P1-288Complete pathological response after preoperative chemotherapy for locally advanced rectal cancer: a case report

Abstract Background For locally advanced rectal cancer in Japan, radical surgery including lateral lymph node dissection followed by postoperative chemotherapy is the standard treatment. However, with regard to preoperative chemotherapy for locally advanced rectal cancer, its significance and efficacy remains controversial. The present study reported the apparent effectiveness with complete pathological response of conversion surgery including mFOLFOX6 plus bevacizumab and radical surgery. Additionally, we review the relevant literature and discuss the clinical management including preoperative chemotherapy for locally advanced rectal cancer. Case presentation A 59-year-old male presented with severe constipation, bloody stool and loss of 10 % of body weight over 3 month. Preoperative examination revealed locally advanced rectum cancer with extensive invasion of bladder wall and regional enlarged lymph nodes. Thus, this lesion was assigned a preoperative classification of T4bN2bM0 stage IIIC according to the 8th Union for International Cancer Control (UICC) guidelines. Therefore, the patient initially underwent external loop colostomy with transverse colon. Next the patient received the chemotherapy including mFOLFOX6 plus bevacizumab. After 12 course of chemotherapy, the tumor size was markedly decreased and all lymph nodes metastasis had disappeared. Therefore, the patient underwent conventional resection of rectum with D3 lymph node dissection and closure of colostomy. The histopathological analysis of the specimen revealed that all lesions were fibrotic, devoid of any viable cancer cells. Thus, this lesion was assigned a final classification of ypT0N0M0 stage 0 according to the 8th UICC guidelines. Conclusions We present a rare case with complete pathological response of conversion surgery with combination treatment including mFOLFOX6 plus bevacizumab and radical surgery.