[A Case of Sigmoid Colon Cancer with Distant Metastasis Successfully Treated with First-Line Cetuximab Monotherapy]

The patient was a 59-year-old woman with progressive sigmoid colon cancer with multiple metastasis(T3N2M1b[P2, H3, PUL2]Stage IV ). As the RAS gene in the patient was wild-type, we administered cetuximab monotherapy every week. One month after chemotherapy initiation, the tumor marker levels declined and the tumor size reduced. Patient's general condition was improved and mFOLFOX6 therapy was then continued in addition to cetuximab. As a side effect, acne-like rash is only grade 1 to 2, and there are no other serious side effects. Cetuximab monotherapy may contribute to the treatment of poor PS patients.