Breast cancer management is shifting towards personalized treatment regimens, particularly for early-stage, hormone receptor positive (HR+) invasive breast cancer (IBC) patients following breast conserving surgery (BCS) where locoregional recurrence (LRR) rates are low. A critical unmet need is the development of tools that can both improve prognostic risk assessment and identify which patients are likely to benefit or not benefit from adjuvant radiation therapy (RT). Herein we developed and cross validated a novel multi-omic assay to assess LRR risk and expected RT benefit for early-stage HR+/HER2-negative IBCs. A retrospective multi-institutional cohort of 922 patients (T1-2, N0-1, HR+, HER2-) treated with definitive breast conserving surgery (BCS) with or without adjuvant treatment was used to develop and cross-validate a test to predict IBC LRR after BCS ± RT. Treatment assignment was not randomized. The test integrated NGS and proteomic assay data using two biosignatures to generate results: a Decision Score (DS) to predict 10-year LRR prognosis and a radiation resistance index (RRI) to predict differential RT effect on LRR. Associations between DS and RRI with LRR risk and RT interaction were tested using multivariable Cox models. Increasing continuous DS was associated with increasing LRR risk (HR 3.4 per 5 units; p<.001, n = 922) after adjusting for clinicopathologic risk factors, while RT was associated with reduced LRR risk (HR 0.2; p < .001). Increasing continuous RRI was associated with increasing LRR risk for patients treated with RT (HR = 3.1 per 5 units; RT: RRI pinteraction = 0.002). Biosignature utility was demonstrated for categorical risk groups, which were also associated with differential RT benefit. DS Elevated Risk patients (DS > 5) had higher LRR risk without RT (HR = 4.8; p = .0014) with corresponding 10-year risks of 24

e12566 Background: Adjuvant radiation therapy (RT) has been a standard component of breast conserving therapy (BCT), demonstrating a reduction in local regional recurrence (LRR) and an improvement in breast cancer mortality. In addition, endocrine therapy (ET) has been shown to have both ipsilateral and contralateral risk reduction benefits as well as mortality benefits. Given the benefits of RT and ET are not uniform for all patients, locoregional therapy for early stage- hormone receptor positive (HR+) breast cancer continues to evolve with a focus on individualized risk stratification; genomic and multiomic approaches are increasingly being considered to support informed decision making for patients, allowing clinicians to optimize treatment and identify patients who will have a significant benefit from RT and/or ET and those who will not. Methods: A group of 782 patients (T1/2, N0/1, HR+, HER2-) who underwent breast conservation surgery (BCS) between 1986-2022 were identified from a multi-institutional cohort of which 630 were 50 years or older and node negative. A multi-omic biosignature combining proteomic and genomic biomarkers (AidaBreast, PreludeDx, Laguna Hills, CA) was developed and cross-validated to calculate an individualized Decision Score (DS) on a 10-point scale and corresponding 10-year LRR risk for prognosis. The association between the DS, 10-yr LRR rate, and RT and ET benefit was assessed using multivariable (MVA) Cox proportional hazards. Results: The median age was 66 years old with 74% (465/630) of patients receiving RT and 37% (234/630) receiving ET, and 27% (n=171) receiving both ET and RT. Median follow up was 10 years. 39% (n=246) of patients had a Low Risk Decision Scores (DS≤4) and on MVA had no significant reduction in LRR risk with RT (HR= 0.92; p=.90) or ET (HR= 1.5; p=.65). The corresponding 10-year LRR risks were ≤5% independent of treatment with ET or RT. In contrast, patients with high Decision Scores (DS>4) (61%, n=384) had a significant reduction in LRR risk with RT (HR= 0.5, p=0.03) and had a trend toward reduced LRR rate with ET of (HR=0.5; p=0.16) with corresponding 10-year LRR risks of 20% (95%CI 10%, 28%) vs 12% (95%CI 7%,16%) without vs with RT. On MVA, neither age, grade, nor size were associated with LRR risk (p≥.4) after adjusting for DS. Conclusions: The multi-omic biosignature (AidaBreast, PreludeDX, Laguna Hills, CA) stratifies early-stage HR+ HER2-negative invasive breast cancer patients into those with little to no LRR benefit from RT or ET over 10-years versus those who have a meaningful reduction in LRR risk with adjuvant RT.

