Endometriosis Ups Risk of Other Cancers
Study Shows Higher Rates of 4 Cancers, Lower Risk of Cervical Tumors
What Is Endometriosis? continued...
"For one thing, there's been surprisingly little epidemiologic study done on endometriosis, even though it's a condition that afflicts a lot of women," says Thun, who was not involved in the study.
"But from a scientific point of view, one of the interesting things about endometriosis is that it is non-malignant tissue than can invade other tissue -- it's tissue that is benign but behaves in a malignant way. Another interesting thing is that many aspects of endometriosis are like those of chronic inflammation, and there's a big interest in the relation of chronic inflammation and cancer."
The finding didn't surprise Roberta B. Ness, MD, MPH, of the University of Pittsburgh Graduate School of Public Health. Last year, she presented her own research at the annual meeting of the Society of Gynecologic Oncologists suggesting that women with endometriosis did have an increased risk of ovarian cancer.
"This finding is not surprising at all," Ness tells WebMD. "The data continues to be very consistent: Overall, there's an increased risk of ovarian cancer in women who have endometriosis. And for women with longstanding endometriosis that is specifically affecting the ovaries -- that is, the abnormal cells are found on the ovarian surface -- the risk is even higher."
Because Berglund's study adds to previous evidence that hysterectomy seems to protect women with endometriosis against ovarian cancer, "I would say the more critical take-home message is that women who had hysterectomy had a reduction in (ovarian cancer) risk," says Ness, who is currently researching how women with endometriosis can reduce their cancer risk.
"We know there are things to reduce risk in women -- oral contraceptives, having babies, tubal ligation. What we don't know is, specifically, are these risks also preventative in women who have endometriosis?"