistochemistry (IHC) tests aim to improve decision-making relating to adjuvant chemotherapy for women with early breast cancer. The aim of this report is to assess the clinical effectiveness and cost-effectiveness of nine GEP and expanded IHC tests compared with current prognostic tools in guiding the use of adjuvant chemotherapy in patients with early breast cancer in England and Wales. The nine tests are BluePrint, Breast Cancer Index (BCI), IHC4, MammaPrint, Mammostrat, NPI plus (NPI+), OncotypeDX, PAM50 and Randox Breast Cancer Array. Databases searched included MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE and The Cochrane Library. Databases were searched from January 2009 to May 2011 for the OncotypeDX and MammaPrint tests and from January 2002 to May 2011 for the other tests. A systematic review of the evidence on clinical effectiveness (analytical validity, clinical validity and clinical utility) and cost-effectiveness was conducted. An economic model was developed to evaluate the cost-effectiveness of adjuvant chemotherapy treatment guided by four of the nine test (OncotypeDX, IHC4, MammaPrint and Mammostrat) compared with current clinical practice in England and Wales, using clinicopathological parameters, in women with oestrogen receptor-positive (ER+), lymph node-negative (LN-), human epidermal growth factor receptor type 2-negative (HER2-) early breast cancer. The literature searches for clinical effectiveness identified 5993 citations, of which 32 full-text papers or abstracts (30 studies) satisfied the criteria for the effectiveness review. A narrative synthesis was performed. Evidence for OncotypeDX supported the prognostic capability of the test. There was some evidence on the impact of the test on decision-making and to support the case that OncotypeDX predicts chemotherapy benefit; however, few studies were UK based and limitations in relation to study design were identified. Evidence for MammaPrint demonstrated that the test score was a strong independent prognostic factor, but the evidence is non-UK based and is based on small sample sizes. Evidence on the Mammostrat test showed that the test was an independent prognostic tool for women with ER+, tamoxifen-treated breast cancer. The three studies appeared to be of reasonable quality and provided data from a UK setting (one study). One large study reported on clinical validity of the IHC4 test, with IHC4 score a highly significant predictor of distant recurrence. This study included data from a UK setting and appeared to be of reasonable quality. Evidence for the remaining five tests (PAM50, NPI+, BCI, BluePrint and Randox) was limited. The economic analysis suggests that treatment guided using IHC4 has the greatest potential to be cost-effective at a £20,000 threshold, given the low cost of the test; however, further research is needed on the analytical validity and clinical utility of IHC4, and the exact cost of the test needs to be confirmed. Current limitations in the evidence base produce significant uncertainty in the results. OncotypeDX has a more robust evidence base, but further evidence on its impact on decision-making in the UK and the predictive ability of the test in an ER+, LN-, HER- population receiving current drug regimens is needed. For MammaPrint and Mammostrat there were significant gaps in the available evidence and the estimates of cost-effectiveness produced were not considered to be robust by the External Assessment Group. Methodological weaknesses in the clinical evidence base relate to heterogeneity of patient cohorts and issues arising from the retrospective nature of the evidence. Further evidence is required on the clinical utility of all of the tests and on UK-based populations. A key area of uncertainty relates to whether the tests provide prognostic or predictive ability. The clinical evidence base for OncotypeDX is considered to be the most robust. The economic analysis suggested that treatment guided using IHC4 has the most potential to be cost-effective at a threshold of £20,000; however, the evidence base to support IHC4 needs significant further research. PROSPERO 2011:CRD42011001361, available from www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42011001361.

