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

Background: Multimodality treatment of rectal cancer, with the combination of radiation therapy, chemotherapy, and surgery has become the preferred approach to locally advanced rectal cancer.The considerably high local recurrence rates observed after radical surgery alone has led to the use and recommendation for additional therapy either before or after surgery for T3/T4 or N1 tumors. In this setting, to avoid overtreatment of patients with early-stage disease, preoperative treatment with radiation therapy with or without concomitant chemotherapy requires optimal radiological staging because there is no pathologic confirmation of exact TNM parameters. However, there is a theoretic benefit of exposing unscarred tissue with optimal oxygen delivery to both radiation and chemotherapy as opposed to postoperative treatment. The results from randomized controlled trials suggest that the neoadjuvant approach seems to be superior for local disease control, even in the setting of appropriate surgical technique (total mesorectal excision). The use of neoadjuvant chemoradiation therapy (CRT) has resulted in additional benefits such as reduced toxicity rates, significant tumor downsizing and downstaging, better chance of sphincter preservation, and improved functional results (compared with postoperative CRT). In a multicenter study of patients undergoing neoadjuvant CRT for clinically stage II disease (staged by either endorectal ultrasound or magnetic resonance imaging), more than 20% of the patients staged as N0 were found to harbor lymph node metastases in their tumors on pathologic examination. Considering that these patients underwent neoadjuvant CRT, even greater rates of nodal disease underestimation might be expected. Radical surgery with total mesorectal excision remains the mainstay of treatment of distal rectal cancer and is considered by many to be necessary regardless of tumor response to neoadjuvant CRT. However, it has been associated with high rates of immediate morbidity and mortality. With very low tumors, abdominoperineal resection sometimes is necessary with the result of permenant colostomy and disturbance of the quality of life. Up till now, many authors believe that the decision of surgery should be set before any change in the tumor by neoadjuvant chemoradiation, however haber-gama who concluded that with complete pathologic response and restrict criteria, it is safe just to follow up the patient without surgery. Changing decision to sphincter preserving technique in patients who have good response to neoadjuvant chemoradiation with downsizing and downstaging is still contraversail. Aim of the work: To study the safety of changing decision from abdominoperineal resection to sphincter preserving technique in low rectal tumors after downsizing be neoadjuvant chemoradiation. Aspects of safety will include periperative morbidity, mortality, continence, recurrences and results of salvage surgery after recurrence. Study design: Patients with stage II and III low rectal cancer less than 5 cm from anal verge usually need abdominoperineal resection. Preoperative neoadjuvant chemoradiation 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. If no sufficient safety margin, intersphincteric resection 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.