Successful treatment of a patient using mFOLFOX6 after laparoscopic surgery for rectal cancer with peritoneal dissemination

A 58-year-old man underwent laparoscopic surgery for rectal cancer(rectal sigmoid)complicated by intestinal obstruction. He had no liver metastasis. Although many nodules suspected to have arisen from peritoneal dissemination were observed in the pelvic cavity, we performed anterior resection assuming that the primary lesion was resectable. The surgical findings were sSE, sN2, sP3, sStage IV, and histopathological findings were signet-ring cell carcinoma, pSE, pN2, pP+, pStage IV. After 8 courses of adjuvant chemotherapy with modified 5-fluorouracil/Leucovorin/oxaliplatin(mFOLFOX6), carcinoembryonic antigen( CEA)decreased to a normal level, and positron emission tomography-computed tomography(PET-CT)showed no abnormal accumulation that suggested metastasis. To evaluate the effectiveness of this procedure, laparoscopic peritoneal biopsy was performed 5 months after surgery, revealing histopathological disappearance of the peritoneal dissemination lesion. The patient has been followed up and has been receiving S-1 for 1 year after the first surgery. No evidence of recurrence has been observed.