Background: For patients with early stage, hormone receptor positive (HR+) breast cancer, extension of endocrine therapy beyond 5 years reduces the ongoing risk of late distant recurrence and new primary breast cancer but is associated with potentially serious toxicities and side effects that can impair quality of life. While risk stratification by clinicopathological factors and prognostic biomarkers is recommended to guide patient selection, predictive biomarkers that are directly informative of therapeutic response are critical for clinical utility. Breast Cancer Index (BCI) is a gene expression-based signature that reports: 1) BCI Prognostic (BCI Score), which combines the Molecular Grade Index (MGI) with the HOXB13/IL17BR (H/I) ratio to provide individualized risk of late (post-5y) distant recurrence, and 2) BCI Predictive (BCI H/I), which predicts benefit from extended endocrine therapy. In this study, BCI and endocrine benefit from 5 vs 2.5y of extended letrozole were examined by comparing the deterministic effects of prognostic risk vs endocrine response in patients treated in the IDEAL trial.Methods: 908 patients with available tumor tissue were included in this pre-specified and blinded analysis, with recurrence-free interval (RFI) as the primary endpoint. Kaplan-Meier and Cox proportional hazards regression were performed using pre-defined assay cut-points. Clinically high prognostic risk was defined as pN+ and ≥pT2; low prognostic risk was defined as pN0 or pN1 and pT1 or G1. Genomic risk was defined by BCI prognostic categories (High vs Low risk). Results: Patients classified with endocrine responsive disease by BCI (H/I)-High status showed a statistically significant benefit from 5 vs 2.5y of letrozole irrespective of clinical risk, whereas those classified as BCI (H/I)-Low did not show benefit in either clinical risk category. Both clinically High and Low risk patients derived a similar magnitude of benefit when stratified as BCI (H/I)-High (12.5% and 15.1%, respectively). Evaluation of BCI (H/I) predictive performance in the context of BCI prognostic risk categories showed similar results. In particular, patients with High Risk/High Likelihood to benefit showed significantly improved outcomes with extended therapy (HR 0.42 [0.20-0.89]; absolute benefit 10.7%; P=0.020), whereas those with High Risk but Low Likelihood to benefit did not show response to extended endocrine therapy (HR 1.05 [0.58-1.88]; absolute benefit -0.7%; P=0.880), despite considerable risk of late distant recurrence (~20%). Conclusion: Results from this study highlight distinct tumor biology underlying recurrence risk vs endocrine responsiveness in HR+ early stage breast cancer. BCI (H/I) as a molecular signature to identify patients with endocrine responsive disease is a key determinant of benefit and improved outcome with extended endocrine therapy. Prediction of endocrine benefit with BCI (H/I) is a more actionable approach vs risk assessment to individualize discontinuation of or continued treatment with prolonged durations of endocrine therapy. Prognostic RiskBCI Predictive NHR (95% CI)P valueClinical RiskHigh Risk: N+/ T2+ (N=353)High BCI(H/I)1620.32 (0.10-0.98)0.035Low BCI(H/I)1911.13 (0.55-2.31)0.742Low Risk: N0 or N1 &amp; T1 or grade 1 (N=404)High BCI(H/I)1910.15 (0.03-0.66)0.004Low BCI(H/I)2130.75 (0.33-1.70)0.484Genomic RiskHigh BCI Score(N=621)High BCI(H/I)3410.42 (0.20-0.89)0.020Low BCI(H/I)2801.05 (0.58-1.88)0.880Low BCI Score(N=227)High BCI(H/I)600.35 (0.04-3.38)0.344Low BCI(H/I)1670.64 (0.22-1.92)0.425 Citation Format: Gerrit-Jan Liefers, Iris Noordhoek, Kai Treuner, Hein Putter, Yi Zhang, Jenna Wong, Elma Meershoek-Klein Kranenbarg, Marjolijn Duijm-de Carpentier, Cornelis JH Van De Velde, Catherine A Schnabel. Breast cancer index is a molecular signature of endocrine responsiveness that determines extended endocrine benefit independent of prognostic risk [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD2-11.

