Hunt, Kelly K.

Objective: To evaluate the first 3 years of compliance with the American College of Surgeons Commission on Cancer (CoC) Operative Standards. Background: CoC implemented evidence-based standards to improve the quality of sentinel lymph node biopsy and axillary lymph node dissection for breast cancer (operative standards 5.3 and 5.4), wide local excision for melanoma (5.5), colectomy for colon cancer (5.6), proctectomy for rectal cancer (5.7), and pulmonary resection for lung cancer (5.8) at ∼1400 programs treating >74% of US cancer patients. Each operative standard defines a technical element of the operation and structured documentation. Methods: Compliance data are from site visits conducted between January 1, 2022, and December 31, 2024 (implementation/site visits began in 2021/2022 for 5.7 and 5.8 and 2023/2024 for 5.3–5.6). Compliance with each operative standard was determined by evaluation of 7 operative (5.3–5.6) or pathology (5.7, 5.8) reports. Deficiency in technical performance, documentation, or both was considered noncompliance. Results: Reviewers conducted 974 site visits of Comprehensive Community (44%), Community (23%), Academic Comprehensive (16%), network (12%), NCI-Designated Comprehensive (4%), and other (1%) cancer programs. Program compliance rates ranged from 53% to 88%. Documentation noncompliance was more common for standards 5.3 to 5.6 (based on operative reports), and technical noncompliance was more common for 5.7 and 5.8 (based on pathology reports). Compliance significantly (P=0.006) varied by program type for 5.8 (highest: 66% at NCI-designated Comprehensive programs; lowest: 37% at Community Cancer programs). Conclusions: Early compliance with CoC operative standards varied, indicating local and large-scale national quality improvement efforts are needed.

Importance Neoadjuvant systemic therapy (NST) has been associated with pathologic complete response (pCR) in up to 60% of breast cancers (BCs). The findings of this trial question the necessity of surgery. Objective To report preplanned 5-year efficacy outcomes evaluating radiotherapy alone without breast surgery in patients selected with image-guided vacuum assisted biopsy (VAB). Design, Setting, and Participants This single-arm, prospective, phase 2 nonrandomized clinical trial was conducted at 7 US medical centers and included women 40 years or older with cT1-2N0-1M0 ERBB2 -positive (formerly HER2 -positive) or triple-negative invasive BC who showed residual breast lesions after NST of less than 2 cm on imaging. Enrollment was from March 6, 2017, to November 9, 2021. Data analysis was from October to December 2024. Intervention Image-guided VAB of the tumor bed (9G with a minimum of 12 cores) was performed after standard NST. Patients with clinically node-negative disease at diagnosis and no residual cancer in the breast on post-NST VAB underwent whole-breast radiotherapy with a boost without breast or axillary surgery. Patients with initial documented nodal disease and a breast pCR on VAB underwent targeted axillary dissection, while those with residual cancer when undergoing VAB had standard breast and axillary surgery. Patients were monitored with physical examinations and mammography every 6 months. Main Outcome Measures The primary outcome was ipsilateral breast tumor recurrence. Results Fifty patients (median [IQR] age, 62 [55-77] years) were enrolled and underwent post-NST VAB. Twenty-nine (58%) and 21 (42%) patients had ERBB2 -positive and triple-negative invasive BC, respectively. Breast pCR on VAB was identified in 31 patients (62%; 95% CI, 47.2%-75.34%), and axillary pCR was identified among all 8 patients with initial nodal metastases and breast pCR on VAB who underwent targeted axillary dissection. At a median follow-up of 55.4 (IQR, 44.0-63.5) months, the ipsilateral breast tumor recurrence rate was 0%, and disease-free and overall survival rates were 100% for patients without breast surgery. Conclusions and Relevance The results of this nonrandomized clinical trial that reported preplanned 5-year outcomes suggest that omission of breast surgery in select patients after NST may be feasible, with no recurrences seen. More confirmatory studies are necessary before this new approach alters surgical practice. Trial Registration ClinicalTrials.gov Identifier: NCT02945579

