By Heather Millar
I know a woman from a support group has not touched a drop of alcohol since her diagnosis with breast cancer several years ago. I also know survivors who regularly have wine with dinner. I am one of the latter group.
I have lots of reasons that I continue to imbibe: One, I like wine. My parents grew up in Napa, and used to be in the wine business; you could say my taste for fermented grapes is “bred in the bone.” Two, I drink moderately and not to excess: a couple glasses, maybe a little more at a party. Three, I don’t want to live the rest of my life in constant fear that this bogeyman or that bogeyman will increase my risk of a recurrence. I want to live, and that means doing things I enjoy: wine and food are one of life’s great pleasures in my book.
So I noted with interest when late last week, a new study came out in the Americal Journal of Public Health that backs up many previous studies showing that there is a link between alcohol consumption and cancer. In this case, the study shows that alcohol may be linked to about 3 percent of cancer deaths. Or, as a WebMD news story about the study put it: approximately 1 in 30 cancer deaths may be linked to drinking.
That’s not nothing. But it’s nowhere near as overwhelming as the research that shows smoking cigarettes causes cancer. The American Cancer Society reports that 87 percent of lung cancers are linked to smoking. A 2009 study showed that 70 percent of the cancer death burden in Massachusetts could be linked to smoking, though most estimates put that figure at around 30 percent—that smaller figure is ten times larger than the number of death linked to alcohol in last week’s study.
Certainly, people should know that alcohol consumption comes with risks, but they are not as huge as the risks that come with smoking. I don’t think we’ve yet proved that there’s a straight line from drinking wine with dinner to an agonizing cancer metastasis and death.
Absolutely, there are reasons for concern: Drinking can cause weight gain, and being overweight increases the risk of cancer. Alcohol seems to increase estrogen, which is a trigger for estrogen-reactive breast cancers (as mine was, by the way). Also, when our bodies get a hold of alcohol, various organs metabolize that booze into bad things like formaldehyde (a known carcinogen) and “oxygen-reactive species” (a fancy name for variations on oxygen that are more prone to react with other molecules; these are the “free radicals” you hear so much about on supplement labels and so on). But it gets murky when you consider that other studies show that moderate alcohol use may reduce your risk of heart disease.
The question that every patient is probably asking is: How many of these alcohol-related chemical reactions does it take to kick-start a cancer tumor? How much is too much? What do I do in my day-to-day life?
For some people—those with heart failure, a history of stroke, diabetes, those who take certain medications—drinking can be dangerous. But for the rest of us, I’m afraid scientists still don’t have definite answers. There’s some kind of link, and for that reason, the American Cancer Society recommends that men limit alcoholic drinks to two a day, and women to one.
But we haven’t really figured out exactly how much it too much.
The major reason is that it’s devilishly difficult to do this kind of research. For ethical reasons, you can’t divide patients into two groups, ask one group to binge drink, ask the other to abstain, and then wait to see who dies of cancer.
So alcohol research studies tend to fall into two categories: First, epidemiological analysis of population and mortality databases to try to draw a “big picture” understanding of the relationship between cancer and alcohol. The most recent study falls into this category. But because of the nature of the data—which is usually pulled from giant databases—lots of little questions go unanswered in these studies: For instance, did the people who got cancer binge drink? Did they start drinking young? Did they continue drinking after they got cancer? That kind of fine detail gets lost in the effort to construct a broad picture that can inform public policy.
The second kind of study follows a group of people for a long time, monitoring their habits and health and then seeing what happens to them. This kind of study does get at the fine details of people’s lives, but the data is what scientists call “observational.” That is, researchers “observe” that this percentage of subjects drink, and of those, this percentage end up getting cancer. So in those studies, you can conclude that there’s a link, but these studies don’t prove that the alcohol caused the cancers.
So what do patients do in the meantime? I think we have to proceed with caution, and make up our own minds. If even a small increased risk of cancer death is enough for you to avoid all alcohol, then do that. If, like me, you really enjoy wine and the occasional cocktail, then enjoy those things in moderation. In life, as in research, absolute answers are the rarest of things.