Abdominopelvic Lymphatic Drainage Area Irradiation for Consolidative Radiotherapy of Advanced Ovarian Carcinoma: Analysis of Clinical Application Efficacy and Dosimetric Verification

Background: The aim of the study was to evaluate the efficacy of abdominopelvic lymphatic drainage area irradiation (APLN), instead of whole abdominal radiotherapy (WART), in the consolidative radiotherapy of advanced ovarian carcinoma patients. Methods: We conducted a retrospective analysis collecting 99 patients with locally advanced ovarian cancer treated by APLN with 45 - 50 Gy/25- 28 fractions/5-7#, instead of WART. We evaluated the clinical outcome of APLN. Five patients were selected for dosimetric verifications verses WART (30 Gy/20 fractions). The normal tissue complication probability (NTCP) was calculated for the two treatment methods. Results: The mean follow-up time was 64.10 months (5.5 - 113.2 months), after APLN consolidative radiotherapy, 1-, 3-, and 5-year overall survival (OS) was 87.9%, 81.3%, and 61.5%, median diseasefree survival (DFS) was 40.8 months, 5-year local recurrence free survival (LRFS) was 75.9%, and 5-year distant metastasis free survival (DMFS) was 49.2%. One patient died due to intestinal perforation. Local recurrence in the area between WART and APLN was rare (3/99 patients). The number of surgical procedures < 2 was an independent risk factor for LRFS (P = 0.023). Dosimetric comparison showed that comparing with WART, APLN significantly reduced the organ at risk (OAR) dose: 25.37 +/- 3.63 Gy (25%) for liver, 8.77 +/- 5.03 Gy (25%) for kidney, 8.14 +/- 1.51 Gy (25%) for small intestine, etc. NTCP was reduced by 0.04-1.04% for liver, kidney, and small intestine. Conclusion: For consolidative radiotherapy in locally advanced ovarian cancer, APLN (intensity-modulated radiotherapy 45 - 50 Gy/25 - 28 fractions) could be an alternative to WART, resulting in excellent LRFS and DFS, with acceptable toxicities, comparing with previous literature reports. Dosimetric analysis also showed the benefits of APLN in NTCP.