Clinical Factors Affecting Bevacizumab Efficacy With and Without Conventional Chemotherapy in Metastatic Colon Cancer

Bevacizumab (BZ) combined with first line chemotherapy (CC) has shown good clinical outcomes in metastatic colorectal cancer (mCRC). Overall survival (OS) and/or progression free survival in mCRC patients receiving BZ with or without 5FU-based CC is thought to be affected by clinical and morphological factor(s).

We reviewed retrospective medical records of all consecutive mCRC patients treated with BZ with or without CC at tertiary care center between 2003 and 2009 out of which149 patients (m = 77, f = 72) were eligible.

Our study population had a mean age at diagnosis of 63.5 years (SD = 11) with median follow-up period of 19.4 months. On initial radiological evaluation following BZ therapy, 56 patients (m = 31, f = 25) had complete or partial response categorized as "early responders." Remaining patients (m = 46, f = 47) who were either stable or showed progressive disease were categorized as "non-responders." Fifty percent among early responders and 60% among non-responders [relative risk (RR) 0.67 (95% confidence interval (CI), 0.43-1.06)] demonstrated disease progression on follow up. There was a slightly better OS among early responders compared to non-responders (median 21.5 months days versus 16.8 months, P = 0.07). Cox regression analysis suggested male sex (RR 0.65, 95% CI, 0.43-0.98), hematochezia (RR 0.63, 95% CI, 0.4-0.98), resectable primary tumor (RR 0.42, 95% CI, 0.24-0.72) and resectable metastatic mass (RR 0.32, 95% CI, 0.14-0.74) were found to be associated with longer OS. Abdominal pain (RR 1.76, 95% CI, 1.1-2.8), accompanying diabetes (RR 1.76, 95% CI, 1.09-2.85), and unexplained weight loss (RR 2.73, 95% CI, 1.73-4.29) were associated with poor OS.

Better OS among mCRC patients with resectable primary and metastatic tumors was seen. This is the first study to demonstrate slightly better outcome in males and negative influence of diabetes on outcome in mCRC treated with BZ.