Is Prophylactic Radiotherapy to the Lymphatic Drainage Area Necessary for Patients With Stage III Ovarian Cancer After Chemotherapy Following Surgery?

Abstract

For patients with stage III epithelial ovarian cancer, there are limited studies on the effects of postoperative adjuvant radiotherapy (RT). Here we assessed the therapeutic efficacy and toxicity of postoperative radiotherapy to the abdominal and pelvic lymphatic drainage area for stage III epithelial ovarian cancer patients, who had all received surgery and chemotherapy (CT). We retrospectively collected patients with stage III epithelial ovarian cancer after cytoreductive surgery (CRS) and full-course adjuvant CT. The chemoradiotherapy (CRT) group patients were treated with intensity modulated radiotherapy (IMRT) to the abdominal and pelvic lymphatic drainage area in our hospital between 2010 and 2020. A propensity score matching analysis was conducted to compare the results between the CRT and CT groups. Kaplan-Meier analysis estimated overall survival (OS), disease-free survival (DFS), and local control (LC) rates. The log-rank test determined the significance of prognostic factors. A total of 132 patients with median follow-up of 73.9 months (9.1-137.7 months) were included (44 and 88 for the CRT and RT groups, retrospectively). The baseline characteristics of age, histology, level of CA12-5, surgical staging, residual tumour, courses of adjuvant CT, and courses to reduce CA12-5 to normal were all balanced. The median DFS time, 5-year OS, and local recurrence free survival (LRFS) were 100.0 months vs 25.9 months (P = .020), 69.2% vs 49.9% (P = .002), and 85.9% vs 50.5% (P = .020), respectively. The CRT group mainly presented with acute haematological toxicities, with no statistically significant difference compared with grade III intestinal adverse effects (3/44 vs 6/88, P = .480). This report demonstrates that long-term DFS could be achieved in stage III epithelial ovarian cancer patients treated with IMRT preventive radiation to the abdominal and pelvic lymphatic area. Compared with the CT group, DFS and OS were significantly prolonged and adverse effects were acceptable.