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.

Dosimetric Evaluation of Organs at Risk From SAVE Protocol.

PURPOSE: The objective of this work was to evaluate dosimetric characteristics to organs at risk (OARs) from short-course adjuvant vaginal cuff brachytherapy (VCB) in early endometrial cancer compared with standard of care (SOC) in a multi-institutional prospective randomized trial. METHODS AND MATERIALS: SAVE (Short Course Adjuvant Vaginal Brachytherapy in Early Endometrial Cancer Compared to Standard of Care) is a prospective, phase 3, multisite randomized trial in which 108 patients requiring VCB were randomized to an experimental short-course arm (11 Gy × 2 fractions [fx] to surface) and SOC arm. Those randomized to the SOC arm were subdivided into treatment groups based on treating physician discretion as follows: 7 Gy × 3 fx to 5 mm, 5 to 5.5 Gy × 4 fx to 5 mm, and 6 Gy × 5 fx to surface. To evaluate doses to OARs of each SAVE cohort, the rectum, bladder, sigmoid, small bowel, and urethra were contoured on planning computed tomography, and doses to OARs were compared by treatment arm. Absolute doses for each OAR and from each fractionation scheme were converted to 2 Gy equivalent dose (EQD23). Each SOC arm was compared with the experimental arm separately using 1-way analysis of variance, followed by pairwise comparisons using Tukey's honestly significant difference test. RESULTS: The experimental arm had significantly lower doses for rectum, bladder, sigmoid, and urethra compared with the 7 Gy × 3 and 5 to 5.5 Gy × 4 fractionation schemes; however, the experimental arm did not differ from the 6 Gy × 5 fractionation scheme. For small bowel doses, none of the SOC fractionation schemes were statistically different than the experimental. The highest EQD23 doses to the examined OARs were observed to come from the most common dose fractionation scheme of 7 Gy × 3 fx. With a short median follow-up of 1 year, there have been no isolated vaginal recurrences. CONCLUSIONS: Experimental short-course VCB of 11 Gy × 2 fx to the surface provides a comparable biologically effective dose to SOC courses. Experimental short-course VCB was found to reduce or be comparable to D2cc and D0.1cc EQD23 doses to rectum, bladder, sigmoid, small bowel, and urethra critical structures. This may translate into a comparable or lower rate of acute and late adverse effects.