Endocrine-Sensitive Disease Rate in Postmenopausal Patients With Estrogen Receptor-Rich/ERBB2-Negative Breast Cancer Receiving Neoadjuvant Anastrozole, Fulvestrant, or Their Combination: A Phase 3 Randomized Clinical Trial

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.

Abstract CT026: The effect of intrinsic subtype on inhibition of tumor growth by anastrozole vs. fulvestrant vs. the combination: Results from the Alliance neoadjuvant endocrine therapy (NET) ALTERNATE trial

Introduction: The ALTERNATE trial randomized postmenopausal women with ER Allred 6-8 HER2- breast cancer to 6 months of NET with anastrozole (A), fulvestrant (F) or the combination (A+F). Biopsies were taken preNET and after 4-weeks(wks). Patients with Ki67 values &gt;10% at 4-wks were offered triage to neoadjuvant chemotherapy. Patients with on-treatment Ki67 ≤ 10% who completed NET underwent surgery and Ki67 was reassessed. The primary endpoint was endocrine-sensitive disease rate (ESDR). ESD is defined as pCR or PEPI-0 residual disease (pT1-2, pN0, Ki67 ≤ 2.7%). We previously reported that the ESDR difference between the F-containing arms and the A arm was not &gt;10% (ASCO 2020) and that baseline RNA-seq-based intrinsic subtypes predicted outcomes overall (SABCS 2021). Herein we describe relationships between PAM50 intrinsic subtype and Ki67 values by treatment arm because comparative drug effectiveness in adjuvant endocrine therapy studies in ER+ HER2- breast cancer can be predicted by the degree of Ki67 suppression (PMC3518447).

Methods: 743 of the 1297 eligible patients (A: 264; F: 231; A+F: 248) had RNA extracted from preNET frozen tumor biopsies with &gt;50% tumor content and subjected to RNA seq. Intrinsic subtypes were then assigned as LumA, LumB, and NonLum (Basal or HER2-E) using open-source PAM50-based informatics. Differences in the proportion with wk4 Ki67 &gt; 10%, % change in wk4 ki67, and surgical CCCA (Ki67 ≤ 2.7%) rate (sxCCCA) between treatments and by intrinsic subtype was assessed using stratified logistic regression, Wilcoxon rank sum test, and Fisher’s exact test, respectively. Analysis of sxCCCA excluded those who failed to complete NET for reasons other than disease progression or early Ki67 &gt;10%.

Results: Amongst the 358 LumA cases there were no significant differences in Ki67-based endpoints between treatments. Among the 292 LumB cases, the wk4 ki67 &gt; 10% rate was lower with A+F (19.4%) than A (43%) (P=0.0002) and was somewhat lower in F (31%) versus A (P=0.076). The % change in wk4 Ki67 in LumB cases, adjusted for baseline Ki67, showed markedly superior suppression for A+F versus A (-90% vs. -77%; P=&lt;0.0001) and versus F (-90% vs. -80%; P=0.0026). Furthermore sxCCCA rates were significantly higher with A+F than A (53% vs. 25% P = &lt;0.0001) and somewhat higher for F (37%) than A (p=0.068), indicating that superior antiproliferative effects for A+F persist after 6 months on therapy. Lack of Ki67 suppression in response to treatment was observed in the majority of 43 NonLum samples regardless of treatment.

Conclusion: The combination of A+F was significantly more effective than either drug alone for the control of LumB breast cancer cell proliferation. This suggests that A+F may be a more effective adjuvant endocrine therapy than A alone in LumB disease. The lower Ki67 suppression with A alone also suggests that poorer outcome in some LumB tumors may be due to insufficient ER targeting rather than ER-independent tumor growth

Support: U10CA180821, U10CA180882, U24CA196171, UG1CA189856, U10CA180868 (NRG), NCI BIQSFP, BCRF, Genentech, AstraZeneca. https://acknowledgments.alliancefound.org. (MJE) CPRIT RR140033, P50-CA186784, P50-CA58223, U01-CA214125, U24-CA210954, Gift from Ralph and Lisa Eads, McNair Scholarship.

