[A Case of Pathological Complete Response with Neoadjuvant Chemotherapy for Advanced Rectal Cancer]

A 62-year-old man was admitted with complaints of bloody stool. Colonoscopy revealed a 5 cm diameter type 2 tumor in the lower rectum close to the anal canal. Tumor biopsy indicated a well-differentiated tubular adenocarcinoma. Computed tomography revealed locally advanced rectal cancer with mesorectal lymph node metastases(cT3N1P0M0, Stage Ⅲa, JSCCR 8th). The patient was treated with neoadjuvant chemotherapy(NAC)after transverse colostomy as an anus-preserving procedure. For the NAC, 12 courses of capecitabine plus oxaliplatin(CapeOX)and bevacizumab(BV)were administered. Colonoscopy after NAC revealed that the main tumor had considerably shrunk. No malignant tissues were found on biopsy. However, rectal wall thickness remained unchanged. Therefore, response evaluation for chemotherapy indicated partial response. Intersphincteric resection(ISR)with diverting loop ileostomy was performed as an anus-preserving surgical procedure. No remnant tumor in the rectum or lymph node metastases were found upon the pathological examination of resected specimens. Ileostomy closure was performed at 6 months post-ISR. At 12 months post-ISR, the patient was well and showed no signs of recurrence. This case demonstrated that NAC with CapeOX and BV can be a promising option for treating locally advanced lower rectal cancer and preserving the anus.