Breast-Feeding May Cut Cancer Risk Among High-Risk Women

By Allison Bond | August 11, 2009 2:45 pm

mother and childBreast-feeding may significantly cut a woman’s risk of breast cancer if she has an immediate relative that has ever had the disease, according to a study published in the journal Archives of Internal Medicine.

Among women with close family members who have had breast cancer, the risk of developing the disease before menopause sank by 59 percent if she ever breast-fed, according to the research, which used data from more than 60,000 subjects of the Harvard Nurses’ Health Study. The risk of breast cancer in women without the disease in the family was unaffected by breast-feeding. The findings suggest that breast-feeding may prove just as effective a strategy for high-risk women as the use of Tamoxifen, a drug that interferes with estrogen activity and is often used in high-risk women to reduce breast cancer risk [The New York Times]. For women with a high risk of breast cancer, due to factors like a family history of the disease or a genetic predisposition to develop it, the only preventive measures currently used are Tamoxifen and the prophylactic removal of the breasts.

While the study showed breast-feeding provided a large protective effect, the finding may not be entirely definitive. Oncologist Julia Smith notes that 87 percent of the women in the study breast-fed their infants, a much higher percentage than women in the general population, and that the women who breast-fed tended to be thinner than women who did not. The drop in breast cancer risk may have been due to other lifestyle factors rather than just breast-feeding alone [Health]. For instance, breast-feeding is more common among higher-income, better-educated women, who may engage in other behaviors that are providing protection against breast cancer.

Finally, the fact that breast cancer risk did not appear to be affected by the length of time during which a woman breast-fed raised a red flag among some experts about the conclusions of the research. “I would be cautious in interpreting [these results]… You would expect to see a dose-response relationship with breast-feeding if it is a really causal protective factor” [The New York Times], said epidemiologist Louise Brinton.

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Image: flickr / ECohen

CATEGORIZED UNDER: Health & Medicine
  • cory

    The comment regarding a “dose- response relationship” sounds reasonable on the surface. But it strikes me that it’s the process of lactating itself, the hormonal changes involved in both the breast itself and the circulating levels of oxytoxin and prolactin involved in breastfeeding, and the fact that breastfeeding in general lowers estrogen levels for several months that needs to be looked at.
    Every woman who has breastfeed for a long term knows that breastfeeding an infant will keep your levels low (ie, your period and your fertility absent) for several months but eventually your body re-adjusts and nursing can continue along with monthly cycles and even subsequent pregnancies. After that initial 6 months or so levels go back to normal, just with the additional nursing feedback loop.
    However the biological changes in the breast itself due to the physical act of nursing are a one-per-pregnancy thing–could those changes themselves be what is the protective effect, not the duration of nursing, but the act of changing from a non-lactating body to a lactating one? This happens with each pregnancy. Does the risk of breast cancer go down with each child breastfed, or do the numbers stay the same regardless of number of pregnancies?

  • Wesley

    They could test the idea by inducing lactation in high-risk childless women and compare them to a control group (admittedly in this case they wouldn’t be able to use a placebo for the control group). It could become a prophylactic treatment for high-risk women that don’t have or don’t plan on having children.

    In a completely different vein, why haven’t they tried inducing lactation in women trying to lose weight, considering the number of calories lost through breastmilk…

  • Sigmunds signal

    What kind of vain, selfish woman won’t breast feed to begin with? Besides the reduced health risks to the mother, what about the child? Childbirth is a miracle of nature, and some women will sacrifice their babies lifelong physical immunity, and emotional well being, just to keep their boobs from sagging for an extra five years! With all of the breast augmentation in our society, and the ideals placed upon an unrealistic body images, its no wonder western culture looks so ridiculous!

  • marilyn

    It is not just the vain and selfish who won’t breastfeed. There are women not capable of producing enough milk, HIV + status where breast feeding puts the infant at more risk, or have had previous breast surgeries for health reasons not related to augmentation that might result in nursing issues( any number of non-vain reasons including breast reduction for mental and physical health reasons and mastectomies and the not trivial, inverted nipples). Not included in this are the women who must take medication that is harmful to infants at an adult dose. Some women sacrifice their health for the period of gestation and must return to their own meds as soon as possible afterward.
    Personally I fed all of my children for beyond a year each but I cringe when I hear condemnation of such a personal choice and decision.
    I am glad to hear that there are serious considerations of altenatives that might just be related to physiology and with minimal use of pharmaceuticals. This is exciting and not quite revolutionary news. The breast cancer/breast feeding relationship has been bandied about in the past. That it might be as powerful as tamoxifen is something else entirely.
    I forsee a win win for at risk women without any wish for children donating (or banking) their milk for other infants use. The organization oversight on that boggles the mind but then again….

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