The relationship between treatment response, proteinuria and other clinical factors in patients with metastatic colorectal cancer receiving bevacizumab-based chemotherapy

Efficacy of bevacizumab -which is widely used at metastatic colorectal cancer (mCRC)- on clinical survival has been proved. But parameters predicting this clinical efficacy are unknown at present. With this study, we aimed to investigate the predictors of treatment benefit with bevacizumab based chemotherapy in patient with mCRC. Thirty-six successive patients with mCRC receiving bevacizumab based chemotherapy were enrolled to the study. Hypertension, 24-hour proteinuria and other routine parameters were recorded before and during the treatment with certain intervals. After a 1-year followup, relationship of progresyon-free survival (PFS) and response with various parameters and especially proteinuria, was evaluated. Of 36 patients included, 20 (55.6%) were male and 16 (44.4%) were female, where mean age was 57. Overall median PFS was calculated as 275 days (9.8 months). At patients with basal proteinuria higher than 114 gr/day had a lower median PFS such as 184 days (6.5 months) (p=0.046), where median PFS of patients with basal proteinuria equal to or lower than 114 gr/day was not reached. Therefore, the level of renal proteinuria is a negative prognostic factor for these patients. Similarly, PFS was observed to be lower at patients with high LDH levels (p=0.0024, Exp(B)=23). Bevacizumab response was observed to be better at patients with favorable performance status (p=0.05), who have a single liver metastasis (p=0.034) and who tend to be hypertensive during the treatment (p=0.034). In our study, we demonstrated that basal proteinuria and LDH levels may be prognostic at patients with mCRC receiving bevacizumab-based treatment. In literature, there has been no study up to now regarding basal proteinuria as a prognostic factor for patients receiving bevacizumab-based treatment. Our observation about the prognostic importance of basal proteinuria for patients with metastatic colorectal cancer receiving bevacizumab is an important step for more focused use of bevacizumab. We believe that it is important to investigate whether basal proteinuria has a predictive role in this group of patient with further studies, and this has practical and clinical implications. Key words: Bevacizumab, metastatic colorectal cancer, prognostic and predictive factors, proteinuria.