[Two Cases of Locally Advanced Colorectal Cancer Involving Pathological Complete Response after Chemotherapy]

We report 2 cases of locally advanced colorectal cancer in which complete response(CR)was achieved after chemotherapy. Case 1 involved a 71-year-old male diagnosed with rectal cancer invading the bladder. Chemotherapy with SOX plus bevacizumab and IRIS plus bevacizumab was administered for rectal cancer. Post-chemotherapy, the disease showed clinical CR(cCR)according to the Response Evaluation Criteria in Solid Tumors(RECIST). A laparoscopic abdominoperineal resection was then performed, with pathological findings showing no viable cancer cells. Eleven months postoperatively, the patient remains alive without disease recurrence. Case 2 involved a 54-year-old female diagnosed with a peritoneal abscess resulting from perforated sigmoid colon cancer. She received chemotherapy with SOX plus bevacizumab. Post-chemotherapy, the disease showed cCR according to the RECIST. A sigmoidectomy was performed, with pathological findings showing no viable cancer cells. Ten months postoperatively, the patient remains alive without disease recurrence. We believe that neoadjuvant chemotherapy is a feasible treatment option for locally advanced colorectal cancer.