Women who have breastfed in the past face 30% reduced risk of breast cancer recurrence, claims a new Kaiser Permanente study.
According to the study, there was also protective effect of breastfeeding and was more pronounced for tumors of particular genetic subtypes, including the most commonly diagnosed of all breast cancers.
Dr. Marilyn L. Kwan, said that the study, which involved 1,636 women with breast cancer, was the first one where they were aware of that examined the role of breastfeeding history in cancer recurrence, and by tumor subtype.
The researchers found the benefits of breastfeeding on expected outcomes among women who were diagnosed with the luminal A subtype of breast cancer, while no significant associations were observed for those with other subtypes. Luminal A tumors include the estrogen-receptor positive (or ER+) breast tumors, which are the most commonly diagnosed of all breast cancers. These tumors are less likely to metastasize, are treatable with hormonal therapy such as tamoxifen and aromatase inhibitors, and generally have better outcomes.
In addition to this, women who breastfed were also 28% less likely to die from the disease.
Kwan noted that the research showed that breastfeeding had benefits for babies as well as moms. "In fact, the protection was even stronger for women who had a history of breastfeeding for 6 months or more."
The study is published in the Journal of the National Cancer Institute