Fluorouracil-based preoperative chemoradiotherapy with or without oxaliplatin for stage II/III rectal cancer: a 3-year follow-up study.

backgroundFluorouracil-based preoperative chemoradiotherapy has become the standard treatment for stage II/III rectal cancer. In order to improve the overall survival (OS) and disease-free survival (DFS), we added oxaliplatin to the standard treatment, and compared the effectiveness of these two treatment patterns.

methodsA total of 206 patients enrolled in the prospective study had histologically confirmed rectal cancer of clinical stage II/III during July 2007 to July 2010. They were randomized into the experimental group received oxaliplatin and capecitabine in combination with radiotherapy, and the control group received capecitabine in combination with radiotherapy. All patients received surgery in 6-10 weeks after chemoradiotherapy and adjuvant chemotherapy with mFOLFOX6. The primary endpoints were DFS and OS, and the secondary endpoints included toxicity, compliance, and histopathological response.

resultsThe 3-year OS in the experimental group and the control group was 90.29% vs. 86.41% (P>0.05), and the 3-year DFS was 80.58% vs. 69.90% (P>0.05). The pathological complete remission (pCR) rates were 23.30% and 19.42%, respectively (P=0.497). The 3-year local recurrence rates were 4.85% vs. 5.83% (P=0.694), and the 3-year distant metastasis rates were 16.50% and 28.16%, respectively (P=0.045). There were no significant differences in most grade 3-4 toxicities between two groups, however, grade 3-4 diarrhea occurred in 16.50% (17/103) of the experimental group, compared with 6.80% (7/103) of the control group (P=0.030). Also, the total grade 3-4 acute toxicity showed a significant difference (10.68% vs. 21.36%, P=0.037).

conclusionsThe experimental treatment did not lead significantly improved OS and DFS, and thus longer follow-up is warranted for our patient cohort. Adding oxaliplatin to capecitabine-based preoperative chemoradiotherapy can significantly reduce metastasis, but has only minimal impact on local recurrence. Although grade 3-4 toxicity rate increased (primarily gastrointestinal toxicity), patients can stand to be followed up with allopathic treatment.