Does antiperspirant cause breast cancer?

Dear Cecil: Is there any proven link between the use of antiperspirant and breast cancer in women? Bill Burson

Cecil replies:

Bill forwards the following E-mail message that’s been making the rounds:

Breast cancer prevention

Not just for women — men, don’t forget to tell mom, cousins, etc. I just got information from a health seminar that I would like to share. The leading cause of breast cancer is the use of antiperspirant. Yes, ANTIPERSPIRANT. Most of the products out there are an antiperspirant/deodorant combination, so go home and check your labels. Deodorant is fine, antiperspirant is not. Here’s why. The human body has a few areas that it uses to purge toxins: behind the knees, behind the ears, groin area, and armpits. The toxins are purged in the form of perspiration. Antiperspirant, as the name clearly indicates, prevents you from perspiring, thereby inhibiting the body from purging toxins from below the armpits. These toxins do not just magically disappear. Instead, the body deposits them in the lymph nodes below the arms since it cannot sweat them out. This causes a high concentration of toxins and leads to cell mutations, aka CANCER. Nearly all breast cancer tumors occur in the upper outside quadrant of the breast area. This is precisely where the lymph nodes are located. Men are less likely to develop breast cancer prompted by antiperspirant usage because most of the antiperspirant product is caught in their hair and is not directly applied to the skin. Women who apply antiperspirant right after shaving increase the risk further because shaving causes almost imperceptible nicks in the skin, which give the chemicals entrance into the body from the armpit area.

This takes us into the gray world of environmental medicine, where you can’t prove anything — or disprove it either. Do you know FOR A FACT that cancer isn’t caused by fluoridation, electric power lines, or cosmic rays?

Nonetheless, it seems pretty certain this particular scare story is false. In a statement issued last year, the American Cancer Society said: (1) Among the many epidemiological studies of breast cancer, “we are not aware of any . . . proving or even suggesting antiperspirant use as a risk factor for breast cancer, much less the ‘leading cause’ of the disease.” (2) Some toxins are collected by the lymph glands, but they’re not eliminated through sweat. (3) Half, not all, of breast cancers occur in the “upper outer quadrant” — not because of the lymph nodes, but because that’s where a lot of breast tissue is, including the “axillary tail,” which extends toward the underarm. (4) “Men are about 100 times less likely than women to develop breast cancer. This is because they have about 100 times less breast tissue. … Razor nicks can increase the risk of infection but not cancer.”

Antiperspirants aren’t the only commercial product blamed for breast cancer. Other suspects: (1) Excessively tight bras, which supposedly prevent toxins from being flushed out of the breast/lymph area. I don’t know of any study specifically refuting this claim, which comes from Sydney Ross Singer’s 1995 book Dressed to Kill: The Link Between Breast Cancer and Bras. I don’t know of any study specifically refuting the idea that breast cancer is caused by cornflakes, either. (2) Chlorinated pesticides. Scientists take this claim more seriously, although a recent study suggests chlorine is not at fault. Then again, the study was funded by the chlorine industry, so who knows?

That’s just it, you see. One never knows. What we do know is that breast cancer is the most common invasive cancer in women and that the rate of breast cancer rose steadily during the 70s and 80s. (The rate has been basically flat since 1990.) One woman in nine will get the disease. Because we have no clear understanding of what causes cancer, “there’s never any shortage of imaginative hypotheses,” says Dr. Michael Thun, head of epidemiological research for the ACS.

Still, we can make a few generalizations. First, the rising reported rate of breast cancer in part was a function of improved screening, including mammography. Second, the leading cause of this cancer appears to be a woman’s own menstrual cycle, which causes periodic cell division in breast tissue. The more periods a woman has, the more cell division occurs and the greater the chances of a reproductive mistake giving rise to breast cancer. Women today begin menstruating sooner due to improved diet, have their menstrual cycles interrupted by fewer pregnancies, and live longer, giving breast cancer more time to appear. Better screening, better diet, and fewer pregnancies have produced a curious circumstance: women of higher socioeconomic status are more likely to get breast cancer. (White women get breast cancer at a higher rate than black women, although black women are more likely to die of it.) This is not the ideal message to send to young women: “Want to avoid breast cancer? Become a teenage mom!” But it does show that affluence isn’t an unmitigated boon.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.