Bevacizumab plus mFOLFOX6 improves the outcomes of patients with colorectal cancer and liver metastasis

This study investigated the effects of bevacizumab (Avastin) combined with mFOLFOX6 (fluorouracil, leucovorin, and oxaliplatin) treatment in RAS-positive advanced colorectal cancer (CRC). Researchers suggested that this treatment improved the treatment and survival outcomes of patients with CRC and liver metastasis (spread to the liver).

CRC is one of the most common cancers worldwide. A significant number of patients present with metastatic disease at diagnosis. The most common site of metastasis in these patients is the liver. In these cases, chemotherapy is only of limited effectiveness. Therefore, combined treatment with agents such as targeted therapy is often used.

Prior studies suggested that oxaliplatin-based chemotherapy (such as mFOLFOX6) plus targeted therapy downsize liver metastasis in patients with CRC. This can allow for surgical removal of liver metastasis. Bevacizumab is a type of targeted therapy that blocks the growth of blood vessels in tumors. This blocks tumor growth and spread. This agent has been showing to improve the survival of advanced CRC patients. It downsized the metastasis to an operable size. However, it does not show the same level of effectiveness when the cancer is RAS-positive.     

RAS mutation (a permanent change in the gene) increases cancer's aggressiveness and ability to spread. Prior studies on RAS-mutated CRC included a small number of participants and other limitations. The effectiveness of mFOLFOX6 plus bevacizumab in the treatment of RAS-mutated CRC with inoperable liver metastasis is still not clear.  

This study included information about 241 patients with RAS-mutated CRC and liver metastasis. These patients received either mFOLFOX6 plus bevacizumab (group 1; 121) or mFOLFOX6 alone (group 2; 120). The average follow-up period was 37 months.

22.3% of the patients in group 1 and 5.8% in group 2 had complete removal of liver tumors after treatment. Patients from group 1 also had better response rates (54.5%), when compared to group 2 (36.7%). They also had better progression-free survival (time from treatment to disease progression; 9.5 months), when compared to group 2 (5.6 months). The average overall survival was 25.7 months for group 1 and 20.5 months for group 2.

More patients in group 1 reported serious side effects (39.7%) compared to group 2 (26.7%). Group 1 had increased protein the urine (9.9%) when compared to group 2 (3.3%). High blood pressure was also more common in group 1 (8.3%) when compared to group 2 (2.5%).

This study concluded that mFOLFOX6 plus bevacizumab improved treatment response and survival rates of patients with RAS-mutated CRC and liver metastasis. 

This study was done in a single medical center. Therefore, the results may not apply to all hospitals. Also, after disease progression, there was no protocol for further treatment. Therefore, the treatment given after disease progression might have influenced overall survival.