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Bevacizumab adds little to adjuvant chemo for colon cancer

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – Adding the anti-VEGF monoclonal antibody bevacizumab to state-of-the-art adjuvant chemotherapy for stage II or III colon cancer does not improve disease-free survival, according to a report in the Journal of Clinical Oncology online October 1.

Therefore, the authors conclude, “bevacizumab cannot be recommended for use in the adjuvant treatment of patients with colon cancer.”

Dr. Carmen J. Allegra of the University of Florida in Gainesville and colleagues note that currently, patients with stage III colon cancer are offered 6 months of adjuvant chemotherapy with regimens containing fluorouracil and oxaliplatin. Bevacizumab improves outcomes when added to chemo in patients with advanced colorectal cancer, but whether there’s a similar effect in the adjuvant setting was unknown.

To test this, the researchers randomized 2710 patients with stages II or III colon adenocarcinoma to receive 6 months of treatment with leucovorin, fluorouracil and oxaliplatin (mFOLFOX6 regimen) with or without bevacizumab for a year.

Ultimately, 1334 patients in the experimental arm and 1338 in the control arm were available for evaluation. Disease-free survival at 3 years in the two groups was 77.4% and 75.5%, respectively (p=0.15).

The effect did not vary by stage of disease. In patients with stage II disease, 3-year disease-free survival rates were 87.4% with bevacizumab and 84.7% in controls; in patients with stage III disease, these rates were 74.2% and 72.4%, respectively.

The team did see an early effect of bevacizumab on disease-free-survival, up to a 15-month landmark. “The hazard ratio before the landmark strongly favored bevacizumab (HR, 0.61; p<0.001), whereas this benefit was entirely lost subsequently (HR, 1.22; p=0.076),” according to the report. Overall, Dr. Allegra and colleagues conclude that “bevacizumab should not be used for the management of patients with stages II and III colon cancer in the adjuvant setting.” J Clin Oncol 2010.