[Evaluation of skin toxicity caused by cetuximab related to its clinical response]

Cetuximab is a recombinant, human/mouse chimeric monoclonal antibody that binds specifically to the extracellular domain of the human epidermal growth factor receptor(EGFR). This targeting agent was permitted for use with unresectable colorectal cancer patients whose tumor tissue express positive EGFR immunohistochemical staining in Japan from September 2008. Cetuximab was certified its beneficial response to KRAS wild-type patients while EGFR expression was not a proof of response. That, however, is not the only predictive factor, but skin toxicity as an adverse event is considered to be a good predictive factor. We retrospectively evaluated skin toxicity to determine whether or not its appearance would be the predictive factor of cetuximab response to 66 colorectal cancer patients in our institution. The result should that 93. 8% of patients who experienced severe skin toxity(grade 2-3)responded well(SD, PR and CR)to cetuximab.