Tumor subtype-specific associations of hormone-related reproductive factors on breast cancer survival.

Abstract

PURPOSE:

It is inconclusive whether reproductive factors, which are known as risk factors of breast cancer, also influence survival. We investigated overall and subtype-specific associations between reproductive factors and breast cancer survival.

METHODS:

Among 3,430 incident breast cancer patients who enrolled in the Seoul Breast Cancer Study, 269 patients (7.8%) died and 528 patients (15.4%) recurred. The overall and subtype-specific associations of reproductive factors including age at menarche and menopause, duration of estrogen exposure, menstrual cycle, parity, age at first full-term pregnancy, number of children, age at last birth, time since the last birth, and duration of breastfeeding, on overall and disease-free survival (OS and DFS) were estimated by hazard ratios (HRs) and 95% confidence intervals (95% CIs) using a multivariate Cox proportional hazard model.

RESULTS:

An older age at menarche (HR for OS=1.10, 95% CI=1.03-1.19), a greater number of children (≥ 4 vs. 2, HR for DFS=1.58, 95% CI=1.11-2.26), and a shorter time since last birth (<5 vs. ≥ 20 years, HR for DFS=1.67, 95% CI=1.07-2.62) were associated with worse survival while longer duration of estrogen exposure with better survival (HR for DFS=0.97, 95% CI=0.96-0.99). In the stratified analyses by subtypes, those associations were more pronounced among women with hormone receptor and human epidermal growth factor 2 positive (HR+ HER2+) tumors.

CONCLUSIONS:

It is suggested that reproductive factors, specifically age at menarche, number of children, time since last birth, and duration of estrogen exposure, could influence breast tumor progression, especially in the HR+ HER2+ subtype.

• Authors: Nan Song, Ji-Yeob Choi, Hyuna Sung, Sujee Jeon, Seokang Chung, Minkyo Song, Sue K Park, Wonshik Han, Jong Won Lee, Mi Kyung Kim, Keun-Young Yoo, Sei-Hyun Ahn, Dong-Young Noh, Daehee Kang
• Journal: PloS one (PLoS One) Vol. 10 Issue 4 Pg. e0123994 ( 2015) ISSN: 1932-6203 [Electronic] United States
• PMID: 25875532 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Receptors, Estrogen
• Receptors, Progesterone
• Receptor, ErbB-2

Topics

• Adult
• Aged
• Breast Neoplasms (metabolism, mortality, pathology)
• Demography
• Disease-Free Survival
• Female
• Follow-Up Studies
• Humans
• Menarche
• Menopause
• Middle Aged
• Proportional Hazards Models
• Receptor, ErbB-2 (metabolism)
• Receptors, Estrogen (metabolism)
• Receptors, Progesterone (metabolism)
• Risk Factors
• Survival Rate