Is there a link between migraines and breast cancer?

There seems to be, and the good news, such as it is, is that women who get migraines actually seem to be at lower than normal risk of breast cancer. Nobody can quite explain why.

In a study published recently in the journal Cancer Epidemiology, Biomarkers and Prevention, cancer epidemiologist Christopher Li of the Fred Hutchinson Cancer Research Center in Seattle studied the records of nearly 5,000 women with breast cancer and roughly the same number without. He found that women with a history of migraine headaches had a 26 percent lower risk of breast cancer. The study was a follow-up to a preliminary study by Li that produced similar findings last year.

“The data are really quite consistent,” said Li. The link, he said, is probably hormonal since it’s well known that some breast cancers are driven by estrogen and many women with migraines tend to get the headaches when estrogen levels fall, such as just before a menstrual period. “Women with migraines suffer quite a bit, so the silver lining here is that there is a reduced risk of breast cancer,” he said. “This is important because there are not that many factors that reduce the risk of breast cancer and here is a new one.”

No one, of course, is suggesting that migraines are a good thing, even if they are linked to lower breast cancer risk. Nor is the putative hormonal link between migraines and breast cancer well established. “The association is an interesting one that I cannot explain easily based on what I know about migraine pathophysiology,” said Dr. Michael A. Moskowitz, a neurologist at Massachusetts General Hospital. Both migraines and breast cancer “are relatively common and in some way, ovarian hormones are probably implicated. I doubt a simple explanation awaits.”

There are no clear implications for treatment from this finding. But at the very least, women who get migraines may get some comfort from knowing that their headaches may carry a medical benefit.