Background: In the absence of high-quality evidence, there is a need for guidelines and multidisciplinary consensus recommendations on breast implant–associated anaplastic large-cell lymphoma (BIA-ALCL). The purpose of this expert consensus conference was to evaluate the existing evidence regarding the diagnosis and management of BIA-ALCL caused by textured implants. This article aims to provide evidence-based recommendations regarding the management and prevention of BIA-ALCL. Methods: A comprehensive search was conducted in the MEDLINE, Cochrane Library, and Embase databases, and supplemented by manual searches of relevant English-language articles and “related articles” sections. Studies focusing on breast surgery and lymphoma associated with breast implants were included for analysis. Meta-analyses were performed and reviewed by experts selected by the American Association of Plastic Surgeons using a Delphi consensus method. Results: A total of 840 articles published between January of 2011 and January of 2023 were initially identified and screened. The full text of 188 articles was assessed. An additional 43 articles were excluded for focus, and 145 articles were included in the synthesis of results, with 105 of them being case reports or case series. The analysis encompassed a comprehensive examination of the selected articles to determine the incidence, risk factors, clinical presentation, diagnostic approaches, and treatment modalities related to BIA-ALCL. Conclusions: Plastic surgeons should be aware of the elevated risks by implant surface type, implement appropriate patient surveillance, and follow the recommendations outlined in this statement to ensure patient safety and optimize outcomes. Ongoing research on the pathogenesis, genetic drivers, and preventative and prophylactic measures for BIA-ALCL is crucial for improving patient care. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, V.

Importance Adding fulvestrant to anastrozole (A+F) improved survival in postmenopausal women with advanced estrogen receptor (ER)–positive/ERBB2 (formerly HER2)–negative breast cancer. However, the combination has not been tested in early-stage disease. Objective To determine whether neoadjuvant fulvestrant or A+F increases the rate of pathologic complete response or ypT1-2N0/N1mic/Ki67 2.7% or less residual disease (referred to as endocrine-sensitive disease) over anastrozole alone. Design, Setting, and Participants A phase 3 randomized clinical trial assessing differences in clinical and correlative outcomes between each of the fulvestrant-containing arms and the anastrozole arm. Postmenopausal women with clinical stage II to III, ER-rich (Allred score 6-8 or >66%)/ERBB2-negative breast cancer were included. All analyses were based on data frozen on March 2, 2023. Interventions Patients received anastrozole, fulvestrant, or a combination for 6 months preoperatively. Tumor Ki67 was assessed at week 4 and optionally at week 12, and if greater than 10% at either time point, the patient switched to neoadjuvant chemotherapy or immediate surgery. Main Outcomes and Measures The primary outcome was the endocrine-sensitive disease rate (ESDR). A secondary outcome was the percentage change in Ki67 after 4 weeks of neoadjuvant endocrine therapy (NET) (week 4 Ki67 suppression). Results Between February 2014 and November 2018, 1362 female patients (mean [SD] age, 65.0 [8.2] years) were enrolled. Among the 1298 evaluable patients, ESDRs were 18.7% (95% CI, 15.1%-22.7%), 22.8% (95% CI, 18.9%-27.1%), and 20.5% (95% CI, 16.8%-24.6%) with anastrozole, fulvestrant, and A+F, respectively. Compared to anastrozole, neither fulvestrant-containing regimen significantly improved ESDR or week 4 Ki67 suppression. The rate of week 4 or week 12 Ki67 greater than 10% was 25.1%, 24.2%, and 15.7% with anastrozole, fulvestrant, and A+F, respectively. Pathologic complete response/residual cancer burden class I occurred in 8 of 167 patients and 17 of 167 patients, respectively (15.0%; 95% CI, 9.9%-21.3%), after switching to neoadjuvant chemotherapy due to week 4 or week 12 Ki67 greater than 10%. PAM50 subtyping derived from RNA sequencing of baseline biopsies available for 753 patients (58%) identified 394 luminal A, 304 luminal B, and 55 nonluminal tumors. A+F led to a greater week 4 Ki67 suppression than anastrozole alone in luminal B tumors (median [IQR], −90.4% [−95.2 to −81.9%] vs −76.7% [−89.0 to −55.6%]; P < .001), but not luminal A tumors. Thirty-six nonluminal tumors (65.5%) had a week 4 or week 12 Ki67 greater than 10%. Conclusions and Relevance In this randomized clinical trial, neither fulvestrant nor A+F significantly improved the 6-month ESDR over anastrozole in ER-rich/ERBB2-negative breast cancer. Aromatase inhibition remains the standard-of-care NET. Differential NET response by PAM50 subtype in exploratory analyses warrants further investigation. Trial Registration ClinicalTrials.gov Identifier: NCT01953588

