Association of pelvic inflammatory disease (PID) with ovarian cancer: a nationwide population-based retrospective cohort study from Taiwan Original paper

What was studied?

This study examined the association between pelvic inflammatory disease (PID) and the subsequent risk of ovarian cancer in women. Using data from Taiwan’s National Health Insurance Research Database (NHIRD), the researchers conducted a population-based, retrospective cohort study. The study focused on women diagnosed with PID between 2000 and 2012 and compared their risk of developing ovarian cancer to that of women without PID. The study used Cox proportional hazards regression models to analyze the association, adjusting for potential confounders such as age, comorbidities, and income.

Who was studied?

The study included women aged 18 years and older who were diagnosed with PID, as indicated by the ICD-9-CM code for PID between 2000 and 2012. Each woman with PID was matched with two women without PID based on age and the date of entry into the NHIRD. The study followed both cohorts until they either developed ovarian cancer, withdrew from the National Health Insurance program, died, or the study period ended in December 2012.

What were the most important findings?

The study found a significant association between PID and an increased risk of developing ovarian cancer. Over an approximate 10-year follow-up period, women with a history of PID had a 1.49-fold higher risk of ovarian cancer compared to those without PID. The incidence rate of ovarian cancer in women with PID was 0.27 per 1,000 person-years, compared to 0.16 per 1,000 person-years in the control group (P <0.001). The study also identified that women aged 40 years and older with PID were at a higher risk than younger women. The study highlighted several comorbidities associated with an increased risk of ovarian cancer in the PID cohort, including endometriosis, infertility, and a history of uterine or breast cancer. These comorbidities were more prevalent in the PID group than in controls. The findings suggested that PID is not only a risk factor for infertility but also for ovarian cancer, possibly due to chronic inflammation that may promote carcinogenesis.

What are the greatest implications of this study?

This study has significant clinical implications, particularly in identifying women at high risk for ovarian cancer. Given the observed association between PID and increased ovarian cancer risk, healthcare providers should carefully monitor women with a history of PID, especially those over 40 years of age. This could include earlier and more frequent screenings for ovarian cancer. The study suggests that PID may serve as a sentinel event for ovarian cancer, with chronic inflammation potentially contributing to cancer development. The findings underscore the need for targeted preventive measures and early detection strategies, especially in populations with known PID risk factors. Further research in different populations is necessary to confirm these results and refine prevention guidelines.