Objective: The purpose of this guideline is to determine the clinical utility of multigene profiling assays in individuals with early-stage invasive breast cancer. Methods: This guideline was developed by Ontario Health (Cancer Care Ontario)’s Program in Evidence-Based Care (PEBC) through a systematic review of relevant literature, patient- and caregiver-specific consultation and internal and external reviews. Recommendation 1: In patients with early-stage estrogen receptor (ER)-positive/human epidermal growth factor 2 (HER2)-negative breast cancer, clinicians should consider using multigene profiling assays (i.e., Oncotype DX, MammaPrint, Prosigna, EndoPredict, and the Breast Cancer Index) to help guide the use of systemic therapy. Recommendation 2: In patients with early-stage node-negative ER-positive/HER2-negative disease, clinicians may use a low-risk result from Oncotype DX, MammaPrint, Prosigna, EndoPredict/EPclin, or Breast Cancer Index assays to support a decision not to use adjuvant chemotherapy. Recommendation 3: In patients with node-negative ER-positive/HER2-negative disease, clinicians may use a high-risk result from Oncotype DX to support a decision to offer chemotherapy. A high Oncotype DX recurrence score is capable of predicting adjuvant chemotherapy benefit. Recommendation 4: In postmenopausal patients with ER-positive/HER2-negative tumours and one to three nodes involved (N1a disease), clinicians may withhold chemotherapy based on a low-risk Oncotype DX or MammaPrint score if the decision is supported by other clinical, pathological, or patient-related factors. Recommendation 5: The evidence to support the use of molecular profiling to select the duration of endocrine therapy is evolving. In patients with ER-positive disease, clinicians may consider using a Breast Cancer Index (H/I) high assay result to support a decision to extend adjuvant endocrine therapy if the decision is supported by other clinical, pathological, or patient-related factors.

Studies of adrenal function were performed on 54 asthmatic patients who were taking long term high doses of inhaled beclomethasone dipropionate ranging from 500 to 2000 micrograms/day for between six and 60 months. Of the 43 patients taking up to 1500 micrograms/day, 39 (91%) had normal basal plasma cortisol concentrations and normal short tetracosactrin responses and 24 hour urinary free cortisol excretion was within the normal range in eight of nine patients tested. Some evidence of adrenal suppression was found in patients taking 2000 micrograms/day, with basal plasma cortisol below the normal range in four out of 11 patients and 24 hour urinary free cortisol excretion below the normal range in five out of six patients tested. Only one of the 11 patients taking 2000 micrograms/day had a short tetracosactrin response below the normal range: the mean rise in plasma cortisol was, however, significantly lower in this group than in those taking 1000 micrograms/day (328 (SE 30) and 506 (34) nmol/l respectively) (p less than 0.01). Patients taking more than 1500 micrograms/day of inhaled beclomethasone may require systemic corticosteroids during prolonged stress.

Adjuvant ovarian function suppression (OFS) with oral endocrine therapy improves outcomes for premenopausal patients with hormone receptor-positive (HR+) breast cancer but adds adverse effects. A genomic biomarker for selecting patients most likely to benefit from OFS-based treatment is lacking. To assess the predictive and prognostic performance of the Breast Cancer Index (BCI) for OFS benefit in premenopausal women with HR+ breast cancer. This prospective-retrospective translational study used all available tumor tissue samples from female patients from the Suppression of Ovarian Function Trial (SOFT). These individuals were randomized to receive 5 years of adjuvant tamoxifen alone, tamoxifen plus OFS, or exemestane plus OFS. BCI testing was performed blinded to clinical data and outcome. The a priori hypothesis was that BCI HOXB13/IL17BR ratio (BCI[H/I])-high tumors would benefit more from OFS and high BCI portended poorer prognosis in this population. Settings spanned multiple centers internationally. Participants included premenopausal female patients with HR+ early breast cancer with specimens in the International Breast Cancer Study Group tumor repository available for RNA extraction. Data were collected from December 2003 to April 2021 and were analyzed from May 2022 to October 2022. Primary end points were breast cancer-free interval (BCFI) for the predictive analysis and distant recurrence-free interval (DRFI) for the prognostic analyses. Tumor specimens were available for 1718 of the 3047 female patients in the SOFT