Ovarian cancer risk after salpingectomy for ectopic pregnancy or hydrosalpinx: results of the OCASE nationwide population-based database study

STUDY QUESTION: What is the effect of salpingectomy for ectopic pregnancy or hydrosalpinx at a young age on ovarian cancer risk compared to no salpingectomy for any reason? SUMMARY ANSWER: We found no significant reduction in ovarian cancer risk after salpingectomy for ectopic pregnancy or hydrosalpinx. WHAT IS KNOWN ALREADY: Salpingectomy may reduce ovarian cancer incidence, although the lag-time between intervention and therapeutic effect remains to be elucidated. STUDY DESIGN, SIZE, DURATION: This nationwide population-based database study uses the Dutch pathology database to identify all women who underwent salpingectomy for ectopic pregnancy or hydrosalpinx between January 1990 and December 2012 and compared ovarian cancer incidence to a control group of women who had a benign dermal nevus removed, matched for age at the time and year of procedure. PARTICIPANTS/MATERIALS, SETTING, METHODS: After selection and manual control of intervention and control group, ovarian cancer incidence was recorded. Hazard ratios (HRs) with 95% CI for the development of ovarian cancer were calculated with Cox regression analyses, both unadjusted and adjusted for age. Subgroup analyses were performed to investigate lag time between intervention and protective effect. MAIN RESULTS AND THE ROLE OF CHANCE: In all, 18 96I women were included in the intervention group; 17 106 women had a unilateral salpingectomy and 1855 had a bilateral salpingectomy. The control group consisted of 23 686 women. With 14 ovarian cancer cases in the intervention group, the incidence rate (IR) of ovarian cancer was 5.4 (95% CI 3.1-8.9) per 100 000 person-years. In the control group, there were 24 ovarian cancer cases, resulting in an IR of 7.1 (95% CI 4.7-10.5) per 100 000 person-years (P = 0.34). The age-adjusted HR for ovarian cancer was 0.76 (95% CI 0.39-1.47) after salpingectomy. Unilateral salpingectomy resulted in an age-adjusted HR of 0.81 (95% CI 0.41-1.59) and bilateral salpingectomy resulted in an age-adjusted HR of 0.43 (95% CI 0.06-3.16) based on one case. None of our subgroup analysis for lag-time resulted in a significant difference in ovarian cancer incidence between intervention and control group. The difference in ovarian cancer incidence appeared largest in women with at least 8 years of follow-up (P = 0.08). LIMITATIONS, REASONS FOR CAUTION: Due to the young population, ovarian cancer incidence is low, even at the end of followup. Furthermore, due to the anonymous nature of the pathology registry, we were unable to adjust for confounding factors. WIDER IMPLICATIONS OF THE FINDINGS: Although results did not reach statistical significance, they add to the available data on ovarian cancer incidence after salpingectomy. Our subgroup analysis suggests there may be no benefit in the first years following salpingectomy.