[A Case of Rectal Cancer Treated with Robot-Assisted Abdominoperineal Resection and Lateral Lymphadenectomy after Neoadjuvant Chemoradiotherapy].

A 78-year-old man was referred to our institution with bloody stools. Colonoscopy revealed advanced rectal cancer with stenosis at the lower rectum(anal verge 4-12 cm). Biopsy findings revealed highly differentiated adenocarcinoma. Magnetic resonance imaging(MRI)/computed tomography(CT)/positron emission tomography(PET)showed the tumor on the rectal wall, mesenteric lymph nodes, and an enlarged left lateral lymph nod(e No. 283), but no metastasis was detected. The patient was diagnosed with rectal cancer(cT4aN3M0, cStgae Ⅲc)and received neoadjuvant chemoradiotherapy(CRT) (50.4 Gy irradiation of the primary tumor and small pelvis, including the lateral lymph nodes, and oral capecitabine). After CRT, the diagnosis was revised to ycT2N3M0, ycStage Ⅲb. He subsequently underwent robot-assisted abdominoperineal resection and D3+ltLD2 dissection. Lymph node metastasis was detected in No. 283-lt and No. 241, and the pathological diagnosis was ypT2N3M0, ypStage Ⅲb. Histological evaluation of response to treatment was Grade 2. He showed a favorable postoperative course and was discharged on postoperative day 18. He received 8 courses of adjuvant chemotherapy with CAPOX from postoperative day 32 and is alive with recurrence-free 9 months after surgery. This case suggests that CRT is a viable option for treating locally advanced rectal cancer.