This review examined the combination of several chemotherapy agents with bevacizumab (Avastin) in the treatment of patients with advanced colorectal cancer.

Advanced cases of colorectal cancer (CRC) are generally treated with chemotherapy in addition to surgery. A combination of three drugs, 5-fluorouracil, leucovorin and irinotecan, are used most often. The treatment regimen known as FOLFIRI includes a slow infusion of these three drugs at different times over a period of 48 hours. In contrast, the IFL treatment regimen includes receiving all three drugs at once, as a bolus.

Bevacizumab inhibits the tumor’s ability to produce new blood vessels, thereby preventing cancer growth. Bevacizumab is often effectively added to IFL chemotherapy (a regimen known as IFL-B). However, few trails have assessed the addition of bevacizumab to FOLFIRI (a regimen known as FOLFIRI-B). Since the slow infusion of toxic drugs in the FOLFIRI regimen is known to cause less adverse effects compared to IFL, current clinical trials are investigating how FOLFIRI-B treatments compare to IFL-B or FOLFIRI alone.

This review analyzed data from 29 studies, including a total of 3502 patients. Results from each of these studies were combined, and the response rate to treatment, progression free survival (PFS; the time between treatment and until the disease worsens, or the cancer progresses) and the rate of serious complications were analyzed.

The overall response rate (assessed by evidence of tumor shrinkage) to FOLFIRI-B was 51.4%. Patients receiving FOLFIRI-B experienced an average of 10.6 months of PFS, and overall survival averaged 23.7 months. 18% of patients with liver metastasis (spread of the cancer to the liver) were able to undergo surgery to remove these tumors.
Grade 3 or 4 toxicities (severe to life-threatening complications due to treatment) included hypertension (high blood pressure) in 6.2% of patients, bleeding in 2.28% of patients, and blood clots in 8.9% of patients.

This review concluded that FOLFIRI-B is an effective chemotherapy regimen. FOLFIRI-B results in extended progression free survival and high response rates, with low rates of severe toxic events.

This analysis combined data from several different studies, all researching different chemotherapy regimens including FOLFIRI-B. However, despite these encouraging results, no direct comparison was performed in a controlled manner between FOLFIRI-B and FOLFIRI or IFL-B treatments. 

Consult with your physician regarding the risks and benefits of the different chemotherapy regimens available in the treatment of colorectal cancer.