First line 5-FU-based chemotherapy with/without bevacizumab for metastatic colorectal cancer: one center experience results

Abstract

Purpose: Colorectal cancer is the second leading cause of cancer mortality in the United States. According to the National Institute of Statistics in Bulgaria for 2012 there have been 2370 newly diagnosed colon cancer and 1664 rectal cancer cases and the total number of registered patients is 29995. Adding Bevacizumab to chemotherapy in patients with metastatic colorectal cancer improves progression-free survival but yet no predictive markers for patient selection have been described and proved in the clinical practice. In our study we examined two plasma biomarkers that may correlate with response to first line Bevacizumab containing chemotherapy in patients with metastatic colorectal cancer.
Patients and Methods: 54 patients with metastatic colorectal cancer were assigned to first line 5-Fubased chemotherapy with/without Bevacizumab. The primary end point was progression-free survival, with additional determination of response and toxicity. Blood samples were collected at baseline from all 54 patients prior to initiation of chemotherapy and Bevacizumab. Plasma samples were stored at -80º C until analysis at the Immunology Laboratory at the University Hospital `St. Marina` (Varna, Bulgaria) by a multiple-step sandwich immunoassay Human ELISA VEGF121 and VEGF165 kits.
Results: The median progression-free survival for the group treated with CT/Bev was 8.8 months, compared with 5.4 months for the group treated with chemotherapy alone (95% CI, log-rank test P =0.003). The corresponding overall response rates were 19.3% and 10.2% respectively (P < 0.05 for CT/Bev vs CT).
Conclusion: The addition of Bevacizumab to 5-Fu based chemotherapy improves progression-free survival duration for patients with metastatic colorectal cancer. We could not find any association between pretreatment plasma levels of VEGF 121 and 165 and worse PFS.