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Clinical behavior of recurrent hormone receptor–positive breast cancer by adjuvant endocrine therapy within the Breast International Group 1‐98 clinical trial
Author(s) -
Leone Jose P.,
Cole Bernard F.,
Regan Meredith M.,
Thürlimann Beat,
Coates Alan S.,
Rabaglio Manuela,
GiobbieHurder Anita,
Gelber Richard D.,
Ejlertsen Bent,
Harvey Ver J.,
Neven Patrick,
Láng Istvan,
Bonnefoi Herve,
Wardley Andrew,
Goldhirsch Aron,
Di Leo Angelo,
Colleoni Marco,
VazLuis Ines,
Lin Nancy U.
Publication year - 2021
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.33318
Subject(s) - medicine , letrozole , tamoxifen , breast cancer , hazard ratio , interquartile range , oncology , cancer , gastroenterology , confidence interval
Background Endocrine therapy resistance is a major cause of distant recurrence (DR) in hormone receptor–positive breast cancer. This study evaluated differences in survival after DR in patients treated with different adjuvant endocrine therapy regimens in the Breast International Group (BIG) 1‐98 trial. Methods BIG 1‐98 compared 5 years of adjuvant treatment among 4 arms: tamoxifen (T), letrozole (L), tamoxifen followed by letrozole (TL), and letrozole followed by tamoxifen (LT). After a median follow‐up of 8.1 years, 911 of 8010 patients (T, 302; L, 285; TL, 170; and LT, 154) had DR as the site of first recurrence. Univariate and multivariate Cox analyses were performed to determine features associated with post‐DR survival. Results The median follow‐up time after DR was 59 months (interquartile range, 29‐88 months). Among all patients with DR, 38.1% were 65 years old or older at enrollment, 61.9% had tumors larger than 2 cm, and 69.7% were node positive. Neoadjuvant or adjuvant chemotherapy was administered to 35.6% of the patients. There was no difference in post‐DR survival by treatment arm (median survival, 20.8 months for T, 17.9 months for L, 17.3 months for TL, and 20.8 months for LT; P = .21). In multivariate analysis, older patients (hazard ratio [HR], 1.35; 95% confidence interval [CI], 1.15‐1.59) and patients with tumors larger than 2 cm (HR, 1.19; 95% CI, 1.00‐1.41), 4 or more positive nodes (HR, 1.31; 95% CI, 1.05‐1.64), progesterone receptor (PR)–negative tumors (HR, 1.25; 95% CI, 1.02‐1.52), or shorter disease‐free survival (DFS) had significantly worse post‐DR survival. Conclusions Treatment with adjuvant T, L, or their sequences was not associated with differences in survival after DR. Significant differences in survival were observed by age, primary tumor size, nodal and PR status, and DFS, and this suggests that traditional baseline high‐risk features remain prognostic in the metastatic setting.