Retrospective analysis of pathologic response in colorectal cancer liver-only metastases following treatment with bevacizumab.

674 Background: Recent reports have shown that pathological response predicts for better outcome (overall survival) following preoperative chemotherapy and surgical resection of colorectal cancer (CRC) liver-only metastases. The aim of this retrospective analysis was to evaluate the effect of adding bevacizumab to standard chemotherapy on pathological response in patients with CRC liver only metastases. Methods: Patients with stage IV CRC with liver metastases who received neoadjuvant chemotherapy (oxaliplatin-or irinotecan-based) at two Spanish centres were analysed retrospectively. Pathological response was evaluated as follows: complete pathological response (cPR), PR1 (25% of residual tumour), PR2 (25–50% of residual tumour), PR3 (>50% of residual tumour). cPR or PR1 was considered to be a good response, and PR2 or PR3 a poor response. Results: A total of 81 patients were evaluated. Of these, 43 received chemotherapy alone and 38 received chemotherapy plus bevacizumab. Baseline characteristics were as...