The relationship between treatment response and clinical parameters in patients with metastatic colorectal cancer receiving bevacizumab-based chemotherapy

Bevacizumab is monoclonal antibody which has a proven efficacy in metastatic colorectal cancer. Present study is focused on finding readily available parameters that have the ability to demonstrate the success of chemoimmunotherapies which contain bevacizumab.In the study 35 metastatic colorectal cancer patient which used bevacizumab plus various chemoimmunotherapies are assessed retrospectively. CEA, LDH, CRP, complete blood count parameters were recorded in the beginning and every three months after wards for a period of one year.Median age of the patients were 58.3 (minimum 29, maximum 79), 26 of the patients were male (72.4%) and 9 were female (25.8). Majority (23 patients) of the tumors were localized in rectosigmoid. Progression free survival was 345 days (11.5 months) and overall survival was 1020 days (34 months). Overall survival was higher in patients whose Karnofsky performance score were above 85% (p=0.009).Overall survival was found to be higher in the patients whose hemoglobin levels at 6 month were higher than the mean level (p=0.049). However, the progression free survival of them was not found to be improved significantly. Progression free survival was found to be higher in the patients whose blood eosinofil counts at 0, 6, and 9 months were above the mean levels of corresponding values (p values are 0.016, 0.049 and 0.019 respectively). Another the significant positive relation was found between the platelet level of patients at 9 months and progression free survival (p=0.019).To our knowledge, this is the first report in the literature that demonstrate a positive correlation between progression free survival and eosinophil level for the bevacizumab-based chemoimmunotherapy administered metastatic colorectal carcinoma patients. Another result, positive correlation between overall survival and Karnofsky performance score has been described in the literature previously. Further studies exploring the relation between survival and leukocyte subsets are urgently needed in monoclonal antibody based treatments