[A Case of Long-Term Clinical Complete Response after Chemotherapy for Locally Advanced Rectal Cancer]

With the advancement ofchemotherapy against colorectal cancer, clinical complete responses(cCR)are more frequently observed. We report a case oflocally advanced rectal cancer with maintained long-term cCR after chemotherapy alone. Detailed examinations ofa man in his 60s revealed that he had poorly controlled diabetes mellitus, with elevated serum CEA and CA19-9 levels. Colonoscopy revealed rectal cancer(Rba). Besides the prostate invasion observed in the CT scan, intestinal obstruction was caused by a tumor that required surgical removal. However, the tumor was unresectable due to prostate and pelvic wall metastases; therefore, only sigmoid colostomy was performed. After 6 courses of mFOLFOX6, the tumor shrunk, and prostate invasion reduced as confirmed by the CT scan. Chemotherapy was switched to sLV/5FU2 due to the occurrence of peripheral neuropathy. No tumor was found after 20 courses of treatment, and cCR was achieved after 58 courses ofcontinuous and consecutive treatment. Throughout the treatment, radical resection was proposed to the patient; however, the surgery was not performed because of his lifestyle, ie, heavy smoking, which resulted in poor blood sugar control. The patient appears to be tumor free for 7 years after the initiation of chemotherapy.