ClinicalTrials.gov Identifier: NCT01953588

Citation Format: Matthew J. Ellis, Meenakshi Anurag, Jeremy Hoog, Aranzazu Fernandez-Martinez, Cheng Fan, Richard Gibbs, Souzan Sanati, Kiran Vij, Mark Watson, Travis Dockter, Olwen Hahn, Joseph Guenther, Abigail Caudle, Erica Crouch, Amy Tiersten, Monica Mita, Wajeeha Razaq, Tina J. Hieken, Yang Wang, A. Marilyn Leitch, Gary W. Unzeitig, Eric Winer, Anna Weiss, Kelly Hunt, Ann H. Partridge, Charles M. Perou, Vera Suman, Cynthia X. Ma, Lisa A. Carey. The effect of intrinsic subtype on inhibition of tumor growth by anastrozole vs. fulvestrant vs. the combination: Results from the Alliance neoadjuvant endocrine therapy (NET) ALTERNATE trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT026.

Abstract 2214: Disparity in the uptake of risk-reducing surgery after GCRA in Hispanic patients in Latin America and in the United States

Background: Patients at increased risk of breast (BC) and/or ovarian (OC) cancer can opt for risk-reducing surgeries (RRS). However, there are disparities in access to genomic cancer risk assessment (GCRA) and cancer prevention interventions related to geography, socioeconomic status, and limited public health support. We studied factors that affect the uptake of risk-reducing mastectomy (RRM) and salpingo-oophorectomy (RRSO) in Hispanic patients of Latin America (LatAm) and the United States (US).

Methods: Hispanic women enrolled in the Clinical Cancer Genomics Community Research Network registry between 1997-2019 who underwent genetic testing, had a personal or family history (FHX) of BC or OC, and had ≥6 months of follow-up data were considered eligible. Demographic and clinical factors associated with risk-appropriate uptake of RRS were considered. Data were analyzed using Fisher’s exact tests and logistic regression models.

Results: 1818 patients with a median follow-up of 43 months were studied. Most were from the US (65%), followed by Mexico (21%), Peru (10%), Colombia (2%), and Puerto Rico (2%). Median age at enrollment was 44 years; 81% had a personal history of BC and 5% of OC. Cancer-associated pathogenic variants (PVs) were identified in 459 patients (25%); 409 were in BRCA, 36 had other BC-susceptibility PVs (ATM, CHEK2, PALB2, PTEN, or TP53), and 14 had other OC-susceptibility PVs (BRIP1, MSH2, MSH6, MLH1, or RAD51C). Overall, 449/1715 (26.2%) patients underwent RRM, with a higher rate among patients in the US than those in LatAm (31% vs. 17%, p&lt;0.01); 377/1517 (25%) patients underwent RRSO, with no regional differences observed (24% vs. 27%, p=0.22). The factors associated with undergoing RRM were US residence (OR 2.2; 95% CI 1.7-2.8), age ≤50 (OR 2.2; 95% CI 1.7-2.8), carrying a BC-predisposing PV (OR 3.5; 95% CI 2.8-4.4), positive FHX for BC (OR 1.5; 95% CI 1.2-1.9), and personal history of cancer (OR 3.6; 95% CI 2.4-5.6). In a multivariate model, US residence, age, and previous BC diagnosis remained independent predictors for RRM in BC-susceptibility gene PV carriers, while age was not a significant factor in non-carriers. The factors associated with undergoing RRSO included being a carrier of an OC-predisposing PV (OR 6.3; 95% CI 4.8-8.1), positive FHX for OC (OR 2.1; 95% CI 1.5-2.8), and previous cancer diagnosis (OR 1.7; 95% CI 1.2-2.5). In carriers of OC-susceptibility gene PVs, residing in US and previous cancer diagnosis were independently associated with RRSO, while positive FHX for OC and previous cancer diagnosis were identified as independent factors in non-carriers.

Conclusion: There are disparities in the uptake of RRS outside the US. Beyond limitations in resources, understanding the factors associated with undergoing RRS could be key to developing targeted interventions to improve the uptake of risk-appropriate measures in hereditary cancer syndrome patients.

Citation Format: Jeffrey N. Weitzel, Yanin Chavarri-Guerra, Ana Ferrigno, Pamela Mora-Alférez, Annette Campbell-Fontaine, Cynthia Villarreal-Garza, Alejandro Mohar-Betancourt, Gubidxa Gutierrez-Seymour, Gary W. Unzeitig, Sandra Brown, Bita Nehoray, Azucena del Toro-Valero, Pamela Ganschow, Ian Komenaka, Yenni Rodriguez, Francisco Gutierrez-Delgado, Kathleen R. Blazer. Disparity in the uptake of risk-reducing surgery after GCRA in Hispanic patients in Latin America and in the United States [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2214.

