Reproductive factors and molecular subtypes of breast cancer among premenopausal women in Latin America: the PRECAMA study

Isabelle Romieu,Angélica Ángeles-Llerenas,Gloria Inés Sánchez,Mathilde His,Marion Carayol,Carine Biessy,Eva Bustamante,Carolina Porras,Rebecca Ocampo,Roberto Jaramillo,Ana Cecilia Rodríguez ,Peggy L Porter ,Gabriela Torres-Mejı́a ,Magalí Olivier ,María Luisa Garmendia ,Édgar Navarro ,Sabina Rinaldi

doi:10.1038/s41598-018-31393-7

Abstract

Etiological differences among breast cancer (BC) subtypes have not been clearly established, especially among young women in Latin America. This study examined the relationship between reproductive factors and BC subtypes among 288 BC cases (20–45 years) and population-based matched controls in four Latin American countries. Immunohistochemistry was determined centrally. Associations between BC and reproductive factors were determined. Older age at first full-term pregnancy (FFTP) (Odds Ratio (OR) = 1.11; 95% Confidence Interval (CI), 1.04–1.19 per year), longer time between menarche and FFTP (OR = 1.12; 95%CI: 1.04–1.20 per year), and older age at last pregnancy (OR = 1.10; 95%CI, 1.02–1.19 per year) were associated with an increased risk of estrogen receptor positive (ER+) tumors (n = 122). Ever pregnant (OR = 0.35; 95%CI, 0.13–0.96), number of childbirths (OR = 0.64; 95%CI, 0.47–0.87 per child), time since last birth (OR = 0.92; 95%CI, 0.85–0.99 per year), and history of breastfeeding (OR = 0.23; 95%CI, 0.09–0.58) were inversely associated with the risk of ER+ tumor. Older age at menarche (OR = 0.63; 95%CI, 0.45–0.89 per year) and longer duration of breastfeeding (OR = 0.97; 95%CI, 0.94–1.01 per month) were inversely associated with estrogen receptor negative (ER-) tumors (n = 48). Reproductive factors may be differentially associated with BC subtypes in young Latin American women.

Highlights

Breast cancer (BC) in young women is a leading cause of death and remains so despite more intensive treatment than in older women[1]
In Latin American (LA) women, 20% of BC occurs at ages 20–45 years, a higher proportion than in Westernized populations[2], and this substantial number of incident BC cases among young LA women can only be partly explained by the population age structure[3]
Few studies have focused on risk factors for BC in young women, and these studies have mainly been conducted in Caucasian women[8], with only limited data in Latin American or U.S Hispanic women[2,9]

Summary

Introduction

Breast cancer (BC) in young women is a leading cause of death and remains so despite more intensive treatment than in older women[1] This may be related to different risk factors and tumor biology in young women. In Latin American (LA) women, 20% of BC occurs at ages 20–45 years, a higher proportion than in Westernized populations[2], and this substantial number of incident BC cases among young LA women can only be partly explained by the population age structure[3] This understudied population is currently undergoing significant reproductive and lifestyle transitions[4] that offer unique contrasts in exposures to study factors associated with BC subtypes. We focus on the role of reproductive factors

Methods

Results

Conclusion