Outcomes of special histotypes of breast cancer after adjuvant endocrine therapy with letrozole or tamoxifen in the monotherapy cohort of the BIG 1-98 trial

Munzone, E. et al. (2015) Outcomes of special histotypes of breast cancer after adjuvant endocrine therapy with letrozole or tamoxifen in the monotherapy cohort of the BIG 1-98 trial. Annals of Oncology, 26(12), pp. 2442-2449. (doi: 10.1093/annonc/mdv391) (PMID:26387144)

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Abstract

Background: We investigated the outcomes of postmenopausal women with hormone receptor-positive, early breast cancer with special histotypes (mucinous, tubular, or cribriform) enrolled in the monotherapy cohort of the BIG 1-98 trial. Patients and methods: The intention-to-treat BIG 1-98 monotherapy cohort (5 years of therapy with tamoxifen or letrozole) included 4922 women, of whom 4091 had central pathology review. Histotype groups were defined as: mucinous (N = 100), tubular/cribriform (N = 83), ductal (N = 3257), and other (N = 651). Of 183 women with either mucinous or tubular/cribriform tumors, 96 were randomly assigned to letrozole and 87 to tamoxifen. Outcomes assessed were disease-free survival (DFS), overall survival (OS), breast cancer-free interval (BCFI), and distant recurrence-free interval (DRFI). Median follow-up in the analytic cohort was 8.1 years. Results: Women with tubular/cribriform breast cancer had the best outcomes for all end points compared with the other three histotypes, and had less breast cancer recurrence (97.5% 5-year BCFI) than those with mucinous (93.5%), ductal (88.9%), or other (89.9%) histotypes. Patients with mucinous or tubular/cribriform carcinoma had better DRFI (5-year rates 97.8% and 98.8%, respectively) than those with ductal (90.9%) or other (92.1%) carcinomas. Within the subgroup of women with special histotypes, we observed a nonsignificant increase in the hazard of breast cancer recurrence with letrozole [hazard (letrozole versus tamoxifen): 3.31, 95% confidence interval 0.94–11.7; P = 0.06]. Conclusions: Women with mucinous or tubular/cribriform breast cancer have better outcomes than those with other histotypes, although the observation is based on a limited number of events. In postmenopausal women with these histotypes, the magnitude of the letrozole advantage compared with tamoxifen may not be as large in patients with mucinous or tubular/cribriform disease.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Gusterson, Professor Barry
Authors: Munzone, E., Giobbie-Hurder, A., Gusterson, B. A., Mallon, E., Viale, G., Thürlimann, B., Ejlertsen, B., MacGrogan, G., Bibeau, F., Lelkaitis, G., Price, K. N., Gelber, R. D., Coates, A. S., Goldhirsch, A., and Colleoni, M.
College/School:College of Medical Veterinary and Life Sciences > School of Cancer Sciences
Journal Name:Annals of Oncology
Publisher:Oxford University Press
ISSN:0923-7534
ISSN (Online):1569-8041

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