A history of pelvic inflammatory disease (PID) doubles the risk of ovarian cancer, a study suggests, raising hopes that many women could be diagnosed and treated for the deadly cancer earlier.

The study authors, writing in the Lancet Oncology, noted that ovarian cancer was the second most common gynaecological cancer but had the highest mortality, largely because it was often diagnosed at a late stage.

Based on their findings, they suggested PID might be “a useful marker for ovarian cancer" allowing earlier treatment.

Their study included data from 68,000 Taiwanese women aged between 13 and 65 years with a diagnosis of PID confirmed by multiple episodes, and 136,000 matched controls.

Among these, 90 developed ovarian cancer during the three-year follow-up period (42 PID patients and 48 controls).

Compared with controls, the adjusted hazard ratio for ovarian cancer was 1.92 among patients with PID (95 per cent CI 1.27-2.92), rising to 2.46 (1.48-4.09) for those with at least five episodes of PID.

Women aged 35 years or younger who had PID were at slightly higher risk of developing ovarian cancer "in line with previous research, the authors noted.
"Whether pelvic inflammation itself accelerates the growth of ovarian cancers or affects cancer-cell differentiation in ways that adversely alter prognosis needs to be investigated,"they wrote.

They recommended chronic diseases associated with PID, such as diabetes mellitus, endometriosis and chronic liver disease, “should not be neglected by clinicians"

The study also found an unexpected link between oral contraceptive use and increased risk of ovarian cancer - possibly due to higher sexual activity among users.

An accompanying comment described the study as “important and timely" contributing to the emerging picture of this complex disease"

"Methods for the prevention, timely diagnosis, and treatment of PID could be essential to prevent ovarian cancer in a subgroup of patients," it said.