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Ann Oncol. 2015 Dec;26(12):2442-9. doi: 10.1093/annonc/mdv391. Epub 2015 Sep 19.

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.

Author information

1
Division of Medical Senology, European Institute of Oncology, Milan, Italy elisabetta.munzone@ieo.it.
2
Department of Biostatistics and Computational Biology, International Breast Cancer Study Group (IBCSG) Statistical Center, Dana-Farber Cancer Institute, Boston, USA.
3
Institute of Cancer Sciences, Glasgow University, Glasgow.
4
Southern General Hospital, Glasgow, UK.
5
Department of Pathology and Laboratory Medicine, IBCSG Central Pathology Laboratory, European Institute of Oncology, and University of Milan, Milan, Italy.
6
Breast Center, Kantonsspital, St Gallen Swiss Group for Clinical Cancer Research (SAKK), Bern, Switzerland.
7
Danish Breast Cancer Cooperative Group (DBCG), Rigshospitalet, Copenhagen, Denmark.
8
Department of Pathology, Institut Bergonié, Bordeaux.
9
Department of Pathology, Val d'Aurelle Cancer Institute, Montpellier, France.
10
Department of Pathology, Rigshospitalet, Copenhagen, Denmark.
11
International Breast Cancer Study Group (IBCSG) Statistical Center.
12
Department of Biostatistics and Computational Biology, International Breast Cancer Study Group (IBCSG) Statistical Center, Dana-Farber Cancer Institute, Boston, USA Harvard T.H. Chan School of Public Health, Harvard Medical School, Frontier Science and Technology Research Foundation, Boston, USA.
13
International Breast Cancer Study Group, Bern, Switzerland University of Sydney, Sydney, Australia.
14
Program of Breast Health, European Institute of Oncology, Milan, Italy.
15
Division of Medical Senology, European Institute of Oncology, Milan, Italy.

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.

CLINICALTRIALSGOV:

NCT00004205.

KEYWORDS:

breast cancer; cribriform; letrozole; mucinous; tamoxifen; tubular

PMID:
26387144
PMCID:
PMC4658543
DOI:
10.1093/annonc/mdv391
[Indexed for MEDLINE]
Free PMC Article

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