Abstract PD9-03: 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)

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.

The Influence of Vitamin D on Mammographic Density: Results from CALGB 70806 (Alliance) a Randomized Clinical Trial

Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and toxicity limits use of these agents. Vitamin D is a potential prevention therapy for both ER+ and ER- disease and is safe with few side effects. This study evaluates the effect of 1-year of vitamin D supplementation on mammographic density (MD), a biomarker of breast cancer risk in a multicenter randomized controlled trial. Premenopausal women with ≥25% MD and no history of cancer were randomly assigned to 2,000 international units (IU) of vitamin D or placebo orally daily for 1 year. Change in percent MD was evaluated using Cumulus software after all participants completed treatment. Three hundred women enrolled between January 2011 and December 2013 with a mean age of 43 and diverse ethnicity [14% Hispanic, 12% African American (AA)]. Supplementation significantly increased vitamin D levels compared with placebo (14.5 ng/mL vs. -1.6 ng/mL; P < 0.0001) with all participants on the vitamin D arm achieving vitamin D sufficiency at 12 months. Vitamin D was safe and well tolerated. After adjustment for baseline MD, the mean between-arm difference (vitamin D vs. placebo) at 1 year was -0.75 (-0.26, 1.76; P = 0.56). A greater effect was seen for women with ≥50% MD and AA women, although neither reached significance. This randomized controlled trial demonstrated significant improvement in vitamin D levels with 2,000 IU for 1 year, with 100% of supplemented women achieving sufficiency. However, a null effect was seen regarding change in MD for premenopausal women (the primary outcome of the study). PREVENTION RELEVANCE: Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and are underutilized due to toxicity and side effects. Vitamin D is a potential prevention therapy for both ER+ and ER- disease and is safe with few side effects.

Abstract GS4-05: Neoadjuvant chemotherapy (NCT) response in postmenopausal women with clinical stage II or III estrogen receptor positive (ER+) and HER2 negative (HER2-) breast cancer (BC) resistant to endocrine therapy (ET) in the ALTERNATE trial (Alliance A011106)

Background: Ki67 values &gt;10% 2-4 weeks (wks) after starting neoadjuvant ET (NET) indicates persistent cell proliferation, resistance to ET, and is associated with increased risk of recurrence. The ACOSOG Z1031 trial suggested that these tumors are also relatively chemotherapy (chemo) resistant with a low pathologic complete response (pCR) rate to NCT. The ALTERNATE trial (NCT01953588) is a randomized study of neoadjuvant anastrozole (ANA), fulvestrant (FUL), or ANA + FUL in postmenopausal patients (pt) with newly diagnosed clinical stage II or III ER+ (Allred score 6-8)/HER2- BC. Ki67 &gt;10% at wk 4 or 12 after starting NET triggered triage to NCT of physician choice or weekly paclitaxel. Pts who refused protocol-directed therapy, were not candidates for NCT, or decided to undergo immediate surgery are being followed per protocol. Here we report the rates of pCR and residual cancer burden (RCB) following NCT for pts triaged to NCT due to Ki67 &gt;10% at wk 4 or 12. Results: Of the 1,299 eligible pts randomized to receive ANA, FUL, or ANA + FUL, 286 (22%) had Ki67 &gt;10% at wk 4 or 12. 168 of these 286 pts (58.7%) chose to switch to NCT, 32 went to surgery (11.2%), and 86 discontinued further protocol-directed therapy (30.1%). Among the 168 pts who underwent NCT, the presenting clinical T stages were cT2 (n=113; 67.26%), cT3 (n=47; 27.98%) and cT4 (n=8; 4.76%) and N stages were cN0 (n=82; 48.8%), cN1 (n=75; 44.6%), cN2/3 (n=9; 5.4%) and cNx (n=2; 1.2%). Central ER testing was performed on pre-treatment biopsies and confirmed ER Allred score 6-8 in 155 of 168 (92.2%) pts, with the rest being ER Allred score 4-5 (n=5; 3%), ER- (Allred score 0) (n=2; 1.2%), or not tested (n=6; 3.6%). Most (n=139; 82.7%) were ER+/PR+, while 17.3% (n=29) were ER+/PR-, and tumor grades were G1 (n=10; 6%), G2 (n=99; 58.9%), G3 (n=54; 32.1%), not reported (n=5; 3%). Baseline Ki67 levels prior to NET were &gt;10% in 94% (n=158), ≤10% in 3% (n=5), and not done in 3% (n=5). NCT regimens administered included doxorubicin/cyclophosphamide (AC) followed by paclitaxel (T) (n=60; 35.71%); weekly paclitaxel (n=56; 33.33%), docetaxel/cyclophosphamide (TC) (n=33; 19.65%), other doxorubicin and/or taxane containing regimen (n=17; 10.12%), and cyclophosphamide/methotrexate/fluorouracil (CMF) (n=2; 1.19%). 35 (20.8%) pts did not complete planned course of NCT due to toxicity (n=27) or refusal (n=8). 154 NCT pts underwent surgery (mastectomy in 40.3%, and breast conserving surgery in 59.7%). The path ypT stages were Tis/0 (n=10; 6.5%), T1 (n=62; 40.3%), T2 (n=61; 39.6%), and T3/4 (n=21; 13.6%), and the ypN stages were N0 (n=66; 42.9%), N1 (n=57; 37%), N2/3 (n=30; 19.5%), and Nx (n=1; 0.6%). Among the 168 pts who started on NCT (intent to treat population), there were 8 pCRs (no invasive disease in the breast or lymph nodes) (4.8%; 95% CI: 2.1% to 9.2%). Residual Cancer Burden (RCB) categories include RCB 0 (n=8; 4.8%), RCB 1 (n=15; 8.9%), RCB 2 (n=82; 48.8%), RCB 3 (n=42; 25.0%), and not determined (n=21; 12.5%). Correlations of baseline pt and tumor characteristics with pathology response to NCT will also be presented. Conclusion: In pts with NET-resistant ER+/HER2- BC, salvage NCT is not likely to induce a complete or near complete response. More effective treatments are needed for this high-risk ER+/HER2- pt population. Support: U10CA180821, U10CA180882, U24CA196171, UG1CA189856, U10CA180868 (NRG); NCI BIQSFP, BCRF, Genentech, AstraZeneca. https://acknowledgments.alliancefound.org. Clinical Trials.gov Identifier: NCT01953588