ImportancePatients should have an active role in decisions about pursuing or forgoing specific therapies in treatment de-escalation trials.ObjectiveTo evaluate longitudinal patient-reported outcomes (PROs) encompassing decisional comfort and health-related quality of life (HRQOL) among patients who elected to enroll in a clinical trial evaluating radiotherapy alone, without breast surgery, for invasive breast cancers with exceptional response to neoadjuvant systemic therapy (NST).Design, Setting, and ParticipantsProspective, single-group, phase 2 clinical trial at 7 US medical centers. Women aged 40 years or older with invasive cT1-2 N0-1 M0 triple-negative or human epidermal growth factor receptor 2 (ERBB2)–positive breast cancer with no pathologic evidence of residual disease following standard NST enrolled from March 6, 2017, to November 9, 2021. Validated PRO measures were administered at baseline and 6, 12, and 36 months post-radiotherapy. Data were analyzed from January to February 2023.InterventionsPRO measures included the Decision Regret Scale (DRS), Functional Assessment of Cancer Therapy—Lymphedema (FACT-B+4), and Breast Cancer Treatment Outcomes Scale (BCTOS).Main Outcomes and MeasuresChanges in PRO measure scores and subscores over time.ResultsAmong 31 patients, the median (IQR) age was 61 (56-66) years, 26 (84%) were White, and 26 (84%) were non-Hispanic. A total of 15 (48%) had triple-negative disease and 16 (52%) had ERBB2-positive disease. Decisional comfort was high at baseline (median [IQR] DRS score 10 [0-25] on a 0-100 scale, with higher scores indicating higher decisional regret) and significantly increased over time (median [IQR] DRS score at 36 months, 0 [0-20]; P < .001). HRQOL was relatively high at baseline (median [IQR] FACT-B composite score 121 [111-134] on a 0-148 scale, with higher scores indicating higher HRQOL) and significantly increased over time (median [IQR] FACT-B score at 36 months, 128 [116-137]; P = .04). Perceived differences between the affected breast and contralateral breast were minimal at baseline (median [IQR] BCTOS score 1.05 [1.00-1.23] on a 1-4 scale, with higher scores indicating greater differences) and increased significantly over time (median [IQR] BCTOS score at 36 months, 1.36 [1.18-1.64]; P < .001). At 36 months postradiotherapy, the cosmetic subscore was 0.45 points higher than baseline (95% CI, 0.16-0.74; P = .001), whereas function, pain, and edema subscores were not significantly different than baseline.Conclusions and RelevanceIn this nonrandomized phase 2 clinical trial, analysis of PROs demonstrated an overall positive experience for trial participants, with longitudinal improvements in decisional comfort and overall HRQOL over time and minimal lasting adverse effects of therapy.Trial RegistrationClinicalTrials.gov Identifier: NCT02945579

PURPOSE Breast-conserving therapy (BCT) is the preferred treatment for unifocal breast cancer (BC). The oncologic safety of BCT for multiple ipsilateral breast cancer (MIBC) has not been demonstrated in a prospective study. ACOSOG Z11102 (Alliance) is a phase II, single-arm, prospective trial designed to evaluate oncologic outcomes in patients undergoing BCT for MIBC. PATIENTS AND METHODS Women age 40 years and older with two to three foci of biopsy-proven cN0-1 BC were eligible. Patients underwent lumpectomies with negative margins followed by whole breast radiation with boost to all lumpectomy beds. The primary end point was cumulative incidence of local recurrence (LR) at 5 years with an a priori rate of clinical acceptability of <8%. RESULTS Among 270 women enrolled between November 2012 and August 2016, there were 204 eligible patients who underwent protocol-directed BCT. The median age was 61 years (range, 40-87 years). At a median follow-up of 66.4 months (range, 1.3-90.6 months), six patients developed LR for an estimated 5-year cumulative incidence of LR of 3.1% (95% CI, 1.3 to 6.4). Patient age, number of sites of preoperative biopsy–proven BC, estrogen receptor status and human epidermal growth factor receptor 2 status, and pathologic T and N categories were not associated with LR risk. Exploratory analysis showed that the 5-year LR rate in patients without preoperative magnetic resonance imaging (MRI; n = 15) was 22.6% compared with 1.7% in patients with a preoperative MRI (n = 189; P = .002). CONCLUSION The Z11102 clinical trial demonstrates that breast-conserving surgery with adjuvant radiation that includes lumpectomy site boosts yields an acceptably low 5-year LR rate for MIBC. This evidence supports BCT as a reasonable surgical option for women with two to three ipsilateral foci, particularly among patients with disease evaluated with preoperative breast MRI.

