Optimal Extent of Prophylactic Irradiation of Paraaortic Lymph Nodes in Patients with Uterine Cervical Cancer

PURPOSE The purpose of this study was to determine optimal extent of prophylactic irradiation of paraaortic lymph nodes (PALN) in patients with uterine cervical cancer who had metastatic pelvic LNs. METHODS AND MATERIALS We retrospectively evaluated 103 patients with cervical cancer and pelvic lymph node metastasis who were treated with prophylactic semi-extended field radiotherapy (SEFRT) between 1990 and 2012. The semi-extended field included PALN below the second lumbar spine with prescribed doses of 45 to 50 Gy. Survival outcomes were calculated using the Kaplan-Meier method, and acute and late toxicities were scored using the Radiation Therapy Oncology Group and European Organisation for Research and Treatment of Cancer toxicity criteria. RESULTS The median follow-up after SEFRT was 61 (range 5-296) months. Overall, 28 patients (27.2%) experienced treatment failures, which were classified as local in 8 patients (7.8%), regional in 8 patients (7.8%), and distant in 13 patients (12.6%). Of the regional failures, only two involved PALN failure around the renal artery or the renal hilum area at the upper margin of the semi-extended field. At 5 years, the overall survival was 82%. Grade 3 or higher acute gastrointestinal and genitourinary toxicities occurred in one and two patients, respectively. As a late toxicity, one patient developed grade 3 small bowel obstruction. CONCLUSION Prophylactic SEFRT provided favorable outcomes with little acute or late gastrointestinal toxicity. For prophylaxis of PALN recurrences, upper part of PALN might not need to be included in patients with uterine cervical cancer and metastatic pelvic LNs.