Ovarian cysts may not raise cancer risk in postmenopausal women

Ovarian inclusion cysts found by ultrasonography in postmenopausal women don’t necessarily mean that the women will develop ovarian, breast, or endometrial cancer, a British study reports.

Researchers examined data on more than 202,638 postmenopausal women between 50 and 74 years of age from the UK Collaborative Trial of Ovarian Cancer Screening, about half of whom were randomized to receive regular screening with ultrasound scans. Of the 48,230 women who completed the initial scan, 1,234 women had inclusion cysts and 22,914 had normal ovaries. At average follow-up of 6 years, 4 women with cysts (about 5 in 1,000) and 32 women with normal ovaries (about 1 in 1,000) had developed ovarian cancer. Statistical analysis showed that that chance could easily account for other kinds of cancer. The percentage of women with cysts who developed cancer was similar to the incidence anticipated in the general population of the United Kingdom. The study was published online July 15 in the British Journal of Obstetrics and Gynecology.

“Our data show that ultrasound-detected inclusion cysts in postmenopausal women do not seem to be associated with an increased incidence of primary invasive ovarian or hormone-dependent cancers, such as breast and endometrium,” the authors conclude.

They note that their findings support the recent hypothesis that some primary invasive epithelial ovarian cancers originate in other pelvic organs such as the fallopian tubes or endometrium and “involve the ovary secondarily.” Ultrasound studies of women with simple adnexal cysts also have failed to find a significantly increased risk of ovarian cancer.

Inclusion cysts persisted in 23.2% of women in the study and resolved spontaneously in 40.2%, a finding in line with previous cohort studies of unilocular cysts of all sizes. The researchers note that longer follow-up is necessary to definitively confirm the findings of their study.

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