It has long been believed that breastfeeding beyond a year reduces the risk of breast cancer in women. Just last year the New York Times reported:
There is new evidence that breast-feeding is associated with a lower incidence of breast cancer among a group of younger women who are at particularly high risk: those with breast cancer in the family…
But Dr. Stuebe suggested 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.
Though breast-feeding is promoted primarily because it is linked to better health in babies, mothers seem to accrue long-term advantages. Studies have found that women who breast-fed are less likely to develop osteoporosis and ovarian cancer, as well as high blood pressure and heart disease decades later.
The American Cancer Society agrees, “Some studies have shown that breast-feeding slightly lowers breast cancer risk, especially if the breast-feeding lasts 1½ to 2 years. This could be because breast-feeding lowers a woman’s total number of menstrual periods, as does pregnancy.”
Shockingly, a new study contradicts these previous studies. Press TV explains:
Latest figures have revealed that women diagnosed with breast cancer after completing a pregnancy are 48 percent more likely to die compared with other women suffering from the disease.
Previous studies had suggested that breastfeeding lowers the risk of breast malignancies particularly in high-risk women who have a positive family history for the disease.
According to the study presented at the seventh European Breast Cancer Conference (EBCC7) in Barcelona, women who breastfed their newborns for more than six months are two times more likely to have grade III breast tumors.
I have a hard time accepting this new study, when multiple previous studies contradict the results. Breastfeeding is hardly to blame, especially when the biggest message coming out of EBCC7 is that 1/3 of all breast cancers could be eliminated “if women ate less and exercised more”. As lead researcher of the breastfeeding study Angela Ives cautions, “It is important to stress that our findings should not discourage women from breast feeding as we know that this is beneficial to both mother and baby in a number of ways.”
Hard to believe!
The little bit of the report included in this article doesn’t give clear stats. They’re “two times more likely to have grade III tumors” — two times more likely than who? It doesn’t sound like it’s saying “two times more likely to GET cancer”, but that those who DO get it are more likely to have serious tumours than those that did not BF as much.
That’s not the same thing as increasing breast cancer risk. You could still be 10 times less likely to get cancer in the first place, just more likely for it to be serious if you do get it.
Without the numbers, we don’t know what that “2x more” is referring to. Does it mean “out of the 60 BFing women who got cancer, 40 had grade 3, and out of the 200 non-BF women who got cancer, 20 had grade 3” — or does it mean “out of the BFing women, 40% had grade 3, and out of the non-BF women, 20% had grade 3” — there’s a BIG difference.
It’s possible that it could be interpreted as “long-term BFing offers signifciant protection against lower-grade breast cancers, but little against serious cancers”. By removing lower-grade cancers from the BF group, that would artificially inflate the apparent occurrence of the more serious one. In other words — is the mechanism behind the higher number the fact that lower-level cancers are REPLACED by grade III, or that the lower-level cancers are REDUCED, causing an OVERALL reduction in breast cancer rate, but an apparent increase in the serious-cancer rate.
Anyway, without the numbers, it’s impossible to know. I’m just offering one possible explanation that could unify these apparently disparate studies.
Heather, thanks for you comment. As you see from the original Press TV link, there wasn’t much to the original story, and I couldn’t find any information from the conference itself. It is true the study focuses on the more serious tumors and found death more likely for breastfeeding moms, but these tumors are more serious, and I don’t the size of the study either. I also changed the post title to more accurately reflect the study.
I don’t think you guys should just post this based on this short link from some presstv.ir website. its one thing to offer readers information on whats out there, but i think (because you made me nervous now) that you know yours sources better. if you don’t know the size of the study (which is very important to see what the numbers actually mean) that you need to either, do more research about it or not post it. I really wonder if this was a ligitimate stufy. I will check back later to see if you guys find a better source than this website. If it’s really like they say it is, than you should be able to find more numbers, more data on the pool and so on. Its an interesting topic, but such a shocking headline for basically no real ligitimate information and proof from either you or the source, i would conduct more research.
Okay, this article refers to 2 different abstracts presented at the EBCC 7 conference. Remember that abstracts are not the complete article or presentation of the full study but are summaries AND remember that lots of studies are presented at conferences but a relatively few number actually make publication in a peer-reviewed journal (this is a very important distinction for people familiar with medical publications).
The first figure regarding a 48% increase risk of death involved a study of Gestational Breast Cancer and is specific to those women diagnosed within 12 months postpartum. GBC occurs about 1 in every 3000 pregnancies. It is very likely that women with a genetic predisposition for breast cancer are over-represented in this group. The study specifically differentiated those patients diagnosed with BC during pregnancy and those diagnosed during the postpartum period. Those diagnosed during the postpartum period had the increased risk of death. They concluded that pregnancy and breast feeding likely had some effect on prognosis but that this required more investigation. And again this is GBC, which is rare and very likely the women have an underlying genetic predisposition–thus this is NOT applicable to the general population as of now.
Now in regards to the other statistics. This was as study out of Sweden of over 17,000 women for 10+ years. Overall breast cancer risk was similar for ALL periods of breast feeding! In women who breast fed longer (defined as >6.2 months) there was an increase in grade III tumors. In addition when breast feeding times were totaled those with the longest totals also should an increase incidence in the grade III tumors. As someone else eluded to, the actual rates of breast cancer were not changed by varying lengths of breast feeding only an increased risk of higher grade tumors.
I hope that helps clear the air. Interesting study that needs more investigation and should not have any current implications on women’s decision to breast feed:)
The abstracts can be found on the EBCC7 website–it does require a bit of searching and again the complete articles/presentations were not available.
Here’s more to the story:
http://www.examiner.com/examiner/x-23788-Mankato-Attachment-Parenting-Examiner~y2010m3d31-Media-scares-breastfeeding-mothers-with-alarmist-cancer-study
First, I never intended to scare anyone. In fact, a majority of this article is about the benefits, including the study’s lead author’s concluding remark. If you eat junk and don’t exercise, then you should be nervous.
Jamie, I really appreciate the info you dug up. If you get a chance, please post the links from EBCC7.
in china ,the doctors often advice mother to breastfeeding baby not more than one year, breastfeeding is useful to both baby and mother!!
What people here are saying about the conclusions of this study not seeming well supported based merely on what is available in that news release, well you know, one can say about the arguments in support of breastfeeding long term. Everybody knows those benefits were greatly exaggerated by La Leche League and various other organizations. If that’s not okay to do here in this study why is okay when somebody else does it? It’s creepy how this can seem a war where people take one side or another or gloat whether new data allows them to feel righteous that day or not. The more actual truth and data that comes out is always good. It allows women to make the choice that is right for them and their families. I think it’s incredibly selfish to immediately dismiss this study because it doesn’t match your personal beliefs. My oldest friend who does have the gene for breast cancer would find this study very valuable to know about and look into further.