Citation Format: Cynthia X Ma, Vera Suman, A. Marilyn Leitch, Souzan Sanati, Kiran Vij, Gary W Unzeitig, Jeremy Hoog, Mark Watson, Olwen Hahn, Joseph Guenther, Abigail Caudle, Erika Crouch, Horacio Maluf, Amy Tiersten, Monica Mita, Wajeeha Razaq, Tina J Hieken, Yang Wang, Travis Dockter, Jo Anne Zujewski, Anna Weiss, Kelly Hunt, Clifford Hudis, Eric P Winer, Matthew J Ellis, Lisa A Carey, Ann H Partridge. Neoadjuvant chemotherapy (NCT) response in postmenopausal women with clinical stage II or III estrogen receptor positive (ER+) and HER2 negative (HER2-) breast cancer (BC) resistant to endocrine therapy (ET) in the ALTERNATE trial (Alliance A011106) [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 GS4-05.

Abstract PD2-10: Validation of a predictive model for potential response to neoadjuvant endocrine therapy (NET) in postmenopausal women with clinical stage II or III estrogen receptor positive (ER+) and HER2 negative (HER2-) breast cancer (BC): An ALTERNATE trial analysis (Alliance A011106)

Background: NET is offered to postmenopausal patients (pts) with clinical stage 2/3 ER+/HER2- BC to promote breast-conserving surgery. Also limited surgical accessibility during the COVID19 pandemic has increased NET utility. Inability to identify ET-resistant disease at diagnosis risks disease progression (PD) and delays more effective treatments. Dowsett et al. recently demonstrated that baseline levels of ER, progesterone receptor (PR), Ki67 (&gt;15% vs ≤15%), and Ki67 (&gt;10% vs ≤10%) 2-4 weeks (wks) after starting NET may improve appropriate patient (pt) selection for NET (PMC7280290). The ER, PR and Ki67-based prediction model divides pts with primary ER+/HER2- BC into 3 groups for appropriateness for NET: (Group 1) NET is likely to be inappropriate (Allred ER &lt;6 or ER 6 and PgR &lt;6), (Group 2) NET may be appropriate and a biopsy for on-treatment Ki67 analysis may be considered after 2-4 wks of NET (2A: ER 7 or 8 and PgR &lt;6 and 2B: ER 6 or 7 and PgR ≥6) given that on-treatment Ki67 &gt;10% has been associated with worse outcome (PMC5455353), or (Group 3) NET is appropriate (ER 8 and PgR ≥6). The ALTERNATE trial (NCT01953588) randomized postmenopausal women with clinical stage II or III, ER+ (Allred score 6-8)/HER2- BC to receive anastrozole (ANA), fulvestrant (FUL), or ANA + FUL for 6 months, unless Ki67 was &gt;10% on wk 4 or 12 biopsy, in which case pts were triaged to receive neoadjuvant chemotherapy (NCT) or surgery. As previously reported, the ET-sensitive disease (mPEPI 0 plus pCR) rates were similar across the treatment arms and overall 22% (286 of 1,299) pts had Ki67 &gt;10% at wk 4 or 12. The ALTERNATE trial therefore provides a large independent data set to evaluate the NET appropriateness model.

