Preoperative treatment with capecitabine, bevacizumab and radiotherapy for primary locally advanced rectal cancer - A two stage phase II clinical trial

Background and purpose: The aim of this single-arm multicenter phase II clinical trial was to assess the feasibility and tolerability of preoperative radiotherapy and simultaneous capecitabine and bevacizumab. Secondary endpoints were downstaging-rate and induction of complete pathological response. Material and methods: Patients with cT3 rectal cancer were eligible. Capecitabine (825 mg/sqm twice daily on radiotherapy-days weeks 1-4) and bevacizumab (5 mg/kg on days 1, 15 and 29) were administered concurrently to pelvic radiotherapy (1.8 Gy daily up to 45 Gy in 5 weeks). Surgery followed 6-8 weeks later. A two-stage trial was designed with early termination at eight patients if more than three patients had experienced a common toxicity criteria >= grade 3 according to the NCI CTC guidelines. Results: In the first stage eight patients were enrolled. Median age was 70 years (range 55-76) and ECOG PS 0/1 (%) was 87.5/12.5. Major side effects were mostly intestinal bleeding (grade 3, 25%), diarrhea (grade 3, 25%), perianal and abdominal pain (grades 3 and 4, 25%) followed by anemia (grade 3, 12.5%). Tumor downstaging was observed in 37.5% of patients with complete pathological response in two patients (25%). Conclusions: After interim analysis of feasibility and tolerability, accrual was terminated according to protocol due to >= grade 3 toxicities in 50% of patients. Complete pathological response was seen in 25% of patients but was accompanied by considerable toxicity. Further clinical trials are needed to clarify the role of bevacizumab in this setting. (C) 2011 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 102 (2012) 10-13