The current study evaluated the effect of bevacizumab added to fluoropyrimidine‐plus‐oxaliplatin (5FU/OX) chemotherapy for colorectal liver metastases (CLM) on the pathologic response and nontumorous liver histology.

A total of 105 consecutive patients treated preoperatively with 5FU/OX chemotherapy with (n = 62) or without (n = 43) bevacizumab were analyzed. The response to chemotherapy was evaluated by pathologic analysis of tumor viability (percentage of viable tumor in relation to tumor surface area). The incidence and grade of hepatic sinusoidal dilation were also investigated.

Bevacizumab‐containing regimens significantly reduced the degree of tumor viability compared with 5FU/OX‐only chemotherapy (32.9% vs 45.3%; P = .02). After stratification according to the magnitude of tumor viability, a higher proportion of patients treated with bevacizumab than without had <25% residual viable tumor cells (45% vs 23%; P = .02). However, the addition of bevacizumab to 5FU/OX did not appear to increase the incidence of complete pathologic response (11.3% vs 11.6%; P = .59). The incidence and severity of sinusoidal dilation was lower in patients treated with bevacizumab than in those treated with 5FU/OX only (any grade: 27.4% vs 53.5%; moderate or severe: 8.1% vs 27.9%; both P < .01).

In patients treated with 5FU/OX chemotherapy, bevacizumab improves the pathologic response, as demonstrated by a reduction of the degree of tumor viability, and reduces the incidence and severity of hepatic injury. This retrospective study provides additional evidence supporting the use of bevacizumab in combination with 5FU/OX for CLM. Cancer 2007. © 2007 American Cancer Society.