Evaluation of hypertension and proteinuria as markers of efficacy in antiangiogenic therapy for metastatic colorectal cancer.

Background: The vascular endothelial growth factor pathway is strongly implicated in cancer-related angiogenesis. Antiangiogenic agents such as bevacizumab commonly cause hypertension (HTN) and proteinuria (PTN), which may be biomarkers of response and clinical outcome.

Study: We conducted a retrospective analysis of patients with histologically proven metastatic colorectal cancer (mCRC) treated with either bevacizumab or a tyrosine kinase inhibitor in combination with chemotherapy at The Christie Hospital from January 2006 to September 2009.

Results: Of 90 patients evaluated, 50 were eligible. Seventeen (34%), 4 (8%), and 3 (6%) patients developed Common Toxicity Criteria (v 3.0) grades 1, 2, and 3 HTN, respectively. Response rates were 42% for patients with grades 0 to 1 HTN compared with 86% for patients with ≥grade 2 HTN (P=0.043). Median overall survival was 21.6 months for patients with grades 0 to 1 HTN and 25.2 months for patients with ≥grade 2 HTN (P=0.270). Twelve patients (24%) developed grade 1 PTN and 4 patients (8%) developed ≥grade 2 PTN. Median overall survival was 23.9 months for patients with grades 0 to 1 PTN and 4.2 months for those with ≥grade 2 PTN (P=0.028).

Conclusions: To our knowledge, this is the first study to demonstrate the utility of PTN as a surrogate marker of outcome in antiangiogenic therapy for metastatic colorectal cancer. Although HTN is predictive of a significantly higher response rate, the development of PTN during treatment with bevacizumab or tyrosine kinase inhibitor portends poorer survival and should be evaluated prospectively.