Pelvic inflammatory disease and risk of ovarian cancer.

We analyzed the association between history of pelvic inflammatory disease (PID) and the risk of subsequent epithelial ovarian cancer, using data from a large case-control study conducted between 1983-1991 in Italy. Data were collected from a network of hospitals, including the main teaching and general hospitals in the greater Milan area, Northern Italy. The cases studied were 971 women below the age of 75 years (median age, 54 years) with histologically confirmed epithelial ovarian cancer, diagnosed within 1 year before the interview. Control subjects were 2758 women admitted to the same hospitals where cases were identified for acute, nonmalignant, nonhormone-related conditions, who had not undergone bilateral oophorectomy. The median age of the control group was 52 years (range, 23-74). A total of 14 (1.4%) cases and 72 (2.6%) controls reported a history of PID/ salpingitis, the corresponding multivariate relative risk being 0.7 (95% confidence interval, 0.4-1.3). A separate analysis of the association between history of PID/salpingitis and risk of ovarian cancer in strata of parity and education confirmed the results based on the whole series. In conclusion, although based on limited numbers of cases and controls with PID, this studies was able to exclude, at the conventional 95% confidence limit, an increased risk of ovarian cancer of over 30% in women with previous PID in this population.