Rare Type of Breast Cancer Linked to Childbirth Numbers

Rare Type of Breast Cancer Linked to Childbirths

A new study finds that the more times a woman gives birth, the higher her risk of “triple-negative” breast cancer. Although this is a relatively uncommon subtype of the disease, it is very aggressive. At the same time, the study showed that women who have never had a child have a much lower risk.

Amanda Phipps, Ph.D., a postdoctoral research associate in the Public Health Sciences Division of Fred Hutchinson Cancer Research Center, published her team’s findings online and they will be published in print in the March 16 issue of the Journal of the National Cancer Institute.

“Unlike most breast cancers, triple-negative tumors don’t depend on hormonal exposures to grow and spread, so our assumption going into the study was that reproductive factors would not be associated with a woman’s risk of this cancer subtype,” Phipps said. “We were surprised by these findings because researchers have known for quite some time that women who have children, especially those who have them at an early age and have multiple full-term pregnancies, have a lower risk of breast cancer overall.”

The triple-negative breast cancer has a poorer prognosis than other types partly because it does not respond to hormone-blocking therapies.

The study makes it appear to be a trade off in that never giving birth appears to be protective against triple-negative breast cancer, but carries about a 40 percent higher risk of the most common, and most easily treated, form of the disease.