BACKGROUND:Genetics may influence symptoms experienced by breast cancer survivors (BCS) by moderating the effects of stress-reducing interventions, including the Mindfulness-Based Stress Reduction (MBSR(BC)) program, to reduce symptom severity. As part of a larger clinical trial, the aim of this study was to evaluate genetic variants as moderators of MBSR(BC) on improvements among BCS in cognitive functioning and symptoms. METHODS:BCS (n = 128) were randomized to MBSR(BC) or the Breast Cancer Education Support Program. Objective neuropsychological and subjective measures of cognitive performance, and psychological and physical symptoms were collected at baseline, 6, 12, and 26 weeks. Linear mixed models were implemented to identify MBSR(BC)'s effects over time. A total of 22 single nucleotide polymorphisms (SNPs) from 20 genes known to be related to these symptoms were investigated using genomic DNA. These SNPs were tested as moderators of MBSR(BC) program effects. RESULTS:Results showed MBSR(BC) participants experienced significantly greater benefits in cognitive functioning, however, the level of benefit varied based on one's genetic profile. Effects sizes, consistency across similar measures were investigated. Among 22 candidate SNPs, rs4680 in COMT, rs1800497 in ANKK1, and rs6277 in DRD2 demonstrated the strongest, most consistent positive effects in moderating MBSR(BC)'s impact on cognitive outcomes. CONCLUSIONS:Although the effects were small, this translational research may potentially identify BCS with genotypes that would be most influenced by the MBSR(BC) program. These results may be used to develop personalized intervention programs tailored to the genetic profile of each breast cancer survivor who received chemotherapy or chemotherapy and radiation. TRIAL REGISTRATION:ClinicalTrials.gov, https://www.ClinicalTrials.gov Registration Number: NCT02786797.

A correction to this paper has been published: https://doi.org/10.1245/s10434-021-10138-3

Introduction: The Mindfulness-Based Stress Reduction program for breast cancer survivors (MBSR [BCs]) is a stress-reducing program designed to increase cognitive functioning through four meditational practices. This randomized clinical trial aimed to determine if improvements in cognitive functioning and perceived cognitive abilities achieved from the MBSR(BC) were mediated through increased mindfulness, decreased rumination, and decreased perceived stress.Methods: Breast cancer survivors (BCSs) who met inclusion criteria of stage I, II, or III BC and received either chemotherapy (CT) or both CT and radiation were randomized to either the 6-week MBSR(BC), or Breast Cancer Education Support (BCES) program, or to a usual care (UC) regimen. Analysis of covariance was first implemented to identify potential mediators, followed by a formal mediational analysis to evaluate the effects of MBSR(BC) on 6-, 12-, and 26-week outcomes.Results: After consent, 212 BCS were randomized to MBSR(BC) (n = 91), BCES (n = 90), or UC (n = 31). The mean age was 56.5 and the majority of the BCS, 73.1%, were White and non-Hispanic. Results showed increases in "observing" as part of mindfulness as a potential mediator of MBSR(BC) effects on impairments on quality of life and logical memory at 6 months relative to UC. No mediation effects were identified for outcomes measured at 6 or 12 weeks and also when MBSR(BC) was compared with the BCES program.Discussion: These results partially supported our hypothesis that improvement in cognitive functioning would occur through increased mindfulness. Although few mediating relationships were identified, results showed a relationship between mindfulness and cognitive functioning. Both mediating relationships occurred through increases in "observing," a subconcept of "mindfulness," when compared to the MBSR(BC) with UC at 6 months. This study shows that mediators may help "optimize" clinical therapeutic treatment effects, thus contributing to the advancement of science. Trial Registration: ClinicalTrials.gov, www.ClinicalTrials.gov. Registration Number: NCT02786797.

Background Neoadjuvant chemotherapy (NCT) increases the feasibility of surgical resection by downstaging large primary breast tumors and nodal involvement, which may result in surgical de-escalation and improved outcomes. This subanalysis from the Multi-Institutional Neo-adjuvant Therapy MammaPrint Project I (MINT) trial evaluated the association between MammaPrint and BluePrint with nodal downstaging. Patients and Methods The prospective MINT trial (NCT01501487) enrolled 387 patients between 2011 and 2016 aged ≥ 18 years with invasive breast cancer (T2–T4). This subanalysis includes 146 patients with stage II–III, lymph node positive, who received NCT. MammaPrint stratifies tumors as having a Low Risk or High Risk of distant metastasis. Together with MammaPrint, BluePrint genomically (g) categorizes tumors as gLuminal A, gLuminal B, gHER2, or gBasal. Results Overall, 45.2% ( n = 66/146) of patients had complete nodal downstaging, of whom 60.6% ( n = 40/66) achieved a pathologic complete response. MammaPrint and combined MammaPrint and BluePrint were significantly associated with nodal downstaging ( p = 0.007 and p < 0.001, respectively). A greater proportion of patients with MammaPrint High Risk tumors had nodal downstaging compared with Low Risk ( p = 0.007). When classified with MammaPrint and BluePrint, more patients with gLuminal B, gHER2, and gBasal tumors had nodal downstaging compared with HR+HER2−, gLuminal A tumors ( p = 0.538, p < 0.001, and p = 0.013, respectively). Conclusions Patients with genomically High Risk tumors, defined by MammaPrint with or without BluePrint, respond better to NCT and have a higher likelihood of nodal downstaging compared with patients with gLuminal A tumors. These genomic signatures can be used to select node-positive patients who are more likely to have nodal downstaging and avoid invasive surgical procedures.

