Combining Bevacizumab with chemotherapy for advanced colorectal cancer: efficacy evaluation

The present study evaluated whether combining Bevacizumab (Avastin) with chemotherapy for patients with stage IV (metastatic) colorectal cancer (CRC) has any benefits in the terms of survival and quality of life. Main findings: Bevacizumab may be beneficial only as part of certain chemotherapy regimens.

Metastatic CRC is cancer of the large intestine, rectum or appendix that has spread to other parts of the body. At this stage local treatment (surgery, radiation) is no longer effective on its own. The standard treatment for this stage of CRC is chemotherapy. Sometimes a biological treatment such as Bevacizumab is added, but its benefit is controversial. Bevacizumab is a new FDA approved drug for the treatment of some types of metastatic cancer, including CRC. Cancer cells need a blood supply in order to grow. Tumors form new blood vessels to feed themselves. Bevacizumab inhibits the growth of new blood vessels of the cancer, thereby slowing its progression.

The present analysis included 6 clinical trials with a total of 3060 patients with stage IV CRC. Participants received either chemotherapy alone, or chemotherapy plus Bevacizumab as first-line treatment for their cancer. The addition of Bevacizumab significantly extended survival (by 16% in general and by 28% without progression of the cancer), but this benefit was limited to a certain drug regimen that includes Irinotecan. On the other hand, Bevacizumab caused some serious adverse effects such as hypertension, bleeding or blood clots. Therefore, patients were more likely to stop their treatment.

In summary, based on these results, Bevacizumab (Avastin) may be recommended as adjunct to chemotherapy ONLY if the regimen includes the drug Irinotecan. Otherwise, its benefit should be weighted individually.

FDA information: Avastin (bevacizumab)