Increased mean corpuscular volume as a predictor of response during bevacizumab treatment

Background: Remission during sunitinib (a multikinase inhibitor and antiangiogenic drug) treatment correlates with appearance of macrocytosis. There are some suggestions that bevacizumab, an antiangiogenic drug, may result in macrocytosis as well. There are no published data available on the influence of bevacizumab on macrocytosis. This paper attempted to answer the question: does bevacizumab induce macrocytosis being a predictor of the response? Methods: Between August 2008 and August 2011, 53 patients (29 male and 24 female) were treated with bevacizumab in the combination with chemotherapy at the Oncological Department, University Hospital in Krakow, Poland. Efficacy of bevacizumab was assessed on the basis of the computer tomography scans performed every 3 months within the period of 12 months. Concurrently, mean corpuscular volume (MCV) was evaluated and correlated to the response of the treatment. Results: The percentage increase of MCV compared to baseline at 3, 6, 9 and 12 months was 3.7%, 9.2%, 8.7% and 11.8% respectively. The mean value of baseline MCV was 85.3 fl. The mean value of MCV at 3, 6, 9 and 12 months was 90.5 fl, 93 fl, 91.8 fl and 93.1 fl respectively. Macrocytosis did not occur in our study but an increase of MCV was observed within bevacizumab therapy. It was closely related to the response of the treatment. It seems that an increase of MCV can be a predictive agent of bevacizumab response. Conclusion: Bevacizumab does not induce macrocytosis. Increased MCV after treatment with bevacizumab is related to the treatment response. MCV can be a predictor of the response during bevacizumab treatment. A small number of the observed patients requires further investigations.