Abstract Background Breast conserving therapy (BCT) is accepted as a preferred option for unifocal breast cancer. However, the oncologic safety of BCT for multiple ipsilateral breast cancer (MIBC), has not been demonstrated in a prospective study. The ACOSOG (Alliance) Z11102 phase II single arm prospective trial was designed to evaluate outcomes with BCT for MIBC. Methods Women age 40+ with 2 or 3 foci of biopsy proven breast cancer (BC) (each site &lt; 5cm in size with at least 1 site invasive) separated by &gt;2-3 cm of normal breast tissue and disease limited to two quadrants of the breast with cN0 or cN1 disease were eligible. All patients had pre-operative mammogram and breast MRI was initially required and subsequently made optional. Neoadjuvant therapy was not allowed. Patients were treated with lumpectomy resected to negative margins followed by whole breast radiation with boost to all lumpectomy beds. The primary endpoint of Z11102 is the cumulative incidence of local recurrence (LR, defined as histologic evidence of ductal carcinoma in situ or invasive BC in the ipsilateral breast or chest wall) at 5 years (treating death and distant and nodal/regional recurrence as competing risks) to assess whether the rate is greater than 8%. Data were frozen 5/25/2022. Results From 11/2012-8/2016, 270 women were enrolled. Of these, 33 were ineligible, 14 converted to mastectomy, 11 were unable to meet protocol-specific radiation endpoints, 1 had no definable tumor, 1 had 4 sites of cancer and 16 withdrew before completing surgery and radiation, leaving 194 patients [median age 61 (range 40-87)] eligible who completed breast conserving surgery and radiation therapy. With median follow-up of alive patients of 66.6 months (range: 4.1, 90.6), 6 patients have developed LR (5 ipsilateral breast and 1 chest wall), corresponding to an estimated cumulative incidence of local recurrence of 3.2% (95% CI: 1.3, 6.4) at 5 years. No patients have developed regional recurrence, 5 patients developed distant recurrence, 0 patients developed local and distant recurrence, 5 patients developed contralateral BC, 3 new non-BC primaries and 8 patients have died (1 related to BC). The rate of local recurrence in patients without a breast pre-op MRI (n=14) was 22.6% at 5 years compared to 1.7% among the 180 patients with a preop MRI (p=0.002). Patient age, number of sites of preoperative biopsy proven BC, HER2 status, pathologic T and N category were not statistically significantly associated with risk of LR. Conclusion The Z11102 clinical trial demonstrates that for women with MIBC breast conserving surgery with adjuvant radiation with lumpectomy site boosts has an acceptably low LR rate (3.2% at 5 years), making this a reasonable consideration for women with 2-3 ipsilateral foci. The LR rate was significantly higher in the small cohort of patients without preoperative breast MRI. Support: U10CA180821, U10CA180882; https://acknowledgments.alliancefound.org. ClinicalTrials.gov Identifier: NCT01556243 Table 1: Factors associated with LR after BCT for MIBC Citation Format: Judy C. Boughey, Kari M. Rosenkranz, Karla V. Ballman, Linda McCall, Bruce G. Haffty, Laurie W. Cuttino, Charlotte D. Kubicky, H. T. Carisa Le-Petross, Kimberly Van Zee, Armando E. Giuliano, Olwen M. Hahn, Kelly K. Hunt, Lisa Carey, Ann Partridge. Impact of Breast Conservation Therapy on Local Recurrence in Patients with Multiple Ipsilateral Breast Cancer – Results from ACOSOG Z11102 (Alliance) [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 GS4-01.

