Abstract 3956
Background
Postoperative radiotherapy is still recommended for stage II/III rectal cancer after defnitive surgery who did not receive preoperative chemoradiotherapy. This phase III study aims to explore the role of oxaliplatin combined with postoperative concurrent capecitabine and radiotherapy for stage II/III rectal cancer.
Methods
Patients with pathologically confirmed stage II/III rectal cancer were randomized (1:1) to either radiotherapy with concurrent capecitabine (Cap-RT group) or with capecitabine and oxaliplatin (Capox-RT group). Radiotherapy consisted of 45-50.4 Gy in 25-28 fractions. In the Cap-RT group, concurrent chemotherapy consisted of two cycles of oral capecitabine (1,600 mg/m2) on days 1–14 and 22–35. The Capox-RT group received radiotherapy concurrent with oral capecitabine (1,300 mg/m2) on days 1–14 and 22–35, and a 2-h infusion of oxaliplatin (60 mg/m2) on weeks 1, 2, 4, and 5. Following 4 weeks of completing chemoradiation, 4-12 cycles of fluorouracil based adjuvant chemotherapy was delivered. The primary endpoint was 3-year disease-free survival rate (DFS).
Results
Between April 1, 2008 and September 30, 2015, we enrolled 589 participants from nine centers in China. Of these participants recruited, 294 were in the Cap-RT group and 295 in the Capox-RT group. Baseline characteristics were well balanced between two groups. The 3-year and 5-year DFS rate was 73.7% and 69.7% in the Capox-RT group and 76.1% and 71.2% in the Cap-RT group (p = 0.546), respectively. No significant difference was observed in overall survival, cumulative incidence of local recurrence or distant metastasis between two groups (p > 0.05). More grade 3-4 acute toxicity was observed in the Capox-RT group than in the Cap-RT group, but not significantly (47.1% vs. 39.5%, p = 0.065). In N2 subgroup analysis, DFS rate in Capox-RT group was significantly higher than Cap-RT group (p = 0.045).
Conclusions
In stage II/III rectal cancer, either radiotherapy with concurrent capecitabine or capecitabine and oxaliplatin are equally beneficial in long-term survival. N2 subsets of patients may benefit from intensive concurrent chemotherapy regimen.
Clinical trial identification
NCT00714077.
Legal entity responsible for the study
Jing Jin.
Funding
Chinese National Nature Science Funding.
Editorial Acknowledgement
Disclosure
All authors have declared no conflicts of interest.