Breastfeeding one's baby can reduce by up to 59percent the risk of breast cancer in women who have a family history ofthe disease, including those who have inherited the BRCA1 or BRCA2mutation that is more commonly found in Jewish women in Israel andabroad, according to research published Monday in the prestigiousArchives of Internal Medicine.
Themajor study - by obstetrics and gynecology Prof. Alison Stuebe andcolleagues of the University of North Carolina at Chapel Hill School ofMedicine - can provide relief to women in such a situation who havereduced their risk of the cancer only by undergoing frequentexaminations by their doctors or undergoing prophylactic surgery toremove their breasts.
It follows numerous studies that show breastfeeding reduces therisk of breast cancer among women in general. But having a familyhistory of breast cancer, especially being the carrier of a BRCAmutation, can raise the lifetime risk beyond that of other women by asmuch as 80 percent.
Among women with a mother or sister with breast cancer, theresearchers found that those who had breastfed were less than half aslikely to develop premenopausal breast cancer as those who had notbreastfed.
For women with a family history, the reduction inrisk with breastfeeding was similar to taking an anti-estrogen drugsuch as Tamoxifen for five years. But unlike Tamoxifen, Stuebe says,"Breastfeeding is good for mothers and for babies."
Stuebe and colleagues reviewed data from the Nurses' HealthStudy II, a long-term study of more than 100,000 women from 14 USstates. Stuebe's study followed more than 60,000 women who reported atleast one pregnancy in 1997, when breastfeeding was assessed in detail,and followed them through 2005 to determine how many developed invasivebreast cancer.
Howlong a woman breastfed seemed to be less important than whether or notshe had breastfed, Stuebe says. The reduction in risk was similarwhether women breastfed for a lifetime total of three months or formore than three years. Also, there was no significant difference inrisk for women who breastfed exclusively versus those who breastfedwhile supplementing with other foods.
"At last - a positive study that is a continuation of theresearch of many years" that shows that breastfeeding is beneficial tomothers without a family history, commented Wendy Blumfield of theIsrael Childbirth Education Center.
"One of the theories is that menstruation usually resumes laterafter delivery when a woman is lactating and that the resulting fewermenstrual cycles in itself reduces the hormonal upheaval that cancontribute to the risk of breast, ovarian and uterine cancers. Thetheory mentioned in this study, that women who do not breastfeed have agreater tendency to infections and breast inflammation in the days andweeks following birth is also plausible.
"When one reflects that lactation is the natural conclusion tothe hormonal changes of pregnancy and birth, it is logical that thiswould contribute to the future health of the mother."
Blumfield added one word of caution.
"Inflammatory breast disease in premenopausal women is easilymasked if a woman is still or has recently stopped breastfeeding. In mywork I have unfortunately heard of women who have presented symptoms totheir doctors, only to be brushed off with an explanation that they arecaused by engorgement or other breastfeeding changes that in themselvesare quite benign. So without unduly scaring women who are worried aboutunusual changes in the breasts that do not resolve themselves within afew days, I would urge them to get a thorough check at a breast clinicor with a qualified breast specialist."
Commenting on the new research, the Israel Cancer Associationsaid it endorses the recommendation of breastfeeding not only forbabies' health but also to help protect the mothers against breastcancer.
The ICA noted that the increasingly lower age at the onset ofmenstruation among girls in Western countries - due to improper dietand inadequate exercise - raises the risk of eventual breast cancer,and that when girls reach adulthood and give birth, they should nursetheir babies if possible to cut their risk.