Abstract Purpose: To evaluate prediction of response and event-free survival (EFS) following neoadjuvant endocrine therapy by SET2,3 index of nonproliferation gene expression related to estrogen and progesterone receptors adjusted for baseline prognosis. Experimental Design: A correlative study was conducted of SET2,3 measured from gene expression profiles of diagnostic tumor (Agilent microarrays) in 379 women with cStage II–III breast cancer from the American College of Surgeons Oncology Group Z1031 neoadjuvant aromatase inhibitor trial SET2,3 was dichotomized using the previously published cutoff. Fisher exact test was used to assess the association between SET2,3 and low proliferation at week 2–4 [Ki67 ≤ 10% or complete cell-cycle arrest (CCCA; Ki67 ≤ 2.7%)] and PEPI-0 rate in cohort B, and the association between SET2,3 and ypStage 0/I in all patients. Cox models were used to assess EFS with respect to SET2,3 excluding cohort B patients who switched to chemotherapy. Results: Patients with high SET2,3 had higher rate of pharmacodynamic response than patients with low SET2,3 (Ki67 ≤ 10% in 88.2% vs. 56.9%, P &lt; 0.0001; CCCA in 50.0% vs. 26.2%, P = 0.0054), but rate of ypStage 0/I (24.0% vs. 20.4%, P = 0.4580) or PEPI = 0 (28.4% vs. 20.6%, P = 0.3419) was not different. Patients with high SET2,3 had longer EFS than patients with low SET2,3 (HR, 0.52, 95% confidence interval: 0.34–0.80; P = 0.0026). Conclusions: This exploratory analysis of Z1031 data demonstrated a higher rate of pharmacodynamic suppression of proliferation and longer EFS in high SET2,3 disease relative to low SET2,3 disease. The ypStage 0/I rate and PEPI = 0 rate were similar with respect to SET2,3.

Abstract Background: There is debate regarding the benefit of breast surgery in women with stage IV breast cancer, especially among those with oligometastatic disease and good response to systemic therapy. Although some retrospective studies have suggested that locoregional therapy may improve survival, this finding has not been universally replicated in randomized controlled trials (RCT) in India, Turkey, and recently the US. To assess need for dissemination of trial results by members of the Alliance/American College of Surgeons Clinical Research Program Dissemination and Implementation (ACS CRP D&I) committee, we sought to determine trends in surgical resection and other therapies for stage IV breast cancer in response to these findings. Methods: The National Cancer Database (NCDB) was queried to identify women diagnosed with clinical stage IV breast cancer of ductal, lobular, or metaplastic histology between 2004-2017. Trends in the rate of women who underwent surgery with breast-conserving surgery (BCS) or mastectomy, radiation, and/or systemic treatments were compared. Possible predictors of breast surgery were examined in univariable and multivariable analysis. Results: We identified 87,331 cases meeting inclusion criteria and assessed demographics for surgery versus no surgery. Of the 87,331 cases, 7,718 (9%) underwent BCS and 17,625 (20%) underwent mastectomy. Rates of breast surgical resection for women with clinically diagnosed stage IV breast cancer rose until 2009, reaching a peak at 37%, followed by a decline to a rate of 18% in 2017 (Table). The largest decline was seen in the hormone receptor positive (HR+) and HER2- subgroup with 71% of patients undergoing surgery in 2007 down to 15% in 2017. Concurrently, the mean number of days between chemotherapy initiation and definitive surgery has been on the rise, ranging from 52 days in 2004 up to 94 days in 2017. In 2004, the rate of systemic therapy alone was slightly more common than locoregional therapy (surgery and/or