Evaluation of Hypertension as a Predictor of Efficacy Bevacizumab in Metastatic Breast Cancer and Colorectal Cancer

Hypertension (HT) is the most common side effect seen in trials of bevacizumab in combination with chemotherapy. Based on the hypothesis that the development of hypertension during treatment would be an indicative of the successful blockade of the Vascular Endothelial Growth Factor (VEGF) pathway, different studies have explored retrospectively the relationship between hypertension and the results of treatment with bevacizumab. This study aims to demonstrate the association between hypertension (diagnosed optimally) with efficacy to treatment with bevacizumab prospectively and secondly verify if blood pressure measures taken at home are a reflection of a diagnosis of hypertension. Also have been explored different molecular markers involved in the pathway of VEGF which might be used as predictors of response. Therefore, this study includes the collection of blood samples (serum or plasma) and tumor tissue of patients included in this study, with the aim of exploring biomarkers that correlate with treatment efficacy and toxicity. The diagnosis of hypertension (HT) will be performed using a Holter recording, and standard blood pressure footage will be collected during the first three cycles of treatment given the Common Toxicity Criteria of the National Cancer Institute-NCI CTCAE version 4.0 and the guidelines of the European Society of Cardiology and Hypertension, 2007. Will be collected a sample of primary tumor and blood for patients who previously have consented it. Samples will be sent to a central laboratory for analysis of biomarkers. An interim analysis will be conducted to assess the true incidence of hypertension. Based on this analysis, will be evaluated the need to recalculate the sample size. At the end of the study, will be performed an analysis of correlation of data measured by standard BP (Blood Pressure) and Holter recording footage with the PFS. Moreover will be determined in serum, plasma and tumor tissue and certain biomarkers to correlate with efficacy to treatment with bevacizumab.