Oral mucositis caused by targeted therapy for colorectal cancer: which drug is safer?

This study investigated the frequency and severity of oral mucositis (OM) in patients with colorectal cancer treated with chemotherapy and panitumumab (Vectibix) or cetuximab (Erbitux). Researchers suggested that panitumumab ?is associated with increased levels of OM in these patients.

Colorectal cancer is the fourth most common cancer in the US. Chemotherapy and radiation therapy are the standard treatments for these patients. In some cases, targeted therapy is added to the treatment to increase cancer response. Targeted therapy such as anti-EGFR antibodies (panitumumab and cetuximab) attack specific proteins in cancer cells stopping them from growing.

Oral mucositis (OM) is a common complication of cancer treatment. OM consists of a painful mouth inflammation with the presence of ulcers. Prior studies showed no differences in OM in patients being treated with cetuximab or panitumumab alone. However, it is not known if there are any differences in OM in patients being treated with targeted therapy combined with chemotherapy.

This study included information about 75 patients with colorectal cancer. They were treated with chemotherapy (FOLFOX, FOLFIRI or 5-FU/leucovorin) combined with either panitumumab (32; group 1) or cetuximab (43; group 2). Side effects such as OM were evaluated.

The presence of mild to severe OM was increased in patients from group 1 (31.3%) when compared with group 2 (9.3%). Severe OM was also more common in group 1 (18.8%) than in group 2 (0%).

This study also assessed the presence of other negative side effects. Skin reactions were less common in patients from group 1 (68.8%) when compared to group 2 (74.4%). Low levels of magnesium in the blood were higher in group 1 (9.3%) when compared to group 2 (7%). An increased rate of low immune cells was seen in the blood of patients from group 2 (37.2%) when compared to group 1 (28.1%).    

This study showed that patients with colorectal cancer treated with panitumumab combined with chemotherapy had increased rates of OM.

This study was based on the medical records of patients, which might contain missing information. The number of patients included was also very small. Further studies are needed regarding the safety of this treatment combination.

Talk to your doctor if you have any concerns about OM.