Background: The role of adjuvant radiotherapy (RT) following breast conserving surgery (BCS) for women with ductal carcinoma in situ (DCIS) remains controversial. Although there is Level 1 evidence supporting the use of RT in reducing the risk of local recurrence, prognostic and predictive tools are needed to better stratify individual risks and benefits of RT. The DCISionRT® Test (PreludeDx, Laguna Hills, CA) is a 7-gene predictive biosignature that uses tumor biology in conjunction with clinicopathologic factors. The test provides a validated score (DS) for women receiving BCS that assesses 10-year risk of DCIS recurrence and development of invasive breast cancer with and without adjuvant RT. We established a registry to evaluate the decision impact of the 7-gene predictive biosignature on DCIS treatment recommendations. Methods: The PREDICT study is a prospective, multi-institutional registry for patients who received DCISionRT testing as part of their routine care. The registry includes females 26 and older who are diagnosed with DCIS and are candidates for BCS and eligible for RT or systemic therapy. Treating physicians completed treatment recommendation forms before and after receiving test reports to capture surgical, radiation and hormonal treatment (HT) recommendations and patient preferences. The primary endpoint is to identify the proportion of patients where testing led to a change in RT recommendation. Additional analyses include changes in recommendations in patient subgroups based on clinicopathologic factors or clinician specialty. Results: Analysis was performed in 2,308 patients treated at 63 clinical sites. The median age of patients was 62 years, 18% were 50 or younger, nuclear grade was high in 33%, and tumor size was 2.5 cm or greater in 11%. Test results were DS Low Risk (DS ≤ 3) for 63% of women and 37% were DS Elevated Risk (DS > 3). Overall, RT recommendation (yes/no) was changed for 38% of women after the 7-gene biosignature testing and HT recommendation was changed for 11%. There was a net decrease in RT recommendation from 71% pre-assay to 53% post-assay (p< 0.001), where RT recommendations decreased 53% in DS Low Risk patients but increased 25% in DS Elevated Risk patients. Surgeons were more likely to change their RT recommendation (47%) than radiation oncologists (35%). When test results indicated DS Elevated Risk, both surgeons (79%) and radiation oncologists (88%) were likely to recommended RT, but when the results were DS Low risk, surgeons were more likely than radiation oncologists to recommend omitting RT (82% vs. 60%, respectively). Compared to traditional clinicopathologic features, the factor most strongly associated with RT recommendation was the biosignature result with other factors of importance being patient preference, tumor size and grade. Conclusions: This analysis demonstrates significant changes in recommendations to add or omit RT based on the 7-gene predictive biosignature in 2,308 patients. The integration of DCISionRT into clinical decision processes has substantial impact on recommendations aimed at optimal management to prevent over- or under-treatment. Table 1. Impact of the 7-gene predictive biosignature on adjuvant radiation recommended by clinicopathologic features. Citation Format: Pat Whitworth, Steven C. Shivers, Chirag Shah, Rakesh Patel, Karuna Mittal, Troy Bremer, Charles Cox. Changes in treatment recommendation for patients with Ductal Carcinoma In Situ using a 7-gene predictive biosignature: Analysis of the PREDICT Study [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 P4-02-02.

Background: The role of adjuvant RT following breast conserving surgery (BCS) for women with ductal carcinoma in situ (DCIS) remains controversial. Although there is level I evidence supporting the role of RT in reducing the risk of local recurrence, prognostic and predictive tools are needed to better stratify individual risks and benefits of RT. The DCISionRT® Test (PreludeDx, Laguna Hills, CA) is a biosignature that uses individual tumor biology in conjunction with clinical and pathologic risk factors. The test provides a validated score (DS) for women receiving BCS that assesses 10-year risk of DCIS recurrence and development of invasive breast cancer with and without adjuvant RT. We established a registry to evaluate the decision impact of DCISionRT on DCIS treatment recommendations. Methods: The PREDICT study is a prospective, multi-institutional registry for patients who received DCISionRT testing as part of their routine care. The registry includes females 26 and older who are diagnosed with DCIS and are candidates for BCS and eligible for RT or systemic therapy. Treating physicians completed treatment recommendation forms before and after receiving test reports to capture surgical, radiation and hormonal treatment (HT) recommendations and patient preferences. The primary endpoint is to identify the proportion of patients where testing led to a change in RT recommendation. Additional analyses include changes in recommendations in patient subgroups based on clinicopathologic factors or type of treating physician. Results: Analysis was performed in 969 patients treated at 55 sites who had definitive BCS and subsequent DCISionRT testing. The median age of patients was 62 years, 19% were 50 or younger, nuclear grade was high in 31% and tumor size was 2.5 cm or greater for 11%. Test results were DS Low risk (DS ≤ 3) for 63% of women and 37% were DS Elevated risk (DS > 3). Overall, RT recommendation (yes/no) was changed for 40% of women after DCISionRT testing and HT recommendation was changed for 11%. There was a net decrease in RT recommendation from 69% pre-assay to 50% post-assay (p<0.001). RT recommendation decreased by 42% in DS Low risk patients, but increased 22% in DS Elevated risk patients. Among physicians, surgeons were more likely to change their RT recommendation (49%) than radiation oncologists (38%). When test results indicated DS Elevated risk, both surgeons (82%) and radiation oncologists (91%) were likely to recommended RT, but when the results were low risk, surgeons were more likely than radiation oncologists to recommend omitting RT (83% vs. 68%, respectively). Conclusions: This interim analysis demonstrates a significant percent change in recommendations to add or omit RT based on DCISionRT results in 969 patients. Compared to traditional clinicopathologic features, the factor most strongly associated with RT recommendation was the DCISionRT result with other factors of importance being patient preference, tumor size and grade. The integration of DCISionRT into clinical decision processes has substantial impact on recommendations aimed at optimal management to prevent over- or under-treatment. TABLE 1. Impact of DCISionRT on adjuvant radiation recommended by clinicopathologic features.RT recommendedPre- to post-test change in RT recommendedTotal change in RT recommendedClinical factorNPre-test(%)Post-test(%)Net change (%)Yes to no (%)No to yes (%)Overall change (%)95% CIp-ValueAge, years< 501648148-3243133730-45%<0.001≥ 508056651-1642374137-44%<0.001Grade1 or 26656144-1650354440-47%<0.00133048764-2332333227-37%<0.001Tumor size≤ 2.5 cm8596648-1845354238-45%<0.001> 2.5 cm1109269-2327222619-35%<0.001RTOG 9804 criteria‘Good risk’5005541-1452344440-49%<0.001Not ‘good risk’4598460-2436353632-40%<0.001 Citation Format: Steven C Shivers, Pat W Whitworth, Rakesh Patel, Troy Bremer, Charles E Cox. Interim analysis of the PREDICT Registry: Changes in treatment recommendation for a biologic signature predictive of radiation therapy (RT) benefit in patients with DCIS [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 P2-08-12.

Abstract Background: Elderly breast cancer (BC) patients are an understudied population, with limited evidence regarding treatment options and outcomes and a lack of research involving prognostic multigene assays for this group. One study in patients 65-89 years old with an Oncotype DX Recurrence Score ≥ 26 concluded that gene expression profiling tests have limited utility in elderly patients, and should only be used for patients aged 65-74 with no/low to moderate comorbidities and not for patients ≥ 75. In this study, the 70-gene risk of distant recurrence signature, MammaPrint (MP), and 80-gene molecular subtyping signature, BluePrint (BP), were evaluated in both the neoadjuvant and adjuvant settings in elderly patients with early stage BC. Methods: This analysis included 211 BC patients classified as cT2-4N0-3M0 (T2 > 3.5 cm if N0) who received neoadjuvant chemotherapy and enrolled in the Multi-Institutional Neoadjuvant Therapy MammaPrint Project (MINT) study from 2011-2016. Lymph node (LN) involvement was established following neoadjuvant treatment. The second analysis included 517 early stage BC patients with 0-3 positive LNs who enrolled in the community based cohort study (COPPER) from 2009-2016. Patients were given adjuvant treatment following standard of care. Patients from both cohorts were divided into age at diagnosis groups: < 65, 65-74, and > 74. MP stratified patients into either Low Risk (LR) or High Risk (HR) groups. BP classified patient samples into Luminal, HER2, or Basal subtype. Kaplan Meier analysis and log-rank test were used to assess differences in overall survival (OS) and distant metastasis free survival (DMFS). Clinical risk assessment based on the MINDACT trial algorithm was performed. Results: From MINT, 35 patients were ≥ 65 years old; 80% were HR and 20% were LR. Pathological complete response (pCR) was achieved in 36% (10/28) of elderly HR patients, of whom 70% were HER2 and 30% were Basal by BP. Nodal downstaging occurred in 55% (11/20) of LN positive elderly HR patients, of whom 64% (7/11) achieved pCR. BP classified patients with nodal downstaging as HER2 (55%), Basal (36%), or Luminal (9%). Importantly, pCR and nodal downstaging were more likely to be achieved in HR tumors and correlated with BP subtype in both young and elderly patients. From the COPPER cohort, 77% of HR patients 65-74 years old received chemotherapy (CT), whereas 74% of LR patients omitted CT. Of patients > 74, 49% of HR patients received CT, whereas 75% of LR patients omitted CT. OS and DMFS probabilities indicated good survival outcomes in LR patients that omitted CT and HR patients that received CT, with no significant difference between age groups. A majority of HR patients treated with CT and over 1/3 of LR patients that omitted CT had high clinical risk. Interestingly, among all patients that had a metastasis event, mortality was less likely to occur in patients that received dose dense AC (doxorubicin and cyclophosphamide). Conclusion: MP and BP may identify HR elderly patients who are likely to achieve nodal downstaging and pCR. Elderly patients were safely spared or assigned adjuvant CT based on MP results independent of clinical risk. Furthermore, these data are in line with previous studies that suggest similar survival benefits between older and younger patients who are candidates for