Results: Among 1,299 eligible pts randomized to receive 6 months of NET, 214 were excluded due to absent HR Allred score (n=41) or absence of pre-treatment and wk 4 Ki67 determinations (n=173). The proportions of the remaining 1,085 pts in Group 1, 2 and 3 were 1% (n=10), 43% (n= 468), and 56% (n=607), respectively. On-study Ki67 &gt;10% prompting conversion from NET to NCT/Surgery occurred in: Group 1 90% (9 of 10), Group 2 30% (141 of 468), and Group 3 17% (104 of 607) (Table 1). Among the 1,075 pts in Groups 2 and 3, 260 (24%) pts had Ki67 ≤15% at baseline (BL), among whom only 14 (5.4%) had Ki67 &gt;10% at wk 4, compared to 231 of the 815 (28.3%) who had BL Ki67 &gt;15% and subsequent Ki67 &gt;10% at wk 4. 2% of pts who remained on NET due to on-treatment Ki67 &lt;10% had PD. Response and PEPI-0 rates by group will be reported.

Conclusion: ALTERNATE trial data support a model whereby levels of ER, PR and Ki67 at diagnosis can be used for the identification of postmenopausal pts with primary ER+/HER2- BC who are appropriate for NET. When baseline ER Allred scores are &gt;6 and Ki67 ≤15%, there is a low likelihood of ET-resistant disease. When BL Ki67 is &gt;15%, ET sensitivity is variable, and on-treatment biopsy for Ki67 may assist in triaging regarding NET appropriateness, particularly given the extremely low local PD rates seen in ALTERNATE when on-treatment Ki67 was &lt;10%. Support: U10CA180821, U10CA180882, U24CA196171, UG1CA189856, U10CA180868 (NRG); NCI BIQSFP, BCRF, Genentech, AstraZeneca. https://acknowledgments.alliancefound.org; Clinical Trials.gov Identifier: NCT01953588

Table 1 Baseline levels of ER, PR, and Ki67 in Relation to Wk 4 Ki67 (N=1,085)BaselineWeek 4GroupNERAllred ScorePRAllred ScoreKi67Ki67 ≤10%N (%)Ki67 &gt;10%N (%)1N=26&lt;6≤15%0 (0%)2 (100%)9 (90)N=86&lt;6&gt;15%1 (12.5%)7 (87.5%)2AN=647 or 8&lt;6≤15%61 (95.3%)3 (4.7%)90 (30.1)N=2357 or 8&lt;6&gt;15%148 (63%)87 (37%)2BN=466 or 7≥6≤15%42 (91.3%)4 (8.7%)51 (30.2)N=1236 or 7≥6&gt;15%76 (61.8%)47 (38.2%)3N=1508≥6≤15%143 (95.3%)7 (4.7%)104 (17.1)N=4578≥6&gt;15%360 (78.8%)97 (21.2%)

Citation Format: Matthew J Ellis, Vera Suman, A. Marilyn Leitch, Souzan Sanati, Kiran Vij, Gary W Unzeitig, Jeremy Hoog, Mark Watson, Olwen Hahn, Joseph Guenther, Abigail Caudle, Erika Crouch, Horacio Maluf, Mitch Dowsett, Amy Tiersten, Monica Mita, Wajeeha Razaq, Tina J Hieken, Yang Wang, Travis Dockter, Jo Anne Zujewski, Anna Weiss, Clifford Hudis, Eric P Winer, Kelly Hunt, Ann H Partridge, Cynthia X Ma, Lisa A Carey. Validation of a predictive model for potential response to neoadjuvant endocrine therapy (NET) in postmenopausal women with clinical stage II or III estrogen receptor positive (ER+) and HER2 negative (HER2-) breast cancer (BC): An ALTERNATE trial analysis (Alliance A011106) [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 PD2-10.

