Purpose: The aim of the study was to examine the potential association between a history of pelvic inflammatory disease (PID) and risk of epithelial ovarian cancer or ovarian borderline tumors.
Methods: In a population-based case-control study in Denmark, we included 554 women with invasive ovarian cancer, 202 with ovarian borderline tumors, and 1,564 controls aged 35-79 years. The analyses were performed in multiple logistic regression models.
Results: We found a significantly increased risk of ovarian borderline tumors among women with a history of PID (OR = 1.50; 95% CI 1.08-2.08) but no apparent association between PID and risk of invasive ovarian cancer (OR = 0.83; 95% CI 0.65-1.05). We found no effect of age at time of first PID or time since first PID on the risk for either condition.
Conclusion: Our results suggest that a history of PID is associated with an increased risk of ovarian borderline tumors, which may support the hypothesis that inflammation is an etiological factor. The lack of an association between previous PID and invasive ovarian cancer may indicate an etiological difference between ovarian borderline tumors and invasive ovarian cancer. However, an important limitation of the study is the use of self-reported PID.