This article is more than 5 years old. Information may no longer be current.
Breastfeeding may protect against aggressive breast cancers
Click Here to Manage Email Alerts
Breastfeeding conferred a protective effect against hormone receptor-negative breast cancers, according to the results of a systematic review and meta-analysis.
However, the association between breastfeeding and hormone receptor (HR)-positive breast cancer remained unclear, according to the researchers.
“Further evidence to support the long-term protection of breastfeeding against the most aggressive subtypes of breast cancer is very encouraging and actionable,” Marisa Weiss, MD, director of breast radiation oncology and breast health outreach at Lankenau Medical Center in Wynnewood, Pa., as well as founder and president of breastcancer.org, said in a press release. “Breastfeeding is a relatively accessible, low-cost, short-term strategy that yields long-lasting natural protection.”
Breastfeeding is inversely associated with the overall risk for breast cancer, according to study background. However, the association may differ in breast cancer subtypes defined by HR status.
Thus, Weiss and colleagues conducted a systematic review and meta-analysis of case-control and prospective cohort studies to observe the association between breastfeeding and breast cancer, stratified by ER, PR and HER-2 status.
The researchers searchers PubMed and Scopus databases, as well as bibliographies of relevant articles, to identify appropriate articles for the meta-analysis. The meta-analysis included data from 27 studies (cohort, n = 8; case-control, n = 19), comprising a total of 36,881 women with breast cancer.
Among parous women, similar risk estimates occurred for the association between ever breastfeeding vs. never breastfeeding and ER- and PR-negative breast cancers in three cohort and three case-control studies after adjustment for factors such as the number of full-term pregnancies. The combined OR from these studies demonstrated a reduction in risk for these breast cancers with breastfeeding (combined OR = 0.9; 95% CI, 0.82-0.99). The researchers judged these studies to have no indication of publication bias, as well as little heterogeneity.
Paolo Boffetta
In a subset of studies that included ER, PR and HER-2 status, breastfeeding showed a stronger inverse association with triple-negative breast cancer (OR = 0.78; 95% CI, 0.66-0.91) among parous women.
However, cohort studies showed no significant association between breastfeeding and reduced risk for ER-positive and/or PR-positive breast cancers. Researchers noted the only cohort studies that showed inverse associations were from different, non-overlapping phases of a cohort of relatively young nurses.
The researchers acknowledged limitations to their analysis, such as the inclusion of only English language studies and the risk for bias associated with systematic reviews.
“Pregnant women and young mothers are highly receptive and motivated to make healthy choices,” Paolo Boffetta, MD, associate director for population sciences at Tisch Cancer Institute at the Icahn School of Medicine, said in a press release. “We need to encourage women who are able to breastfeed to do so for their breast health, in addition to the health of their children. Further prospective research will be necessary to further understand the full impact of breastfeeding duration and its effect on other subtypes." – by Cameron Kelsall
Disclosure: The researchers report no relevant financial disclosures.
Click Here to Manage Email Alerts