本文报道1例家族性腺瘤性息肉病（FAP）合并直肠癌患者，通过根治性直肠前切除、根治性结肠切除、结肠横向延长术达到肿瘤根治性切除并避免永久性结肠造口，改善术后排便功能的病例。患者在第一次手术中行预防性回肠双腔造口术，现已完成造口还纳术，术后随访一般情况良好，排便功能良好，恢复正常生活。

This case report presents a patient with familial adenomatous polyposis (FAP) and low rectal cancer who underwent radical anterior resection of the rectum, total colectomy, and transverse colonic lengthening. This approach achieved complete tumor resection while avoiding a permanent colostomy and improving postoperative bowel function. The patient initially received a prophylactic loop ileostomy during the first-stage surgery, which has since been successfully reversed. During follow-up, the patient has maintained good general health, preserved bowel function, and has resumed normal daily activities.