Disease-Free and Overall Survival Among Patients With Operable HER2-Positive Breast Cancer Treated With Sequential vs Concurrent Chemotherapy: The ACOSOG Z1041 (Alliance) Randomized Clinical Trial

Importance

Pathologic complete response rate (pCR), the primary end point of the ACOSOG (American College of Surgeons Oncology Group) Z1041 (Alliance) trial, and disease-free survival (DFS) and overall survival (OS) in women with operable HER2-positive breast cancer are similar between treatment regimens.

Objective

To assess DFS and OS for patients treated with sequential vs concurrent anthracycline plus trastuzumab.

Design, Setting, and Participants

Phase 3 randomized clinical trial conducted at 36 centers in the continental United States and Puerto Rico. Women 18 years or older with invasive operable HER2-positive breast cancer were enrolled from September 15, 2007, to December 15, 2011, and randomized to 1 of 2 treatment arms. The analysis data set was locked on October 15, 2017, and analysis was completed on December 15, 2017.

Interventions

Patients randomized to arm 1 received 500 mg/m2 of fluorouracil, 75 mg/m2 of epirubicin, and 500 mg/m2 of cyclophosphamide (FEC) every 3 weeks for 12 weeks followed by the combination of 80 mg/m2 of paclitaxel and 2 mg/kg (except initial dose of 4 mg/kg) of trastuzumab weekly for 12 weeks. Patients randomized to arm 2 received the same combination of paclitaxel with trastuzumab weekly for 12 weeks followed by FEC every 3 weeks with weekly trastuzumab for 12 weeks. Women with hormone receptor-positive disease received endocrine therapy, and radiotherapy was delivered at physician discretion.

Main Outcomes and Measures

The primary outcomes were DFS and OS and pCR in the breast and nodes.

Results

Two hundred eighty-two women with HER2-positive breast cancer were enrolled in the trial, and 2 withdrew consent before treatment. Among the remaining 280 women, the median age was 50 years (range, 28-76 years), 232 (82.9%) were white, 29 (10.3%) were black, 8 (2.9%) were Asian, 4 (1.4%) were American Indian or Alaskan Native, and 7 (2.5%) did not report race/ethnicity. There were 22 disease events in arm 1 and 27 in arm 2. Disease-free survival rates did not differ with respect to treatment arm (stratified log-rank P = .96; stratified hazard ratio [HR] [arm 2 to arm 1], 1.02; 95% CI, 0.56-1.83). Overall survival did not differ with respect to treatment arm (stratified log-rank P = .73; stratified HR [arm 2 to arm 1], 1.17; 95% CI, 0.48-2.88).

Conclusions and Relevance

Across a median follow-up of 5.1 years (range, 26 days to 6.2 years), pCR, DFS, and OS did not differ with respect to sequential or concurrent administration of FEC with trastuzumab.

Trial Registration

ClinicalTrials.gov identifier: NCT00513292.

Abstract P5-12-03: Withdrawn

This abstract was withdrawn by the authors.

Effect of Vitamin D Supplementation on Breast Cancer Biomarkers: CALGB 70806 (Alliance) Study Design and Baseline Data

One in eight women will develop breast cancer over their lifetime with 230,000 women diagnosed in 2015. For this reason, breast cancer prevention efforts are essential. Vitamin D, with anticancer properties, may have a role in prevention of some cancers, including breast cancer. This report discusses the rationale, study protocol, and baseline data for a clinical trial of vitamin D and its effects on breast cancer biomarkers. This study was a randomized controlled trial designed to evaluate the effect of a fixed dose of vitamin D on specfic breast cancer biomarkers. Study participants were randomized to take either vitamin D or placebo for a period of 1 year. All participants had mammograms and blood drawn for serum biomarkers. A subset of participants underwent random periareolar fine needle aspiration to draw tissue for biomarkers. From January 2011 to December 2013, 300 premenopausal women, aged 59 or younger, were recruited from 41 institutions across the United States. A total of 102 women underwent random periareolar fine needle aspiration. The last subject completed the trial in January 2015. Baseline vitamin D levels for all participants ranged from 4-72 ng/mL, with 62% of participants being vitamin D deficient at enrollment (≥30 ng/mL or ≥75 nmo-l/L). The mean body mass index was 27.0 kg/m² (range 15.1-53.6 kg/m²). 14% and 11.7% of participants were Hispanic or African American, respectively. Accrual and enrollment of participants is feasible for this type of multi-center prevention trial, and it can readily be carried out in a cooperative group setting.