aggressive CT regimens. MP and BP elucidate information about tumor biology and provide prognostic value, which may help inform treatment decisions, independent of patient age. MINTAge group< 6565-74> 74MP resultHRLRHRLRHR# of patients152242177% of patients with pCR35% (53/152)033% (7/21)043% (3/7)# of LN+ patients103181456% of LN+ patients with nodal downstaging49.5% (51/103)22% (4/18)50% (7/14)067% (4/6)% of LN+ patients with pCR & nodal downstaging65% (33/51)071%(5/7)050%(2/4)COPPERAge group< 6565-74> 74MP resultHRLRHRLRHRLR# of patients1409988665569# of patients received CT121256813278# of patients omitted CT116717492052# of patients with unknown treatment873489Groups treated based on MPHR treated with CTLR omitted CTAge group< 6565-74> 74< 6565-74> 745-yr DMFS probability (95% CI)91% (80.2-96.7)87% (60.2-91.4)87% (55.2-96.6)100%98% (84.3-99.7)94% (75.9-98.5)5-yr OS probability (95% CI)94% (80.2-98.2)96% (83.4-98.9)86% (54.7-96.5)100%98% (84.3-99.7)97% (80.4-99.6)% Clinical high risk83% (100/121)76% (52/68)63% (17/27)34% (23/67)37% (18/49)35% (18/52) Citation Format: Peter W. Blumencranz, Mehran Habibi, Lisa Blumencranz, Andrea Menicucci, Shiyu Wang, Amy Truitt, William Audeh, Jolanta L. Baginski, Steven Shivers, Geza Acs, Charles E. Cox, MINT Investigators Group. Mammaprint and blueprint as prognostic indicators for elderly patients with early stage breast cancer [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 PS6-41.

Abstract BACKGROUND: When considering health-related, quality-of-life and monetary costs associated with post-surgical treatments for women diagnosed with Ductal Carcinoma In Situ (DCIS), there remains a need for prognostic and predictive tools to help design individual treatment planning. DCISionRT (PreludeDx, Laguna Hills, CA) is a validated biologic signature to assess the 10-year event risk for DCIS patients managed with breast conserving surgery (BCS). The 10-year risks are provided separately for patients treated with and without adjuvant radiation therapy (RT) after BCS. The study was designed to measure the change in adjuvant RT recommendation. This is a planned interim analysis of the study, which will eventually comprise up to 2,500 patients and 100 sites. METHODS: The registry includes females over the age of 25 who are candidates for breast conserving surgery and eligible for RT. Survey forms are completed pre- and post-DCISionRT test to capture treatment recommendations and patient preferences. This interim analysis was performed to assess changes in RT recommendation for patients treated with BCS in different clinicopathologic subgroups. Specifically, ‘good risk’ profiles were based on the RTOG 9804 and ECOG 5194 study designs. RTOG 9804 like criteria was screening detected tumors with nuclear grade of 1 or 2, size of ≤ 2.5 cm, and clear (≥ 2 mm) surgical margins. ECOG 5194 like criteria was tumors with nuclear grade of 1 or 2, size of ≤ 2.5 cm, and clear surgical margins, or nuclear grade of 3, size of ≤ 1 cm, and clear surgical margins. Statistics were provided as percentages and counts, and McNemar’s test was used to assess change in RT with a p-value of <0.05 considered statistically significant. RESULTS: There were 513 patients from 32 sites with testing completed after treatment with BCS. Of these patients, 16% were ≤ 50 years of age, 60% were ≥ 60 years of age, and 26% were ≥ 70 years of age. The DCIS tumor nuclear grade was high in 32% of patients, and the size of the tumor was ≤ 1 cm for 68% of patients. There were 49% of patients who met RTOG 9804 like criteria, 51% who met the ECOG 5194 (grade 1 or 2) criteria, and 45% of patients who met the ECOG 5194 (grade 3) criteria. RT was recommended to 52% and 53% patients for RTOG 9804/ECOG 5194 (grade 1 or 2) criteria pre-testing, and 42% post-testing. For ECOG 5194 (grade 3) like criteria, 64% of patients were recommended RT pre-test, and 40% were recommended RT post-test. In all criteria groups, for patients whom were initially recommended RT pre-test, 51% to 54% were not recommended RT post-test, while patients initially not recommended RT pre-test, 25% to 37% were recommended RT post-test. Overall, the post-test RT recommendation was significantly changed from between 42% and 46% for patients with ‘good-risk’ clinicopathologic criteria. CONCLUSIONS: The PREDICT study interim analysis demonstrates a significant absolute overall change post DCISionRT testing for RT recommendation in patients with ‘good-risk’ clinicopathology. RT recommendations were changed post-test for 42% to 46% of patients meeting RTOG 9804/ECOG 5194 like criteria. Integration of DCISionRT testing had a significant impact on the RT recommendations aimed at reducing overtreatment and minimizing undertreatment. Table 1. Pre-Post DCISionRT Impact by ‘good-risk’ criteria.n% RTPre-testYes% RTPost-test Yes% RTPre-Yes, Post-No% RTPre-No, Post-Yes% Total Decision Change95% CIp-valueRTOG 9804 criteriaGrade 1 or 2, Size ≤ 2.5 cm, screen detected, wide margins2525242543746%40 - 52%1.2E-02ECOG E5194 criteriaGrade 1 and 2, Size ≤ 2.5 cm, wide margins2625342533645%39 - 51%0.010Grade 3, Size ≤ 1 cm, wide margins2316440512542%36 - 48%2.4E-08 Citation Format: Chirag Shah, Frank Vicini, Steven C Shivers, Pat W Whitworth, Rakesh Patel, Charles E Cox, Troy Bremer. Clinical utility of a biologic signature to assess DCIS recurrence risk in patients meeting ‘good-risk’ criteria (RTOG 9804, ECOG 5194): Interim analysis of the DCISionRT PREDICT study [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 PS6-17.

