Link Between Hormone Therapy and Ovarian Cancer Examined in Study

The findings of a new study suggest that the side effects of hormone replacement therapy (HRT) may increase the risk of ovarian cancer.

Researchers from the U.K. warm that that one out of every 1,000 women taking HRT over the long-term may develop ovarian cancer, and one out of 1,700 may die from it.

The study was published online by the medical journal The Lancet on February 12, examining datasets from 52 epidemiological studies involving 12,110 postmenopausal women who developed ovarian cancer, 55% of whom had been placed on HRT, such as Prempro. The research comes as a result of an analysis by the Collaborative Group on Epidemiological Studies on Ovarian Cancer.

Researchers found that the risk of ovarian cancer was increased by up to 43% and that risks were similar in European and American studies. The risk declined the longer the user had been off the therapy.

“The increased risk may well be largely or wholly causal; if it is, women who use hormone therapy for 5 years from around age 50 years have about one extra ovarian cancer per 1,000 users,” the researchers concluded, adding, “and, if its prognosis is typical, about one extra ovarian cancer death per 1,700 users.”

Hormone Therapy Side Effects

The findings come less than a month after another study was published in the Canadian Medical Association Journal, indicating that women taking HRT drugs such as Prempro and Premarin face a significantly increased risk of pancreatitis. That study found that women who used systemic therapy or who took the drugs for more than a decade faced the highest risks.

Previously, hormone replacement therapy has been the subject of thousands of failure-to-warn lawsuits filed by women who developed breast cancer following use of the medications. The Prempro lawsuits alleged that the drug makers knew or should have known about the risk of cancer, but withheld information from consumers and the medical community.

A 2002 study by the Women’s Health Initiative first warned about the link between breast cancer and hormone replacement therapy.

More recently, in 2012, a study using data from the Nurse’s Health Study, found an 88% increase in the risk of breast cancer for women who underwent HRT over a period of 10-15 years. The risk doubled if the women used HRT for 15 to 20 years.

Pfizer agreed to pay out about $1.2 billion to settle 10,000 HRT breast cancer lawsuits in 2012, after several juries nationwide have awarded multi-million dollar compensatory damage awards to plaintiffs diagnosed with breast cancer after HRT use, including a number of cases that included punitive damage awards after juries found that drug makers intentionally hid the risks associated with the medications.