Over 70? Bevacizumab is safe and effective for treating metastatic colorectal cancer

This study evaluated the safety and efficacy of bevacizumab (Avastin) in patients with metastatic colorectal cancer aged 70 and above versus younger patients.

Bevacizumab is a new biologic therapy (a medicine extracted from biological sources e.g. produced by cell lines) for cancer treatment. It works by blocking the creation of blood vessels the tumor needs for growth. Previous trials have shown that it improves progression-free survival (time following treatment before the disease progresses) and overall survival when combined with standard chemotherapy protocols in patients with metastatic colorectal cancer (colorectal cancer that has spread to other organs).

The incidence of metastatic colorectal cancer is higher in older patients (65 years or more, 204 cases per 100,000) compared to younger patients (less than 65 years, 17 cases per 100,000). Despite this, the majority of previous studies have not assessed the safety and efficacy of bevacizumab in elderly patients. 

This study analyzed medical records of 308 patients with metastatic colorectal cancer. 92 patients were 70 years or older and 216 patients were younger than 70. All patients received bevacizumab plus another routine first-line (or first and second line) chemotherapy regimens. Adverse events, overall survival and progression free survival were evaluated to indicate safety and efficacy of bevacizumab.

At the beginning of treatment older patients had significantly more ischemic heart disease (reduced blood supply to the heart, 20.7% compared to 3.7%) and hypertension (high blood pressure, 65.2% compared to 26.4%). Older patients were also less likely to be treated with FOLFOX (5-fluorouracil [Efudex], leucovorin, oxaliplatin (Eloxatin]) and more often with 5-fluorouracil plus leucovorin.

Overall survival and progression-free survival were similar in younger and older patients. Average overall survival was 32 months for younger patients and 26 months for older patients. Average progression-free survival was 15 months for younger patients and 13 months for older patients.

Rates of adverse events were generally similar for older and younger patients. However, 14.1% of older patients experienced proteinuria (excess protein in patients’ urine) compared to only 5.6% of younger patients. Older patients also tended to be more likely to develop hypertension during the first 3 months of treatment, 16.3% compared to 8.8% of younger patients. Rates of wound healing complications were lower for older patients, 5.4% compared to 13.4% of younger patients. Overall 1.9% of patients died due to bevacizumab-related adverse effects; all were younger than 70 years.

The authors concluded that in this group of patients, bevacizumab was safe and effective in older as well as younger patients.