Preoperative radiotherapy of locally advanced rectal cancer: clinical outcome of short-course and long-course treatment with or without concomitant chemotherapy

Preoperative radiotherapy is considered to be standard treatment for locally advanced rectal cancer. The timing and dosage of radiotherapy with or without preoperative chemotherapy remain controversial issues. The objective of this study was to evaluate relevant clinical outcomes of two preoperative radiotherapy regimens - the short-course and -long-course radiotherapy with or without chemotherapy for patients with locally advanced rectal cancer. 151 patients with stage II-III rectal cancer (103 males and 48 females) treated with preoperative radiotherapy between 01/1999 and 01/2008 were involved in this study. Analysed patterns included sphincter preservation, tumor down-staging, pathological complete remission, frequency of local recurrence, acute and late toxicity, peri-operative complications, overall survival and disease-free survival. Tumor downstaging has been achieved by long-course radiotherapy alone (46%) or in combination with chemotherapy (5-FU or capecitabine, 61%). Pathological complete remission has also been achieved only in the group with long-course radiotherapy (13%). Long-course radiotherapy combined with chemotherapy significantly decreased post treatment local recurrence rates (5% versus 15% in the group after long-course radiotherapy alone, p = 0.0132). Statistically significant difference was confirmed in overall survival of patients treated with long-course radiotherapy combined with chemotherapy vs long-course radiotherapy alone (p = 0.015). Significant difference between the rate of perioperative complications, of acute and late toxicity, 3 and 5 years disease-free survival of treated patients after short-course radiotherapy and long-course radiotherapy was not confirmed. Our findings provide convincing evidence that in comparison to preoperative short-course radiotherapy, the preoperative long-course radiotherapy in combination with chemotherapy is the most effective treatment modality for patients with operable locally advanced rectal cancer in terms downstaging and pathologic complete response. Increase in overall survival time as well as lower local recurrence rate makes this modality superior to other preoperative radiotherapy alternatives.