Is preoperative chemoradiotherapy warranted in magnetic resonance imaging-based clinically T3N0 rectal cancer?

Purpose: Preoperative chemoradiotherapy (PCRT) has been widely adopted. However, benefit of PCRT for patients with clinically T3N0 (cT3N0) rectal cancer is doubtful. We analyzed oncologic outcome in patients with magnetic resonance image (MRI) staged cT3N0 rectal cancer according to receipt of PCRT. Methods: Between January 2006 and December 2010, one hundred twenty four patients were MRI-based T3N0 rectal cancer. In patients who received PCRT the median dose of given radiotherapy was 5,040 Gy, and either 5-fluorouracil/leucovorin, capecitabine or S-1/oxaliplatin was delivered. The 3-year disease free survival rate (DFS) and sphincter preservation were compared. Results: Sixty four patients received and sixty patients did not receive PCRT. Rate of complete remission was obtained in 17.2% of PCRT group. Sphincter-preserving surgery was performed in 79.7% of PCRT group and 88.3% of non-PCRT group (P=0.194). In patients with low-lying rectal cancer, sphincter-preservation was also not different; PCRT 70.5% and non-PCRT 66.7% (P=0.761). Overall recurrence occurred in 21.9% in PCRT group and 15.0% in non-PCRT group (P=0.327). Three-year DFS was comparable between PCRT (76.5%) and non-PCRT group (79.7%) (P=0.330). Conclusion: Preoperative chemoradiotherapy in MRI-based cT3N0 rectal cancer had no benefit on sphincter preservation and did not improve DFS. Therefore, the routine use of PCRT in cT3N0 rectal cancer should not be warranted.