Abstract 2761: Evaluation of the BOADICEA model for predicting BRCA1 and BRCA2 mutation carrier probabilities in high-risk US Hispanic and Mexican families: A report from the Clinical Cancer Genetics Community Research Network

Background: BRCA1 and BRCA2 (BRCA) mutation prediction models are low cost tools that enable clinicians to target individuals with a higher probability to carry mutations in the BRCA genes. Most of the data used to construct these models were derived from a predominantly non-Hispanic White population. The predictive accuracy of these models in diverse populations is unclear. The Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) was developed using population-based families with multiple affected individuals that were primarily from the UK. The purpose of this study was to investigate and compare the accuracy of BOADICEA for prediction of BRCA mutation status among US Hispanics and a cohort of Mexicans in Guadalajara and Mexico City.

Methods: Hispanic patients undergoing genetic cancer risk assessment (GCRA) were enrolled in an IRB-approved prospective registry from sites within the Clinical Cancer Genetics Community Research Network (CCGCRN), comprised of the City of Hope and 47 collaborating sites representing primarily community-based oncogenetic practices across the US and Latin America, including two cancer institutes in Mexico (University of Guadalajara; Instituto Nacional de Cancerología, Mexico City). Pedigrees were created in Progeny, exported to text files, and then uploaded for probablity calculations according to BOADICEA version 3 guidelines. Accuracy was assessed using an observed versus expected and an area under the receiver operating characteristic (ROC) curve analysis.

Results: Overall, BOADICEA performed better in US Hispanics (area under the curve [AUC] = 0.75) for predicting a BRCA mutation than in the Mexican cohort (AUC = 0.64; p-value = 0.0015). Although BRCA mutations were documented in 238 of 1,247 (19.1%) US Hispanics and 23 of 234 (9.8%) Mexicans, BOADICEA predicted a mean mutation probability of 10.3% and 5.6%, respectively.

Summary: Though generally the best performing model, BOADICEA's ability to predict BRCA mutations has been investigated in previous studies with different populations with varying results. The lower performance of BOADICEA in the Mexican cohort could be a result of the limitations in pedigree data. It's possible that families don't share information about cancer due to cultural norms or fear of stigmitation. It is also possible that the model assumptions about population mutation frequency are inaccurate. The results of this study indicate the need to document the clinical reliability of probability models when evaluating high risk US Hispanics and patients in Mexico.

Citation Format: Jessica Clague, Cynthia Villarreal-Garza, Adrian Daneri Navarro, Alexandra J. Obregon-Tito, Sharon Sand, Tanya A. Chavez, Bita Nehoray, Lacolle Robinson, Lenny Gallardo, Azucena Del Toro, Rosa Alvarez, Kathleen R. Blazer, Blu Yanez, Charité Ricker, Gary W. Unzeitig, Kai Yang, Jeffrey N. Weitzel. Evaluation of the BOADICEA model for predicting BRCA1 and BRCA2 mutation carrier probabilities in high-risk US Hispanic and Mexican families: A report from the Clinical Cancer Genetics Community Research Network. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2761. doi:10.1158/1538-7445.AM2015-2761

Abstract P2-18-07: Nipple sparing mastectomy-infectious complication risk. A preliminary assessment of the American Society of Breast Surgeons nipple sparing mastectomy registry

Objectives: The American Society of Breast Surgeons (ASBS) Nipple Sparing Mastectomy Registry (NSMR) is a prospective, IRB approved, non-randomized, multi-institutional registry assessing surgical techniques, utilized metrics, oncologic outcome, and aesthetic outcome of nipple sparing mastectomies. The registry has been open for enrollment for 26 months. The target accrual is 1000 individuals. This abstract specifically analyzes rates of post-operative infection in NSMs.

Methods: Fifty two investigators from 41 institutions are participating in the ASBS NSMR. A total of 373 patients underwent 631 mastectomies, with indications of prophylaxis (365), cancer (248), and unknown (18). We assessed a sub group of 449 mastectomies, with indications of prophylaxis (253) and cancer (196) that had all data sets completed. We assessed infection rates(characterized as needing oral or iv antibiotics with or without removal of implant/expander and/or debridement) in the entire group as well as by indication (cancer vs. prophylaxis). Factors such as smoking history, previous radiation therapy, previous surgery, incision type, reconstruction technique, and flap dissection technique were analyzed.

