No significant increase in ovarian Ca risk with HT: new WHI analysis: investigators say combo HT's bone benefits don't outweigh therapy's overall risks.

Two new Women's Health Initiative final analyses have concluded that combination hormone therapy may result in a slight but insignificant increase in ovarian cancer and that, despite offering fracture protection to healthy postmenopausal women, the therapy's overall risks still outweigh its benefits for bone in the study population.

One of the analyses showed a 1.58-fold increase in ovarian cancers with hormone therapy (HT), compared with placebo, but this increase was not statistically significant, because of the small number of women who developed the rare cancer: 20 cases in the HT group vs. 12 in the placebo group after 5.6 years of follow-up (JAMA 290[13]:1739-48, 2003).

Ovarian cancer deaths were also increased in the HT group, compared with the placebo group (9 vs. 3).

"The number of gynecologic cancers observed was small, yielding wide confidence intervals for the overall effects," said Garnet L. Anderson, Ph.D., of the Fred Hutchinson Cancer Research Center in Seattle, and her associates.

"The low rates of gynecologic cancers in the population and the limited precision in the estimated effects from this trial suggest that the results should not have an appreciable influence on most women's decision-making when seeking relief for moderate to severe vasomotor symptoms."

Although there was a slightly increased incidence rate in the treatment group compared with the placebo group, the observed incidence of ovarian cancer, 34 per 100,000 person-years in the entire study group, was lower than the expected population-based rate of 45 per 100,000 person-years.

Despite the small numbers, the trend is worrisome and needs confirmation, the investigators said.