Proctectomy with sphincter preservation in very low rectal cancer that traditionally need abdominoperineal resection with permanent colostomy

Interventions: Patients with stage II and III low rectal cancer less than 5 cm from anal verge usually need abdominoperineal resection. Preoperative neoadjuvant chemoradiation(54 grays of radiation divided over 5 weeks with chemotherapy by intravenous 5-fu and leucovorin 1 day a week for 5 weeks; 5-FU 425 mg/m2 plus LV 45 mg ) helps in tumor downstaging and downsizing that might help to resect the tumor with safety margin without removing the anal sphincters. Patients with T3, T4 low rectal tumors 5 cm or less from anal verge receive neoadjuvant preoperative chemoradiation. Patient assessment is done 8 weeks after the end of chemoradiation by digital rectal examination and endorectal ultrasound. If there is tumor downsizing that leaves safety margin above the anal sphincters, , then very low anterior resection with coloanal anastomosis is performed (120-180 minutes) . If no sufficient safety margin, intersphincteric resection (120-180 minutes) with coloanal anastomosis is done if the external anal sphincter is not involved (yT2), if the external sphincter was involved so abdominoperineal resection is done and excluded from study.
Primary outcome(s): Perioperative morbidity assesed by clinical examination of the abdomen to diagnose wound problems, chest x ray and Ultrasound abdomen[1-30 days postoperative];Perioperative mortailty[1-30 days postoperative];Tumor recurrence assessed by clinical examination and abdominal CT scan[every 6 months postoperative for 2 years]
Study Design: Purpose: Treatment; Allocation: Non-randomised trial; Masking: Open (masking not used);Assignment: Single group;Type of endpoint: Safety/efficacy