radiation) with or without systemic therapy (48% vs 37%). By 2017, systemic therapy alone was by far more frequently utilized (69% vs 20%, p&lt;0.001). On multivariable analysis, factors associated with reduced odds of receiving surgery were older age, black race, higher comorbidity index, being uninsured, smaller tumors, lower histologic grade, multiple sites of metastasis, and treatment with chemo-endocrine therapy (all group p values ≤0.001). Factors associated with increased odds of receiving surgery were metaplastic histology, TN subtype, and radiation therapy (all group p values ≤0.001). Conclusions: Rates of surgical resection of the breast primary for stage IV breast cancer have been on the decline in recent years, especially for HR+/HER2- disease, suggesting that providers are responding to the lack of benefit demonstrated in RCTs. Higher rates of surgery in patients with HR-/HER2+ disease and the concurrent rise in the time interval between initiation of systemic therapy and definitive surgical intervention suggest that providers may still be selecting surgery for patients with certain subtypes or those with a durable response to systemic therapy. These areas of continued clinical equipoise could be a target for future studies or de-implementation strategies. OverallHR+/HER2-HER2+TNUnknownSurgery/Total%Surgery/Total%Surgery/Total%Surgery/Total%Surgery/Total%20041189/351334-55-30-50-3420051202/353834-65-35-23-3420061268/375834-54-36-31-3420071571/433636-71-41-32-3620081992/54203754/925926/544820/41491892/52333620092194/592437172/3604883/1525556/106531883/53063520102318/6419361162/331835554/134841352/80144250/9522620112322/6921341220/378932532/144137384/91542186/7762420122238/7110311177/393830587/163536339/85340135/6842020132147/7579281173/423128534/172831334/92536106/6951520142013/8033251086/442825496/185227306/99831125/7551720151805/794323914/434321517/198126288/9962986/6231420161609/819420829/464018459/196823247/10122474/5741320171477/813618722/467815421/190522256/10372578/51615Percent of women with stage IV breast cancer undergoing surgery by year and receptor subtype. Rows containing any number &lt;10 are not reported by subtype to maintain confidentiality, per NCDB guidelines. Citation Format: Sasha R Douglas, Ingrid Lizarraga, Judy C Boughey, Anna Weiss, Kelly Hunt, Diana Dickson-Witmer, Preeti D Subhedar, Ko Un Park, Beiqun Zhao, Sarah Blair. Trends in surgical resection for stage IV breast cancer: Less surgery more systemic treatment [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 PD7-06.

Abstract Background: Neoadjuvant ET (NET) offers an opportunity to assess ET sensitivity for ER+ HER2- BC and potentially to tailor therapy. Ki67 &gt;10% on biopsy after 2-4 weeks (wks) of NET identifies patients (pts) with intrinsic ET resistance; while pathologic complete response (pCR) and modified preoperative endocrine prognostic index of 0 (mPEPI 0: pT1-2N0, Ki67 ≤2.7%) at surgery indicates sensitivity to ET. However, on-NET biopsy is not always acceptable or feasible and delays the ET sensitivity determination. PAM50 ROR score and intrinsic subtypes by tumor RNA profiling are prognostic in pts with early stage ER+ HER2- BC, and predict pCR rates to neoadjuvant chemotherapy (NCT) (PMC2667820). We therefore hypothesized that PAM50 analysis on pre-NET biopsies could predict the likelihood of a) a high on-NET Ki67, b) mPEPI-0 or pCR at surgery and, c) pCR for pts triaged to NCT. Methods: The ALTERNATE trial is a phase III study that randomized postmenopausal pts with clinical stage II/III ER+ (Allred score 6-8) HER2- BC to receive neoadjuvant anastrozole, fulvestrant, or both for 6 months before surgery. Research biopsy was required at pre-NET and wk 