Results: In a subgroup of 449 mastectomies (253 prophylactic and 196 cancer):

Post operative infections were reported in 22 (4.9%) of patients: 7 (3.6%) of mastectomies with an indication of cancer and 15 (5.9%) of prophylactic mastectomies (p-value 0.3140). Infections were characterized as: treatment with oral antibiotics alone, treatment with i.v. antibiotics alone, iv antibiotics with washout or debridement, or antibiotics and implant/ tissue expander removal. No correlation was found in smoking history (p-value 1.000), previous breast surgery (p-value 0.1277) or previous radiation (p-value 0.6024). No correlation was found in incision utilized, reconstruction technique, or method of flap dissection either.

Conclusion:

The rate of postoperative infections in nipple sparing mastectomies is comparable if not lower than non-nipple sparing mastectomies. No statistically significant difference in infection rate was found between mastectomies completed for prophylaxis or cancer. No correlation was found between factors such as smoking history, history of radiation therapy, prior breast surgery, incision utilized, reconstruction technique, or method of flap dissection. Improved aesthetics with a nipple sparing approach (technically more demanding and typically through a smaller incision) does not come at the cost of a higher rate of infectious complications.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-18-07.

Randomized phase II neoadjuvant comparison between letrozole, anastrozole, and exemestane for postmenopausal women with estrogen receptor-rich stage 2 to 3 breast cancer: clinical and biomarker outcomes and predictive value of the baseline PAM50-based intrinsic subtype--ACOSOG Z1031

PURPOSE

Preoperative aromatase inhibitor (AI) treatment promotes breast-conserving surgery (BCS) for estrogen receptor (ER)-positive breast cancer. To study this treatment option, responses to three AIs were compared in a randomized phase II neoadjuvant trial designed to select agents for phase III investigations.

PATIENTS AND METHODS

Three hundred seventy-seven postmenopausal women with clinical stage II to III ER-positive (Allred score 6-8) breast cancer were randomly assigned to receive neoadjuvant exemestane, letrozole, or anastrozole. The primary end point was clinical response. Secondary end points included BCS, Ki67 proliferation marker changes, the Preoperative Endocrine Prognostic Index (PEPI), and PAM50-based intrinsic subtype analysis.

RESULTS

On the basis of clinical response rates, letrozole and anastrozole were selected for further investigation; however, no other differences in surgical outcome, PEPI score, or Ki67 suppression were detected. The BCS rate for mastectomy-only patients at presentation was 51%. PAM50 analysis identified AI-unresponsive nonluminal subtypes (human epidermal growth factor receptor 2 enriched or basal-like) in 3.3% of patients. Clinical response and surgical outcomes were similar in luminal A (LumA) versus luminal B tumors; however, a PEPI of 0 (best prognostic group) was highest in the LumA subset (27.1% v 10.7%; P = .004).

CONCLUSION

Neoadjuvant AI treatment markedly improved surgical outcomes. Ki67 and PEPI data demonstrated that the three agents tested are biologically equivalent and therefore likely to have similar adjuvant activities. LumA tumors were more likely to have favorable biomarker characteristics after treatment; however, occasional paradoxical increases in Ki67 (12% of tumors with > 5% increase after therapy) suggest treatment-resistant cells, present in some LumA tumors, can be detected by post-treatment profiling.

Analysis of the prognosis of minimal and occult breast cancers

Of 296 occult breast cancers diagnosed at Kaiser-Permanente Medical Center, Los Angeles, in the last ten years, 80 were classified as minimal and 167 as nonminimal. Minimal cancers were intraductal, lobular in situ, or invasive and 0.5 cm or less in diameter. In the occult-minimal group, no woman had axillary node metastases, and there were no recurrences. In the occult-nonminimal group, 26% of the patients had axillary nodal involvement, with a recurrence rate of 13% and a mortality of 11.6%. Occult breast cancers differed significantly between minimal and nonminimal tumors in both treatment and prognosis. Nonminimal cancers should be treated as any palpable carcinoma. More conservative approaches could be considered for the minimal group, but prospective controlled studies should be done to determine the long-term risks of such treatment.