Results of a nationwide study of Taiwanese women show that those diagnosed with pelvic inflammatory disease had nearly double the risk for developing ovarian cancer within 3 years. The risk was even greater for women diagnosed with at least five episodes of the pelvic condition.

Using the Longitudinal Health Insurance Database 2005, researchers collected data on 67,936 females aged 13 to 65 years who had been diagnosed with pelvic inflammatory disease in 2004 or 2005. All patients were followed from the date of entry into the database until the end of 2006 or a diagnosis of ovarian cancer, whichever came first.
For the control group, patients were matched by age and year of entry into the database.

Forty-two women in the pelvic inflammatory disease group developed ovarian cancer, for an incidence of 2.78/10,000 person-years, compared with 48 women in the control group (n=135,872), for an incidence of 1.44/10,000 person-years.

The adjusted HR for ovarian cancer in patients with pelvic inflammatory disease was 1.92 (95% CI, 1.27-2.92) compared with controls. The HR increased to 2.46 (95% CI, 1.48-4.09) for women diagnosed with at least five episodes of pelvic inflammatory disease.

Women aged 35 years or younger with pelvic inflammatory disease had a slightly greater risk (HR=2.23; 95% CI, 1.02-4.79) compared with older women (HR=1.82; 95% CI, 1.10-3.04).