intention-to-treat population. The 1687 patients (98.2%) who had specimens that yielded sufficient RNA for BCI testing represented the parent trial population. The median (IQR) follow-up time was 12 (10.5-13.4) years, and 512 patients (30.3%) were younger than 40 years. Tumors were BCI(H/I)-low for 972 patients (57.6%) and BCI(H/I)-high for 715 patients (42.4%). Patients with tumors classified as BCI(H/I)-low exhibited a 12-year absolute benefit in BCFI of 11.6% from exemestane plus OFS (hazard ratio [HR], 0.48 [95% CI, 0.33-0.71]) and an absolute benefit of 7.3% from tamoxifen plus OFS (HR, 0.69 [95% CI, 0.48-0.97]) relative to tamoxifen alone. In contrast, patients with BCI(H/I)-high tumors did not benefit from either exemestane plus OFS (absolute benefit, -0.4%; HR, 1.03 [95% CI, 0.70-1.53]; P for interaction = .006) or tamoxifen plus OFS (absolute benefit, -1.2%; HR, 1.05 [95% CI, 0.72-1.54]; P for interaction = .11) compared with tamoxifen alone. BCI continuous index was significantly prognostic in the N0 subgroup for DRFI (n = 1110; P = .004), with 12-year DRFI of 95.9%, 90.8%, and 86.3% in BCI low-risk, intermediate-risk, and high-risk N0 cancers, respectively. In this prospective-retrospective translational study of patients enrolled in SOFT, BCI was confirmed as prognostic in premenopausal women with HR+ breast cancer. The benefit from OFS-containing adjuvant endocrine therapy was greater for patients with BCI(H/I)-low tumors than BCI(H/I)-high tumors. BCI(H/I)-low status may identify premenopausal patients who are likely to benefit from this more intensive endocrine therapy.

Background: The Breast Cancer Index (BCI) is a gene expression-based signature that stratifies patients based on the risk of overall (0-10 years) and late (post-5 years) distant recurrence (DR). BCI also predicts the likelihood of benefit from extended endocrine therapy in early-stage, HR+ breast cancer (BC). This study aims to explore the correlation between BCI and disease-free interval and possible associations between gene-expression-based classification by BCI and the genomic features of primary breast cancers in patients with HR+/HER2- breast cancer who developed metastatic relapse. Methods: Primary tumor samples from HR+/HER2- metastatic/recurrent BC patients underwent both BCI and MSK-IMPACT targeted sequencing. MSK-IMPACT identifies somatic mutations, rearrangements, and copy-number alterations in up to 505 cancer genes. Time to DR (TTDR) defined as the time between date of surgery and distant recurrence. Kaplan-Meier survival analysis and Cox proportional hazards regression were used to evaluate BCI's prognostic performance. Pearson’s correlation (R) was used for correlation between BCI score and TTDR. Fisher’s exact tests were used to identify genomic alterations with significant differences comparing BCI prognostic groups. Due to small sample size, comparisons were not adjusted for multiple testing. Results: The study includes 107 HR+/HER2- metastatic patients with primary tumors tested with both MSK-IMPACT and BCI: 44% post-menopausal, 60% T2/3, 64% grade 3, 56% lymph node positive (LN+). Consistent with the nature of this cohort (all experienced DR), BCI classified the majority of the patients (n=94, 88%) as high-risk for DR. The BCI score was negatively correlated with TTDR (R=-0.24, p=0.011). Patients classified as high-risk by BCI tended to have DR earlier than low-risk patients (median TTDR: 2.8y vs. 3.4y; HR=1.95 with 95% CI: 1.05-3.62; p=0.031). Overall, the genomic profile of the cohort was consistent with high-risk luminal primary tumors, with higher than expected rate of TP53 mutations (35%). Analysis of somatic genomic alterations by MSK-IMPACT revealed a trend that there are more mutations in PIK3CA and TBX3 in the BCI low-risk group compared to the high-risk group (77% vs 46%, p=0.038) and (38 vs 3%, p=0.020), respectively. Conclusion: In this cohort of high-risk BC patients who all had a DR event, BCI remained prognostic with lower BCI scores associated with longer TTDR. Initial findings from the genomic correlative analysis suggested an association of BCI with certain genomic features. Further analyses with additional samples are ongoing to substantiate these findings. Citation Format: Hong Zhang, Li Ma, Anton Safonov, Natalia Siuliukina, Julia Ah-Reum An, Subhiksha Nandakumar, Enrico Moiso, Edaise da Silva, Mehnaj Ahmed, Lisa Loudon, Konner Nelson, Kevin Murphy, Jade Oghoanina, Mark Robson, Sarat Chandarlapaty, George Plitas, Yi Zhang, Kai Treuner, Pedram Razavi. Associations between Breast Cancer Index Classifications and MSK-IMPACT Genomic Profiles in HR+/HER2- Breast Cancer [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P1-11-07.

