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Irregular menstrual periods linked to higher ovarian cancer risk

Women who have irregular menstrual periods take note: You may have more than twice the likelihood of getting ovarian cancer than women who get periods every month. That scary news finding was reported this week at the American Association for Cancer Research Conference annual meeting in San Diego.

It worried the heck out of me because I have irregular cycles because of polycystic ovarian syndrome — a hormonal imbalance in the ovaries that occurs in 5 to 10 percent of women — which was also thought to be behind the irregular cycles in most of the 13 percent of women in the study who had a heightened ovarian cancer risk.


Study leader Barbara Cohn, director of the Child Health and Development Studies at the Public Health Institute in Berkeley, Calif., has the condition too, and she designed the research to gain a clearer understanding of the condition's link to ovarian cancer. She and her colleagues examined data from 15,000 pregnant women in their mid-20s who were followed for 50 years after their pregnancy and found that those with irregular cycles (lasting 35 days or longer) were 2.4 times as likely to have been diagnosed with ovarian cancer over that time span.

"These women all got pregnant without fertility drugs, so we can eliminate that as a way to explain the findings," Cohn said. Previous research has suggested that women with PCOS might have a higher ovarian cancer risk because of their more frequent use of drugs to stimulate ovulation.

That said, the latest study doesn't prove that PCOS causes ovarian cancer. It could be that women with the condition have other health factors that put them at increased risk.

More likely, the reason could be because of the higher levels of male hormones associated with PCOS that could be having a harmful effect on the ovary.


Unfortunately, there's no reliable way to screen for ovarian cancer to catch it early. (For this reason, most women get diagnosed too late to be cured.)

Women with BRCA breast cancer gene mutations — that also put them at 40 to 50 times increased risk for ovarian cancer — often consider having their ovaries surgically removed in their 40s, but this certainly wouldn't be warranted in this case, Cohn said.

Instead, she recommends women in their reproductive years speak to their doctors about taking birth control pills, which have been associated with a lower ovarian cancer risk. I've been on the pill for the past 12 years, and I'm hoping it will nullify any increase in risk that I may have.

Deborah Kotz can be reached at dkotz@globe.com. Follow her on Twitter @debkotz2.