T3+ and T4 rectal cancer patients seem to benefit from the addition of oxaliplatin to the neoadjuvant chemoradiation regimen.

Background: To achieve T-downstaging and better resectability in locally advanced rectal cancer, neoadjuvant radiochemotherapy (RCT) has become the current standard of treatment. A variety of schemes have been used. This study investigates which scheme had the best effect on these parameters.

Methods: Our institution is a referral center for locally advanced rectal cancer. Different neoadjuvant radiochemotherapy regimens were administered: long course radiotherapy (RTH), 5-FU and leucovorin (5FUBolus), a combination of capecitabine and oxaliplatin (CORE), and capecitabine only (CAP). Selection of patients for 1 of the regimens was based on hospital policy rather than patient or tumor characteristics.

Results: The data of 504 consecutive patients (n = 181 T3+, n = 323 T4) without metastatic disease (cM0) who underwent surgery for advanced rectal carcinoma between 1994 and 2010 were reviewed. The RTH, 5FUBolus, CORE, and CAP scheme were administered to 106, 137, 155, and 106 patients, respectively. Odds ratios for downstaging were less effective for RTH, 5FUBolus, and CAP (0.31, 0.44, and 0.31; P < .0001) when compared with the CORE scheme. Odds ratios for a R1 resection (3.74, 1.94, 1.14; P = .003) or CRM+ resection (3.78, 2.73, 1.34; P = .001) were also in favor of the CORE. Hazard ratios for CSS were significantly better for the CORE scheme.

Conclusions: Downstaging with neoadjuvant treatment results in an increased number of radical resections. In our study, the combination of capecitabine and oxaliplatin appears to be the most effective regimen for locally advanced rectal cancer tumors. However, longer follow-up will be necessary to confirm this conclusion.