Postoperative pelvic radiotherapy with or without elective irradiation of para-aortic nodes and liver in rectal cancer patients. A controlled clinical trial of the EORTC Radiotherapy Group.

Abstract

The purpose of this randomized multicenter study was to assess the impact on disease free and overall survival of low dose irradiation to para-aortic nodes and liver in patients with a locally advanced resected rectal cancer receiving a 50 Gy postoperative pelvic radiotherapy. Main inclusion criteria were: a curative resection for a histologically proved carcinoma of the rectum, Gunderson-Sosin stages B2-B3, C1-C3, age <70 years. The patients were randomized between pelvic irradiation (Lim-XRT): 50 Gy in 25 fractions over 5 weeks and extended irradiation (Ext-XRT): same scheme/doses in the pelvis and extended fields on para-aortic nodes and liver, delivering 25 Gy in 19 fractions over 25 days. From 1983 to 1992, 484 patients were enrolled by 18 EORTC institutions and 29 patients were ineligible. The end-points were local and distant relapses, toxicity and survival. Compliance to treatment: 87.2% in Lim-XRT arm and 71.8% in Ext-XRT arm. Moderate acute hematological and hepatic toxicities were significantly increased in Ext-XRT arm. Among 325 patients at risk, 44 suffered a severe intestinal complication requiring surgery in 29. The 5- and 10-year estimates of disease free survival were respectively 42 and 31% in Lim-XRT arm and 47 and 31% in Ext-XRT arm (ns). The corresponding figures for overall survival were respectively 45 and 40% in Lim-XRT arm and 48 and 37% in Ext-arm (ns). The 10 years estimate of intra-pelvic failures was approximately 30% in both arms. Patients in Ext-arm appeared to have a slight shorter interval free of liver metastases (P=0.047). Low dose irradiation to the para-aortic nodes and liver did not improve survival for patients with resected adenocarcinoma of the rectum.