Adjuvant chemoradiation plus intraoperative radiotherapy versus adjuvant chemoradiation alone in patients with locally advanced rectal cancer.

OBJECTIVES: To document the efficacy of intraoperative radiotherapy (IORT) followed by adjuvant chemoradiation in the management of locally advanced rectal cancer. MATERIALS AND METHODS: A total of 148 patients with pT4N0/T1-4N+ rectal adenocarcinoma were enrolled. Seventy-seven patients received total mesorectal excision surgery followed by adjuvant chemoradiation alone, 71 patients received total mesorectal excision surgery followed by IORT (range, 10 to 20 Gy) and adjuvant chemoradiation. RESULTS: The 5-year local control (LC) and disease-free survival were 79.2% versus 89.7% (P=0.032), 58.5% versus 69.0% (P=0.049) for external-beam radiation (EBRT) and IORT+EBRT groups, respectively. Multivariate analysis revealed that adjuvant IORT has a trend toward improvement of LC (P=0.079); 5 (3%) patients (EBRT n=2; IORT n=3) experienced incomplete intestinal obstruction and 3 patients had chronic diarrhea. There was no clinically relevant neuropathy or sacral osteoradionecrosis. Hydronephrosis occurred in 13 patients (EBRT n=8; IORT+EBRT n=5), 8 of whom had documented concomitant disease recurrence. CONCLUSIONS: For patients with locally advanced rectal cancer, higher radiation dose may contribute to the improvement of both LC and disease-free survival, without significantly increasing the incidence of acute and long-term complications compared with adjuvant chemoradiotherapy alone.