Risk of secondary malignancies in ovarian cancer survivors: 52,680 patients analyzed with over 40 years of follow-up.

OBJECTIVE: Survivors of ovarian cancer are at risk of developing a secondary malignancy (SM). We sought to evaluate the risk of developing SM, stratified by treatment modality. METHODS: Standardized incidence ratios (SIR, observed-to-expected [O/E] ratio) were assessed in 52,680 patients diagnosed with ovarian cancer between 1975 and 2016 in the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. RESULTS: Of the 52,680 patients, 3366 patients (6.4%) developed SM, which was more than the endemic rate (O/E 1.13; p < .05). Patients who received any radiation (RT) had an increased risk of overall SM compared to those who didn't (O/E 1.42 vs 1.11; p < .05), and specifically, in the bladder (O/E 2.81). Patients who received any chemotherapy (CT) had an increased risk of leukemia (O/E 3.06), and a similar risk of overall SM compared to those not treated with CT (O/E 1.11 vs 1.14; p < .05). The excess risk of developing a solid tumor SM was greatest at latencies of 10-20 years. Patients younger than 50 had the highest risk of developing SM. Non-White patients had a higher risk of SM compared to White patients. CONCLUSIONS: This is the largest study to examine the risk of SM in patients with ovarian cancer and has the longest follow-up. Risk of SM was increased after ovarian cancer and varied with treatment modality, race, latency, and age. These results may help inform SM screening protocols for women diagnosed with ovarian cancer.