Risk of Breast Cancer Reoccurrence Lowered After Breastfeeding

Proving true the popular adage that breastfeeding can keep mothers healthy, a study has shown it offers protection against breast cancer reoccurrence.

Breastfeeding is known to lower risk of breast cancer in women who feed for a year or longer. The current study done by researchers at Kaiser Permanente Division of Research shows that breastfeeding can offer protection against certain cancer subtypes, including the most commonly occurring estrogen-receptor positive type. The study found that breastfeeding reduced risk of reoccurrence by 30 percent.

While the study did not clearly explain why breastfeeding may be beneficial, researchers had a few theories.

"Breastfeeding may increase the maturation of ductal cells in the breast, making them less susceptible to carcinogens or facilitate the excretion of carcinogens, and lead to slower growing tumors," said Bette J. Caan, the study's senior author.

The study involved 1,636 women with breast cancer. Researchers also found that breastfeeding reduced risk of dying from the disease by 28 percent.

"Women who breastfeed are more likely to get the luminal A subtype of breast cancer, which is less aggressive, and breastfeeding may set up a molecular environment that makes the tumor more responsive to anti-estrogen therapy," Kwan said Marilyn L. Kwan, the study's lead author.

The study's findings have been published in the Journal of the National Cancer Institute.