['This randomized phase II trial investigated the efficacy and safety of capecitabine/oxaliplatin (CapOx) plus bevacizumab and dose-modified capecitabine/irinotecan (mCapIri) plus bevacizumab as first-line therapy in patients with metastatic colorectal cancer (mCRC).', 'Patients received bevacizumab 7.5 mg/kg with oxaliplatin 130 mg/m(2)/day 1 plus capecitabine 1000 mg/m(2) bid/days 1-14 or with irinotecan 200 mg/m(2)/day 1 plus capecitabine 800 mg/m(2) bid/days 1-14 both every 21 days. The primary end point was 6 months progression-free survival (PFS).', 'A total of 255 patients were enrolled. The intent-to-treat population comprised 247 patients (CapOx-bevacizumab: n = 127; mCapIri-bevacizumab: n = 120). The six-month PFS rates were 76% (95% CI, 69%-84%) and 84% (95% CI, 77%-90%). Median PFS and OS were 10.4 months (95% CI, 9.0-12.0) and 24.4 months (95% CI, 19.3-30.7) with CapOx-bevacizumab, and 12.1 months (95% CI, 10.8-13.2) and 25.5 months (95% CI, 21.0-31.0) with mCapIri-bevacizumab. Grade 3/4 diarrhea as predominant toxic effect occurred in 22% of patients with CapOx-bevacizumab and in 16% with mCapIri-bevacizumab.'] Is capecitabine/irinotecan or capecitabine/oxaliplatin in combination with bevacizumab effective and safe as first-line therapy for metastatic colorectal cancer : a randomized phase II study of the AIO colorectal study group?