NEW YORK (Reuters Health) – New research suggests that regardless of how hormone therapy is given, it increases the risk of ovarian cancer.

“Our study suggests an increased risk of ovarian cancer with both estrogen therapy and combined hormone therapy, with little influence of different regimens, progestin types, routes of administration, length of use, and different doses,” Dr. Lina Steinrud Morch, from Rigshospitalet, Copenhagen, Denmark, and colleagues conclude.

Their findings, reported in the Journal of the American Medical Association for July 15, stem from a prospective cohort study featuring all Danish women who were 50 to 79 years of age from 1995 to 2005. Included in the analysis were 909,946 women without hormone-sensitive cancer or bilateral oophorectomy at baseline.

During a mean follow-up period of 8.0 years, 3068 ovarian cancers were detected, including 2681 epithelial malignancies.

Current hormone users were 38% and 44% more likely to develop all ovarian cancers and epithelial ovarian cancers, respectively, than were never users, the report indicates. The risk decreased with time since use.

In terms of absolute risk, the incidence rate of ovarian cancer in current hormone users was 0.52 per 1000 years versus 0.40 per 1000 years in never users. This translates into roughly 1 extra case of ovarian cancer per 8300 women who use hormone therapy each year, the authors state.

As noted, the link between hormone therapy and ovarian cancer was apparent regardless of the type of therapy used and the duration of use.

“The risk of ovarian cancer,” the authors conclude, “is one of several factors to take into account when assessing the risks and benefits of hormone use.”

Reference:
JAMA 2009;302:298-305.