4, then optional at wk 12. Pts with Ki67 &gt;10% on biopsy at wk 4 or 12 discontinued NET and were offered NCT. PAM50 intrinsic subtype and ROR-P values were generated from mRNA sequencing (RNASeq) analysis on pre-NET biopsies using open-source informatics (PMC7723687) and evaluated for prediction of on-NET Ki67 &gt;10% at wk 4 or 12, pCR or mPEPI-0 post NET, and pCR post NCT. Results: 749 of 1,297 eligible trial pts were included in the analyses, after excluding 548 pts due to insufficient pre-NET tumor for RNASeq (n=511) or PAM50 normal subtype (n=37). Similar to the entire ALTERNATE population, the rate of Ki67 &gt;10% at wk 4 or 12 was 24.4% (95% CI: 21.4-27.7%) and the rate of mPEPI-0/pCR post NET was 19.8% (95% CI: 17.0-22.8%). There were 393 (52.5%) Lum A, 302 (40.3%) Lum B, and 54 (7.2%) non-Lum (9 Basal, 45 HER2-E) BCs. These included 196 (26.2%) ROR-P low, 354 (47.3%) ROR-P medium and 199 (26.6%) ROR-P high BCs. Both the rates of Ki67 &gt;10% at wk 4 or 12 and mPEPI-0/pCR differed significantly with respect to PAM50 subtype or ROR-P category, such that Lum A or ROR-P low BCs were least likely to have a Ki67 &gt;10% at wk 4 or 12 and most likely to achieve mPEPI-0/pCR (Table). 93 of 168 (55.4%) pts triaged to NCT had RNA-seq results, yielding 26 Lum A, 49 Lum B, 4 Basal and 14 HER2-E, with the pCR rates of 0%, 6.1%, 0%, and 21.4%, respectively. There were 10 ROR-P low, 39 medium, and 44 high tumors, with a pCR rate of 0%, 5.1% and 9.1%, respectively. Conclusion: These data indicate that both baseline ROR-P and intrinsic subtype are predictive of early on-NET Ki67 &gt; 10% and mPEPI 0/pCR at surgery after NET. For pts triaged to NCT based on an early on-NET Ki67 &gt;10%, the HER2-E group had the highest pCR rate (20%) and no pCRs were observed in Lum A. These data may be useful for directing neoadjuvant therapy in postmenopausal pts with ER+ HER2- BC. Support: U10CA180821, U10CA180882, U24CA196171, UG1CA189856, U10CA180868 (NRG), NCI BIQSFP, BCRF, Genentech, AstraZeneca. https://acknowledgments.alliancefound.org. (MJE) CPRIT RR140033, P50CA186784, P50-CA58223, U01 CA214125, U24CA210954, Gift from Ralph and Lisa Eads, McNair Scholarship. Trials.gov Identifier: NCT01953588. Table 1.Rates of Ki67 &gt;10% and mPEPI-0/pCR post NET by PAM50 subtype and ROR-P categoryKi67 &gt;10% at wk 4 or 12mPEPI 0/pCR post NETPAM50 SubtypenYes, n (%)PnNo, n (%)PLum A37251 (13.7%) 95% CI: 10.4-17.6%&lt;0.0001393104 (26.5%) 95%CI: 22.2-31.1%&lt;0.0001Lum B29394 (32.1%) 95% CI: 26.8-37.8%30243 (14.2%) 95%CI: 10.5-18.7%Non-luminal (Basal and HER2-E)5338 (71.7%) 95%CI: 57.6-83.2%541 (1.9%) 95%CI: 0.05-9.9%ROR-P CategorynYes, n (%)PnNo, n (%)PLow18018 (10.0%) 95%CI: 6.0-15.3%&lt;0.000119660 (30.6%) 95%CI: 24.2-37.6%&lt;0.0001Intermediate34474 (21.5%) 95%CI: 17.3-26.2%35471 (20.1%) 95%CI: 16.0-24.6%High19491 (46.9%) 95%CI: 39.7-54.2%19917 (8.5%) 95%CI: 5.1-13.3% Citation Format: Cynthia X Ma, Meenakshi Anurag, Travis Dockter, Jeremy Hoog, Aranzazu Fernandez-Martinez, Cheng Fan, Richard Gibbs, Souzan Sanati, Kiran Vij, Mark Watson, Olwen Hahn, Joseph Guenther, Abigail Caudle, Erika Crouch, Amy Tiersten, Monica Mita, Wajeeha Razaq, Tina J Hieken, Yang Wang, A. Marilyn Leitch, Gary W Unzeitig, Anna Weiss, Eric P Winer, Kelly Hunt, Ann H Partridge, Lisa A Carey, Charles M Perou, Matthew J Ellis, Vera Suman. Pam50 intrinsic subtype and risk of recurrence score (ROR) for the prediction of endocrine (ET) sensitivity and pathologic response to chemotherapy in postmenopausal women with clinical stage II/III estrogen receptor positive (ER+) and HER2 negative (HER2-) breast cancer (BC) in the alternate trial (Alliance A011106) [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 PD9-03.