Abstract Background: The main goal of the Multi-Institutional Neo-Adjuvant Therapy MammaPrint (MINT) project was to determine the predictive power of the combination of the molecular assays MammaPrint and BluePrint (Agendia Inc., Irvine, CA) for chemosensitivity as measured by complete pathological response (pCR) in patients with locally advanced breast cancer (LABC). MammaPrint is a 70-gene microarray-based assay that classifies each breast cancer patient as low or high risk to develop metastases within 10 years after diagnosis. The BluePrint test is an 80-gene molecular subtyping profile that discriminates between luminal, basal and HER-2 subtypes. Methods: After appropriate IRB approval, 270 female patients with histologically-proven invasive breast cancer and no distant metastases were enrolled in this study. Patients had a clinical tumor classification of T2-T4 with 0-3 positive lymph nodes. DCIS or LCIS was allowed in addition to invasive cancer at the T2 or T3 levels. At least one lesion had to be accurately measured in two dimensions utilizing mammogram, ultrasound, or MRI images to define specific size and validate pCR. Patients were required to have adequate bone marrow reserves, renal function and hepatic function, as determined by standard blood and serum measurements. Patients under 18 years of age or those with confirmed metastatic disease, inflammatory breast cancer, any serious uncontrolled intercurrent infections, or other serious uncontrolled concomitant disease were excluded. Patients with any prior chemotherapy, radiotherapy, or endocrine therapy for the treatment of breast cancer were also excluded. Tumor samples were collected via incisional or core needle biopsy and shipped to Agendia for processing of the MammaPrint and BluePrint gene panels, as well as whole human genome expression microarrays. Comparison of response rates between MammaPrint and BluePrint molecular subtypes was conducted using Pearson Chi-square test with chemo-responsiveness measured as a binary response: pCR or residual disease. Results: Of 270 patients enrolled, 56 did not have TNM or RCB staging information reported in the case report form and/or were not submitted for central pathology review. Of 214 patients evaluated by central pathology review, 68 (32%) exhibited a pCR. Patients with a high risk MammaPrint result had a higher pCR rate (37%) compared to patients with a low risk MammaPrint (0%). And patients with a HER-2 or basal molecular subtype by BluePrint had significantly higher rates of pCR (62%, 37%, respectively). Conclusion: Upfront evaluation of LABC tumors using the combination of MammaPrint and BluePrint can help in the clinico-pathologic evaluation to determine which patients are more likely to benefit from neo-adjuvant chemotherapy, ranging from expected minimal response in Luminal A to substantial responses for HER2-type and Basal-type tumors. Additional studies to evaluate the prognostic and/or predictive values of additional gene panels from the whole human genome microarrays are underway. Rate of pCR in MammaPrint and MammaPrint/BluePrint groupsGroupsResidual DiseasepCRP valueMP Risk GroupLow Risk27 (100%)0 (0%)0.0004High Risk114 (63%)67 (37%)BP subtypeBasal42 (63%)25 (37%)2 x 10-9HER220 (38%)33 (62%)Luminal A26 (100%)0 (0%)Luminal B53 (85%)9 (15%) Citation Format: Brian Longbottom, Steven C Shivers, Geza Acs, Charles E Cox. Combined use of MammaPrint and BluePrint assays to evaluate patients for response to neo-adjuvant chemotherapy for locally advanced breast cancer [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 PS6-30.