187P - Summary of head-to-head comparisons of patient (pt) risk classifications by the 21-gene recurrence score (RS) assay and other genomic assays for early breast cancer (EBC)

MD, FRCS, FRCRMeyerstein Institute of Oncology and Academic Department of Surgery, University College London Hospitals NHS Trust,London, UKIn Time magazine’s extensively researched breast cancerissue (June 10, 2002), one particular quote had a specialresonance for us. In the introduction to a remarkablycomprehensive article, Dr Julie Gralow, an Oncologist atthe Fred Hutchinson Cancer Research Centre in Seattle,stated ‘‘We may be far overtreating our patients… We’venow got women being diagnosed with tumours that wouldprobably never have been treated if we didn’t havemammography. They probably would have lived long,natural, healthy lives never knowing they had breastcancer’’ (J Gralow, quoted in [1]).For some years it has been apparent that, for manypatients, powerful treatment by surgery (even when limitedto tumour excision with breast preservation) together witha 6 week programme of radiation therapy may be morethan sufficient. We already know a good deal (althoughnot of course enough) about the profile of a typical breastcancer patient with low risk of local and distant recur-rence: a small, low or moderate grade tumour, surgicallycompletely excised, positive for oestrogen and/or proges-terone receptors, negative for HER2 and with negativeaxillary nodes. Post-menopausal patients clearly have alower incidence of local recurrence; for example, in thelarge study by Bartelink et al [2], patients over the age of60 years had a rate of local recurrence following 50 Gywhole breast radiation of only 4% (without an additionalboost), the rate reducing still further to 2.5% with anadditional 16 Gy given by electron beam therapy. Forpatients aged 41 to 50 years, the rates were 9.5% and 5.8%,respectively (median follow-up 5.1 years). What’s more, anever increasing number of patients now present with smalltumours (,1 cm) identified on mammographic screening,of whom approximately three-quarters will have oestrogenreceptor (ER)/progesterone receptor (PR) positive tumours,for which targeted hormone therapy with tamoxifen offerssustained long-term benefit for both local and distantrelapse [3, 4]. Using a well tolerated oral aromataseinhibitor such as Anastrazole reduces the risk still further(for both local and distant relapse), also, incidentally,reducing by three-quarters the risk of development of acontralateral primary breast cancer [5].For all these reasons, we strongly support Gralow’sview. Even in younger women known to be at higher riskof relapse, including those with axillary node-positivedisease, the use of systemic adjuvant cytotoxics sharplyreduces the risk of recurrence [3, 4, 6]. For hormonereceptor-positive patients, i.e. the large majority, adjuvanthormone therapy as well as surgical or medical oophor-ectomy all add further benefit [2–4, 6].What is the consequence of Gralow’s observation? Inthe past, it has been regarded as mere flight of fancy toimagine that we can identify patients at such low risk ofrecurrence that a less intensive form of treatment thanlocal surgical excision followed by whole breast irradiationcould be regarded as ‘‘adequate’’. In this sense, thisgeneral policy remains little different in principle from theequally compelling (in its day) policy of radical, then lessdamaging forms of mastectomy – although admittedly,using local excision, breast preservation and post-operativeradiotherapy is generally regarded as more ‘‘humane’’ eventhough attempts at demonstrating an improved quality oflife have been largely elusive [7]. None the less, theevolving history of local treatment for early breast cancerhas centred on an ever increasing recognition of theimportance of breast conservation for body image andcosmesis, an essential requirement for most women. Thishas largely been achieved by the increasing acceptance ofbreast-conserving surgery with post-operative radiotherapy[8]. Yet despite this ready acceptance, recent data from theworld’s largest ever randomized breast cancer study, withexcellent quality control and a high level of expertise,confirm a mastectomy rate approaching 50% [ATACTrialists