[A case of postoperative colon cancer with peritoneal dissemination in which a long-term response was achieved using...

A 66-year-old man underwent a sigmoidectomy for advanced sigmoid colon cancer. The pathological examination revealed that the tumor was T3, N0, M0, and KRAS wild type. Fifteen months after surgery, the patient was hospitalized with stenosis of the anastomosis due to recurrent disease that had disseminated to the peritoneum, and which was unresectable. After transverse colostomy, the patient received 8 courses of mFOLFOX6+panitumumab (Pmab), and 39 courses of infusional 5-fluorouracil (5-FU) + Leucovorin (LV)+ Pmab. A partial remission (PR) was maintained for 27 months. The utility of maintenance therapy with an anti-epidermal growth factor receptor (EGFR) antibody-based regime has not previously been demonstrated. In this case, a long PR was achieved using infusional 5-FU+LV+Pmab, suggesting that this is a useful maintenance therapy following mFOLFOX6 + Pmab. However, the side effects resulting from Pmab treatment reduced the patient's quality of life (QOL). We suggest that Pmab maintenance therapy can be established by controlling the side effects of the anti-EGFR antibody.