Pelvic inflammatory disease carries increased risk of epithelial ovarian cancer

Women with a history of pelvic inflammatory disease appear to be at increased risk of epithelial ovarian cancer (EOC), according to a study.

For the study, researchers used data from several Swedish nationwide registers. A total of 15,072 women (mean age 65.5 years) with EOC and 141,322 controls matched based on age and residential district were included in the analysis.

Serous carcinoma was the most common EOC histotype (60.4 percent). Among women diagnosed with EOC between 2015 and 2020, the majority had high-grade serous carcinoma (60.0 percent). Pelvic inflammatory disease was diagnosed in 1.1 percent of women in the EOC group and in 0.9 percent in the control group.

Logistic regression analysis showed an association between previous pelvic inflammatory disease and increased risk of EOC (adjusted odds ratio [aOR], 1.39, 95 percent confidence interval [CI], 1.17–1.66) and serous carcinoma (aOR, 1.46, 95 percent CI, 1.18–1.80) in the entire population.

In the subgroup of women who received an EOC diagnosis in 2015–2020, pelvic inflammatory disease was associated with high-grade serous carcinoma (aOR, 1.43, 95 percent CI, 1.01–2.04). As for other histotypes, the aORs were 0.13 (95 percent CI, 0.02–1.06) for endometrioid, 1.55 (95 percent CI, 0.56–4.29) for mucinous, and 2.30 (95 percent CI, 0.90–5.86) for clear cell carcinoma.

A dose–response relationship was seen, such that the higher the number of pelvic inflammatory disease episodes, the greater the risk of EOC (p<0.001 for trend).