Group, unpublished data].We believe that the time has come to move on further.For many patients, particularly those presenting over theage of 50 years with small, low grade, ER positive, axillarynode negative tumours, it is surely right to question thenecessity of a lengthy and sometimes damaging course ofradiation therapy. Radiation oncologists who are totallysatisfied with their often excellent cosmetic results and lowrelapse rates following standard treatment should bearin mind the work of the Oxford-based Early BreastCancer Trialists’ Collaborative Group, namely that despitea lower breast cancer cause-specific death rate in irradiatedpatients, the increased mortality for other non-cancercauses wipes out this advantage [9]. The assumption thatthe excess non-cancer-related deaths in this large meta-analysis were due essentially to reliance on older outmodedradiation techniques may be correct – but it remains anassumption only, and considerable additional data attestto the cardiac, pulmonary and neurological dangers ofwhole breast irradiation [10–12]. Moreover, the use ofanthracycline-based chemotherapy regimens apparentlyincreases some of these risks still further [13].

Background: Patients with estrogen receptor positive (ER+) early breast cancer have a continuous yearly recurrence rate extending out to 15 years after having received adjuvant endocrine therapy for five years. More than half of the recurrences (i.e. late recurrences) in this group will occur beyond five years from diagnosis. Thus, residual risk of recurrence remains a substantial concern for ER+ breast cancer patients. Current multi-gene signatures have significant prognostic performance in predicting early recurrence (0–5 years post-diagnosis), however, such signatures have limited performance in predicting the risk of late recurrence (&amp;gt; 5 years) (Albain et al. Lancet Oncol 2010; 11: 55–65; Buyse et al. JNCI 2006; 98: 1183–1192). The comparative prognostic performance of Breast Cancer Index (BCI), Recurrence Score (RS) and IHC4 for predicting early and late recurrence was examined in the translational arm of Arimidex, Tamoxifen, Alone or in Combination trial (TransATAC). Methods: RNA extracted from 1102 formalin-fixed paraffin-embedded blocks of primary tumor samples previously collected for the TransATAC study was used to perform real-time RT-PCR for BCI analyses. BCI was calculated and risk groups were determined using pre-specified cut points. RS and IHC4 values were previously generated. The prognostic value of each signature beyond standard clinical variables (Clinical Treatment Score (CTS) was assessed using likelihood ratio chi-square (LR-χ2) and calculated by Cox proportional hazards models. Prognostic evaluation for early recurrences (0–5 years) was performed by censoring survival time to 5 years, and for late recurrences (5–10 years) by analyzing those patients who had remained recurrence-free for at least 5 years. Clinical endpoints examined were distant recurrence, any recurrence, breast cancer death and overall survival. Results: Of 1102 tumor specimens assayed, 29 failed quality control and 915 samples were matched for reportable values of BCI, IHC4 and RS. Here, only node-negative patients were evaluated (N = 665). All 3 signatures had significant prognostic performance for early distant recurrence (0–5 years), and overall (0–10 years) each provided prognostic information beyond CTS with LR-χ2 values of 22.7, 22.9 and 13.8 for BCI, IHC4 and RS, respectively. Notably, only BCI was significant beyond CTS for late distant recurrence (5–10 years) (LR-χ2: 7.97, p = 0.005) versus RS (LR-χ2: 0.51, p = 0.5) and IHC4 (LR-χ2: 1.63, p = 0.2). Similar comparative results of BCI, RS and IHC4 for late recurrence were observed for the other clinical endpoints. Discussion: This is the first large-scale clinical study to compare several multi-gene signatures for their prognostic strength to quantify late residual risk of recurrence after endocrine therapy. BCI, unlike IHC4 and RS, is a significant prognostic factor for late recurrence and enables the assessment of individual recurrence risk for ER+ patients recurrence-free after 5 years of endocrine therapy. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr S1-9.

