Hwang, ES

Abstract Background: Standard treatment for ductal carcinoma in situ (DCIS) consists of surgery, often followed by adjuvant radiation therapy or endocrine therapy. This current approach is thought to represent overtreatment for some patients. This study was undertaken to determine whether an alternate approach of primary endocrine therapy alone could result in measurable radiographic changes in unresected estrogen receptor (ER)-positive DCIS. Methods: A phase II open-label single arm multi-center cooperative group trial (CALGB 40903) was conducted for postmenopausal patients diagnosed with ER-positive DCIS. All eligible patients underwent baseline mammography and MRI, followed by 6 months of preoperative therapy with letrozole. Follow up breast MRI was obtained at 3 and 6 months of treatment. The primary endpoint was change in total MRI volume of DCIS enhancement from baseline to 3 months and from baseline to 6 months. Secondary endpoints were change in MRI maximum diameter over baseline and change in mammographic extent of disease over baseline. Endpoints were analyzed via 2-sided paired t-tests (a=0.05). Results: From 8/1/12 to 2/1/16 108 patients were enrolled; Of the 77 patients who completed letrozole treatment per protocol, 66 patients were assessable. 2 additional patients who did not complete treatment per protocol were considered assessable and thus included in the analysis for a total of 68 patients. Median age of the cohort was 62.7 years. DCIS nuclear grade was low in 10% of patients, intermediate in 49%, and high in 40%. 82% of patients had ER-positive, PR-positive DCIS. The total mean MRI volume decreased from baseline to 3 months by 1.93 cm3 (p<0.001) and from baseline to 6 months by 1.82 cm3 (p<0.001). There was no significant difference in tumor volume between 3 and 6 months. Mean total mammographic tumor diameter decreased from baseline to 6 months by 3.31 mm2 (p=0.078). Conclusions: In a cohort of postmenopausal women treated with 6 months of preoperative endocrine therapy for ER-positive DCIS, MRI volume decreased markedly by 3 months, while mammographic extent of disease was not altered significantly. Correlation of imaging changes with pathology and baseline biomarkers will be conducted. These results will help determine whether MRI could be an effective modality for monitoring treatment response in some patients treated with primary endocrine therapy for ER-positive DCIS. Citation Format: Hwang ES, Duong S, Bedrosian I, Allred J, Wisner D, Hyslop T, Caudle A, Guenther J, Hudis C, Winer E, Esserman L, Hylton N. Primary endocrine therapy for ER-positive ductal carcinoma in situ (DCIS) CALGB 40903 (Alliance) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr GS5-05.

Abstract Background: Retrospective studies suggest that primary breast surgery is associated with improved overall survival (OS) in Stage IV breast cancer. TBCRC 013 is a multi-center prospective registry study evaluating the role of surgery for the primary tumor in Stage IV disease. Methods: From 7/09 - 4/12, 128 eligible pts from 14 sites were enrolled in two cohorts (A: Stage IV with intact primary tumor (n = 112); B: metastases (mets) within 3 months of primary surgery (n = 16)). Baseline patient and tumor characteristics, and surgery of the primary were correlated with 2yr overall survival (OS) using log rank, Kaplan Meier and Cox regression for all patients. Comparisons were also made between cohorts A and B and within cohort A stratified by response to systemic therapy. Responders included those with any response (partial,complete) or stable disease at distant sites. Results: Median pt age was 52yrs(21-79) and median primary tumor size 3.2cm(0.7-15). Phenotypes were ER+ 106 (83%), HER2neg 91(71%), and triple neg 10(8%). 60(47%) had bone-only mets. The only significant baseline difference between cohorts A and B was the presence of palpable nodes (A:62% vs B:0%, p<0.001). There were no differences in age, tumor size, ECOG scores, ER or HER2 status, number or sites of mets between cohorts A and B. At a median follow-up of 25 mo (95%CI, 23-31), 2yr OS for all pts is 86% (80-92) and is superior in cohort B as compared to A, (100% vs 84%, p = 0.03). On multivariate analysis (MVA) including all pts, only surgery, ER and HER2 positivity were associated with improved OS (table). Among 112 pts with an intact primary (Arm A), 17(15%) were non-responsive (NR) to systemic therapy, 3(18%) of whom required palliative surgery at a median time of 10.4mos. 2yr OS among NR was 33% (15-69) as compared to 94% (88-99) in Arm A responders (R) (p<0.001). ER positivity was the only baseline difference between NR (65%) and R (88%) within Arm A (p = 0.02). Among 94(85%) Arm A responders, 39(41%) had elective surgery (median 8.4 mos, 95%CI:6.9-10.3) and only 1 of the remaining 47(2%) required palliation. When limited to Arm A responders, elective surgery was not associated with improved 2yr OS (surgery vs not: 94% vs 92%, p = 0.5). Median time to progression following elective surgery was 12 mos (95%CI,8-19mos). When cohort B (n = 16) and cohort A surgery groups (n = 39) are combined, surgery of the primary tumor is associated with improved 2yr OS (96% vs 74%, p = 0.002). Conclusions: In this prospective registry study, patients diagnosed with mets within 3 months of primary breast surgery have an improved 2yr OS. When all pts having surgery (A + B) are examined, surgery is associated with improved OS on MVA, but when limited to Arm A responders, elective surgery does not improve OS. Given that the number of Arm A responders is small, results from the prospective randomized trial will be needed to address this question. These data also demonstrate that the need for surgical palliation of the primary tumor is uncommon in the modern era. Multivariate Analysis for OSN = 128HR Death (95%CI)pvalueSurgery0.28 (0.10-0.74)0.01ER positivity0.28 (0.10-0.72)0.01HER2 positivity0.21 (0.06-0.74)0.01MVA included: age, tumor size, ECOG, ER, PR, HER2, met sites, and surgery Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-18-09.