Which patients benefit from preoperative chemoradiotherapy for intermediate staged rectal cancer?

Background: The aim of this study was to identify subgroups that benefit from preoperative or postoperative chemoradiotherapy (CRT) for rectal cancer of intermediate stage. Patients and Methods: Between 1999 and 2004, 118 and 177 patients matched with respect to clinical T stage, circumferential tumor extent (= 60% / > 60%), lymph node metastasis, and lymph node size (< 1 cm / = 1 cm), were allocated to preoperative CRT and postoperative CRT, respectively. In preoperative CRT, a total of 45 Gy was delivered with chemotherapy, and then surgery followed. In postoperative CRT, 45-51 Gy was delivered with chemotherapy following primary surgery. Results: Local recurrence, distant metastasis, disease-free survival, and disease-specific survival were not different between the two schemes. For a circumferential tumor extent of = 60%, local recurrence in preoperative CRT (3.6%) was lower than in postoperative CRT (11.9%) (p = 0.084, hazard ratio (HR) = 0.274, 95% confidence interval (CI) = 0.058-1.032). For a tumor located < 5cm from the anal verge, distant metastasis in preoperative CRT (18.9%) was lower than in postoperative CRT (34.4%) (p = 0.061, HR = 0.444, 95% CI = 0.188- 1.047), and 5-year disease-free survival rates in preoperative and postoperative CRT were 72.0 and 59.0%, respectively (p = 0.078). Conclusions: Our findings suggest that preoperative CRT might be appropriate in rectal cancer involving the limited circumferential lumen and located in the low rectum. However, further prospective studies are required.