Abstract Background: Male breast cancer (MaBC) is rare, comprising <1% of all breast cancers in the United States. The low incidence of MaBC limits the ability to conduct clinical trials specifically for this population. Due to the paucity of research on MaBC, current understanding regarding MaBC biology, pathology, and treatment strategies has been primarily based on evidence extrapolated from research on female breast cancer (FBC) patients. Traditional diagnostic biomarkers such as ER, PR, and HER2, as well as newer multi-gene prognostic signatures, are employed when making treatment decisions for both MaBC and FBC. However, limited empirical data is available to support the use of identical laboratory biomarkers and molecular signatures in both MaBC and FBC. The 70-gene risk of distant recurrence signature, MammaPrint (MP), and the 80-gene molecular subtyping signature, BluePrint (BP), are commonly used to help make treatment decisions for both MaBC and FBC patients. To support the clinical utility of MP and BP in MaBC, this study aims to elucidate whether significant molecular biological differences exist between MaBC and FBC. To address this knowledge gap, we evaluated and compared 1) MP index results within Low Risk (LR) and High Risk (HR) groups, 2) MP and BP gene expression, and 3) differentially expressed genes within the full genome and their associated biological pathways between tumors from MaBC and FBC. Methods: This analysis included a total of 817 breast tumor samples sent to Agendia, Inc. (Irvine, CA) for MP and BP testing. Full-transcriptome microarray data were available for 1) a subset of 400 post-menopausal FBC patients enrolled in the FLEX Registry (NCT03053193) and 2) 80 MaBC pateints, 32 of whom enrolled in the FLEX registry and 48 non-study patients for whom data were limited to metadata and quality metrics routinely captured for diagnostic testing. Data from all patients were de-indentified. Differences in mean MP indices between FBC (N=400) and MaBC (N=417) according to MP Risk classification (LR or HR) were analyzed using a Z-test. Differential gene expression analysis was performed using the R-limma package in which gene expression data were quantile normalized. Pathway analyses were performed using GOseq. Differentially expressed genes (DEGs) were identified between FBC (N=400) and MaBC (N=80) for whom full transcriptome microarray data were available. DEGs were defined as those with a fold change of > 2 and an adjusted P value of < 0.05. Results: All patients in this study had hormone positive, HER2 negative early-stage breast cancer. There was no statistical difference in the average MP index between MaBC and FBC classified as MP LR (P=0.273) or those classified as MP HR (P=0.692). Gene expression comparison revealed 166 DEGs between MaBC (N=80) and FBC (N=400), 99 DEGs between MP HR MaBC (N=42) and MP HR FBC (N=200), and 290 DEGs between MP LR MaBC (N=38) and MP LR FBC (N=200). Pathway analyses revealed that downregulated genes in MaBC compared to FBC enriched to immune-related functions, including B-cell mediated immunity, whereas upregulated genes were associated with hormone metabolic processes. In all comparisons, expression of MP or BP genes was not significantly different. Conclusions: We found similar MP index distributions between MaBC and FBC. Importantly, differential gene expression between MaBC and FBC provides novel insight into the mechanisms underlying MaBC. Although these data reveal biological distinctions between male and female breast cancer, MP and BP assay performance is preserved across both groups. Further studies are needed to assess clinical outcomes; however, these findings support the use of MP risk of recurrence assay and BP molecular subtyping assay for prognosis and informing treatment decisions in MaBC. Citation Format: Jennifer Crozier, Julie Barone, Kalyan Banda, Beth Lesnikoski, Robert Maganini, Sami Diab, Ian Grady, Thomas Lomis, Charles Cox, Amy Truitt, Benjamin Nota, Andrea Menicucci, Erin Yoder, William Audeh, FLEX Investigators Group. Differential gene expression analysis and clinical utility of MammaPrint and BluePrint in male breast cancer patients [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 PS14-11.

Abstract Background/Objective: Breast cancer incidence in Asian populations has increased in recent years, and variation in prognosis and tumor subtypes indicates that further study is warranted to characterize these differences and identify actionable targets. Patients of Asian ancestry are underrepresented in US registries, and few studies have characterized molecular profiles for these patients. In the current analysis, we assess clinical, pathological, and molecular profiles from self-reported Asian breast cancer patients (AS), in comparison with age-matched Caucasian (CA) and African American patients (AA), to evaluate the influence of Asian ancestry on differential gene expression in breast tumors. Methods: This meta-analysis included cohorts of self-reported AS, CA, and AA with early-stage, invasive breast cancer (EBC) prospectively enrolled in the US from 2011 to 2020 in FLEX (NCT03053193), MINT (NCT01501487), or IMPACt (NCT02670577) trials. AS were significantly younger (mean, 55 years) than CA (mean, 61 years, p<0.001) or AA (mean, 59 years, p=0.005); thus, an age-matched subset was selected for analyses. 