Irregular Periods: Risk Factor for Ovarian Cancer?
Preliminary finding might eventually offer clue to which women would benefit from early screening
An irregular menstrual cycle was defined as longer than 35 days even if it was regular, a cycle that was unpredictable from month to month (and the woman wasn't in perimenopause when unpredictable cycles are normal), or if a woman didn't ovulate, Cohn said. The women were around age 26 when they reported having irregular periods.
Although none of the women was diagnosed with polycystic ovary syndrome when the study began because the disease wasn't really recognized at the time, it's likely that at least some of them had the hormonal disorder, Cohn said.
Polycystic ovarian syndrome is a common cause of irregular periods, but it's possible that other abnormalities associated with the disorder might also explain the study findings, she said.
During the study, 103 women developed ovarian cancer, 20 of whom had irregular periods, said Cohn. And 65 died of ovarian cancer, 17 with irregular menstrual cycles. The average age of ovarian cancer death was about 69.
Women with irregular periods had a 2.4 times higher risk of ovarian cancer death than women who had normal cycles, the researchers concluded. In addition, women who had a first-degree relative (mother, sister or daughter) with ovarian cancer, a known risk factor for the disease, had almost three times the risk of death from ovarian cancer, said Cohn.
A lot of biological factors increase a person's risk of ovarian cancer, said Dr. David Fishman, director of the Mount Sinai Ovarian Cancer Risk Assessment Program in New York City.
"This study's findings are an interesting observation, but it's not cause and effect, and I don't want women to be afraid," Fishman said. "Menstrual irregularities are very common, and most women with menstrual irregularities won't have ovarian cancer."
For women who have menstrual irregularities, this study reinforces the benefit of birth control pills to reduce the risk of ovarian cancer, Fishman added.
Any woman who is concerned should talk to her doctor, he said. Her physician can let her know if she's at an increased risk of developing ovarian cancer.
The study findings were scheduled for presentation Wednesday at the American Association for Cancer Research annual meeting in San Diego.
Research presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.