Comparison of acute toxicities between two postoperative concurrent chemoradiotherapy regimens of capecitabine with or without oxaliplatin in patients with stage II and III rectal cancer

Objective: To compare the acute toxicities between two prospective, non-randomize phase II trials on adjuvant radiochemotherapy of capecitabine with or without oxaliplatin in patients with stage II and III rectal cancer. Methods: From March 2005 to November 2007, based on two fulfilled phase I studies, two phase II trials were launched respectively to further observe the tolerance and toxicity. In one trial, 118 patients were treated with concurrent capecitabine and radiotherapy (Cap-CRT trial), with radio- therapy of DT50 Gy/25 F/5 wks to the pelvis, and capecitabine at a dose of 1600 mg/m2/d (d1-d14,3 weeks per cycle). In the other trial, 90 patients received concurrent oxaliplatin,capecitabine and radiotherapy(Cap-Oxa-CRT trial), with the same radiotherapy schedule, while oxaliplatin at a dose of 70 mg/m2 (d1, d8) and capecitabine of 1300 mg/m2/d(d1-d14,3 weeks per cycle). Results: There was no significant difference in the delay of radiotherapy (10.2% vs 6.7%, χ2=0.80, P=0.460) or chemotherapy (9.3% vs 19.1%, χ2=4.80, P=0.090) between Cap-CRT and Cap-Oxa-CRT trials. Grade 1-4 leukopenia, diarrhea and nausea were the most common acute side-effects in the both trials, accounting for 70.2%, 65.9% and 42.3%, respectively. When comparing with Cap-CRT trial, Cap-Oxa-CRT trial had significantly more grade 1-4 non-hemotological toxicities, mainly in GI, including nausea (68.9% vs 22.0%, χ2=46.90, P= 0.000), diarrhea (76.7% vs 57.6%, χ2=13.50, P=0.009), fatigue (47.8% vs 13.7%, χ2=18.90, P=0.000), hand-foot syndrome (14.4% vs 4.2%, χ2=7.10, P=0.029), and inappetence (50.0% vs. 27.9%, χ2=25.70,P=0.000), but not in hematological toxities of leukopenia, anemia or thrombocytopenia. Of all the patients, grade 3 and grade 4 toxicities were diarrhea (24.0% and 1.0%), leukopenia(4.3% and 0.0% ), radiation-induced dermatitis (3.8% and 0.0%), cramping abdominal pain (1.0% and 0.0%) and fatigue(0.5% and 0.0% ). Only grade 3 and 4 diarrhea was significantly more in Cap-Oxa-CRT trial than in Cap-CRT trial(33.0% vs 18.6%, χ2=5.90, P=0.023). Conclusions: For patients with stage II and III rectal cancer, both the postoperative concurrent radiochemotherapy regimens are tolerable, though Cap-Oxa-CRT trial has more grade 3 and 4 diarrhea. (authors)