70-gene signature (MammaPrint, MP), 80-gene signature (BluePrint, BP), and clinical-pathological features were compared among age-matched AS (n=103), CA (n=103), and AA (n=100). Whole-genome expression data were quantile normalized using R limma package, and differentially expressed genes (DEGs) were compared among AS (n=90), CA (n=102), and AA (n=96). DEGs with adjusted p-value <0.05 and log2 fold change > ± 0.5 were considered significant. Results: AS tumors were classified as 59% MP HR, compared with 44% HR in age-matched CA (p=0.08) and 64% HR in age-matched AA (p=0.17). AS had a significantly lower rate of obesity (16%, body mass index ≥30) compared with CA (41%) and AA (67%) (p<0.001). Tumors of AS were predominantly ductal carcinoma (84%), T1 (59%), grade 1 or 2 (70%), lymph-node negative (69%), ER+ (95%), and HER2-negative (89%). Distribution of ER, PR, and HER2 pathology and BP subtypes for AS were similar to CA but significantly different from AA (Table). Histologic tumor type, tumor grade, tumor stage, nodal stage, menopausal status, and frequency of Type 2 diabetes mellitus were not significantly different between AS and CA or AA. Whole-genome expression comparisons revealed 19 significant DEGs between AS and CA, and 45 significant DEGs between AS and AA. Immune-related genes, primarily those involved with B cell responses and signaling, were more highly expressed in AS compared with CA. Expression of genes related to cell-cycle pathways was greater in AS compared with AA. Conclusions: AS were significantly younger and more often pre/peri-menopausal at diagnosis compared with CA and AA, consistent with the literature. Most clinical-pathological factors were similar between age-matched groups, except for the obesity rate, which was significantly lower in AS than in CA or AA. Although not significant, AS had EBC that was more often MP HR than CA and less often HR than AA; studies with larger patient groups will help confirm these trends. The current analysis revealed different underlying gene expression pathways in AS compared with other ethnic groups, which may result in differential clinical outcomes. As genomic profiling data are not widely available for Asian American EBC patients, further analyses are warranted to elucidate these outcomes and identify appropriate therapeutic strategies. Pathology and Genomic Results(unknowns excluded)Asian (n=103)Caucasian (n=103)African American (n=100)p-valueAS vs. CAp-value AS vs. AAER status (IHC)ER Positive69 (94.5%)89 (98.9%)73 (80.2%)0.1250.010ER Negative4 (5.5%)1 (1.1%)18 (19.8%)PR status (IHC)PR Positive64 (87.7%)81 (90%)63 (69.2%)0.4110.006PR Negative9 (12.3%)9 (10%)28 (30.8%)HER2 (IHC/FISH)HER2 Positive3 (4.2%)3 (3.4%)13 (14.3%)0.1720.017HER2 Negative64 (88.9%)85 (95.5%)77 (84.6%)Equivocal5 (6.9%)1 (1.1%)1 (1.1%)MP/BP resultsLuminal A39 (40.6%)51 (53.7%)28 (30.4%)0.2320.043Luminal B45 (46.9%)38 (40.0%)42 (45.7%)HER2 (MP HR)7 (7.3%)4 (4.2%)5 (5.4%)Basal (MP HR)5 (5.2%)2 (2.1%)17 (18.5%) Citation Format: Margaret Chen, Ava Kwong, Carolyn Hendricks, Nina D'Abreo, Laura Lee, Hatem H. Soliman, Charles Cox, Heather M. Kling, Rajith Bhaskaran, Shiyu Wang, Andrea Menicucci, Sarah Untch, William Audeh, FLEX Investigators Group. Molecular profiles and clinical-pathological features of Asian early-stage breast cancer patients [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 PS7-69.

591 Background: Although advances in immunotherapy for the treatment of breast cancer have been minimal compared with other cancers, studies demonstrating tumor-infiltrating lymphocytes and immunomodulatory gene activation in the tumor microenvironment suggest the importance of antitumor immune responses in clinical outcomes. A 12-chemokine gene score has been shown to predict the presence of ectopic lymph node-like structures (ELN) in the tumor microenvironment and improved survival in melanoma, colon cancer, and breast cancer patients (Prabhakaran, 2017). Here, we evaluated this signature in an independent dataset of breast cancer patients treated with neoadjuvant chemotherapy. Methods: Tumor specimens used in this retrospective analysis (n = 92) were from breast cancer patients enrolled in either MINT (NCT0151487) or NBRST (NCT01479101) neoadjuvant registry trials from 2011 to 2016. Clinical data were captured with informed consent, and 70-gene signature (70-GS), 80-gene signature (80-GS), and full transcriptome data were generated by Agendia, Inc. Gene expression data were quantile normalized using R limma package. Principal component analysis (PCA) was performed on the normalized dataset using R princomp package. Chemokine score (CS) was defined as the first principal component values resulting from PCA. 70-GS/80-GS and clinical data were evaluated in relation to CS. CS were compared using Mann-Whitney test. Results: Of 92 breast tumors available for analysis, 84% were 70-GS High Risk (HR). Tumors were 39% Luminal-type, 24% HER2-type, and 32% Basal-type by 80-GS. HR tumors had higher CS than 70-GS Low Risk (LR) tumors (p < 0.001). 80-GS Basal-type, HER2-type, and Luminal B tumors had higher CS than Luminal A tumors (p < 0.01 for each comparison). High grade and ER-negative tumors seemed to have a high CS, although not significantly. Tumors from patients who achieved a pathological complete response (pCR) following neoadjuvant chemotherapy had higher CS than patients with residual cancer burden (p = 0.048). Conclusions: The current study demonstrated a significantly higher CS in 70-GS HR tumors and those which achieved pCR following neoadjuvant chemotherapy. Although further study is needed to evaluate the association of high CS with tumor-associated ELN, these results support previous work demonstrating that, although high CS is associated with aggressive clinical features, it also predicts superior clinical outcomes. The current study suggests validation of the 12-chemokine gene score in an independent dataset of breast cancer patients.