Background: Most women with newly diagnosed breast cancer are of luminal type and will be offered 5-10 years of adjuvant endocrine therapy. Many women will not have a survival benefit from this therapy and 30% or more will struggle with side effects and quality of life issues. Breast Cancer Index (BCI) is a genomic biomarker for early-stage, ER+ breast cancer and has been validated to assess risk of late (5-10 yr) distant recurrence and predict likelihood of benefit from extended (&amp;gt;5y) endocrine therapy utilizing the HoxB13/IL17BR(H/I) ratio. H/I has also been shown to predict benefit from endocrine therapy in the early adjuvant setting. The objective of this study was to characterize the impact of BCI on endocrine therapy decision-making for early-stage breast cancer patients. Methods: Data was collected retrospectively from patients with early-stage luminal breast cancer treated at Breastlink who underwent BCI testing between 10/2014-5/2015. The impact of BCI test results were analyzed for 3 indications: 1) initiation of endocrine therapy for patients considering no adjuvant treatment; 2) patients 6 mo-4y post diagnosis struggling with side effects and desiring to discontinue endocrine therapy; and 3) patients beyond 4 years of adjuvant hormonal therapy deciding whether to extend therapy for an additional 5 years. Results: One hundred patients underwent BCI testing with median age 53 (range 35-77). The BCI assay was utilized in 14 cases at diagnosis, 54 cases at 6 mo-4y during therapy, and 32 cases at &amp;gt;4y post-diagnosis. In patients tested at time of diagnosis, 10/11 that were low risk for late recurrence and low likelihood of benefit from endocrine therapy chose not to initiate therapy, and 2/2 patients were high risk/high likelihood to benefit initiated therapy. One patient, a 72 year-old with low risk and high likelihood to benefit, declined therapy. In patients tested between 6 mo-4y on therapy, 30/30 patients were low risk and low likelihood of benefit chose to stop endocrine therapy, and 11/11 patients were high risk and high likelihood of benefit chose to continue. Of 7 patients that were low risk but high likelihood of benefit, 5 continued therapy. All 6 patients that were high risk but low likelihood of benefit chose to stop therapy. Of 32 patients tested after 4 years of adjuvant therapy, 13/13 were low risk and low likelihood of benefit chose to stop endocrine therapy at 5 years, and 8/8 were high risk and high likelihood of benefit chose to extend therapy to 10 years. All 5 patients that were high risk but low likelihood of benefit elected to stop, and 3/6 patients that were low risk but high likelihood to benefit extended therapy. In total, endocrine therapy treatment decision making aligned with predictive (H/I) results in 93/100 patients. Conclusion: The BCI test was instrumental in assisting almost all women in their decision to receive or maintain adjuvant hormonal therapy and 67% of women discontinued or declined hormonal therapy based on test results. All patients with high risk and high predictive benefit on BCI assay chose to pursue adjuvant endocrine therapy. Oncologists can use BCI in their algorithms of delivering personalized cancer care. Citation Format: Link JS, Buck LJ, Kapoor NS. The breast cancer index as a tool in decision making for adjuvant hormonal therapy in early luminal breast cancer: Initiation, withdrawal and continuance. [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 P5-08-10.