Vimal, a 70 years old male presents with a h/o lower GI bleed for last 6 months. Sigmoidoscopic examination shows a mass, of 4 cms about 3.5 cms above the anal verge. The treatment of choice is ?
Ans. is 'c' ie. Abdominoperineal resection Treatment of rectal cancer Surgical and oncologic management varies greatly depending on the stage and location of the tumor within the rectum. Superficially invasive, small cancers may be managed effectively with local excision. However, most patients have more deeply invasive tumors that require major surgery, such as Low anterior resection (LAR) or APR. a) Low anterior resection: This is sphincter saving procedure. In this procedure the sigmoid colon and proximal rectum are removed The descending colon is anastomosed to the distal rectum. Previously this sphincter saving LAR procedure was possible for lesions confined in upper 2/3'd of rectum. Lesions in lower third were treated with APR with permanent colostomy. With the introduction of stapling gun, the sphincter saving LAR operation can now be done even in lesions of lower 1/3 rectum, provided a margin of 2 cm or more of normal bowel can be resected below the lesion but above the dentate line. (some books write that even 1cm margin can be adequate, but provided the carcinoma is well differentiated) Devito Oncology writes- "Tumors within 1 to 2 cm of the dentate line, that is those that can be removed with at least a 1-cm distal margin, can be resected and intestinal continuity restored with a coloanal azzastomosis." b) Abdominoperineal resection (also k/a Miles procedure) : There is complete excision of the distal sigmoid colon, rectum and anus, by concomitant dissection through the abdomen and perineum with creation of a permanent colostomy. APR is performed when adequate distal margins for low anterior resection cannot be obtained i.e. for carcinomas in lower rectum. c) Local excision: In carefully selected patients with small, well differentiated, superficial, mobile polypoid lesions, a full thickness excision can be performed through the transanal route as the definitive therapy. Local excision can be done for selected T1 and T2 lesions without evidence of nodal disease. Transanal excision can spare the patient the morbidity of a more extensive rectal resection. However, it does not stage the nodal drainage areas and therefore cannot provide as complete staging and management of the tumor as a definitive resection. Tumors considered for local excision must meet a number of criteria to minimize the risk of local regional recurrence. Devita's Oncology writes- "Generally, local excision is limited to tumors within 8 to 10 cm of the anal verge, encompass less than 40% of circumference of the bowel wall, are of well or moderately well differentiated histology, and have no pathological evidence of venous or lymphatic vessel invasion on biopsy." Various technical approaches have been described to achieve transanal local excision, including use of a special proctoscope equipped with a magnifying camera (transanal endoscopic microsurgery). Transanal endoscopic microsurgery makes use of a specially designed proctoscope, magnifying system, and instruments similar to those used in laparoscopy to allow local excision of lesions higher in the proximal rectum. d) Palliative procedures: Unresectable rectal cancers can be palliated by fulgration (electrocoagulation) or laser photocoagulation. e) Chemoradiation: Chemoradiation can be given as adjuvant or neoadjuvant therapy. Also know: Haman's procedure This is a compromise type of resection in which the rectum and/or sigmoid colon are resected and an end colostomy done. Anastomosis and perineal dissection of the distal rectum and perineum are not done. This procedure is used - if there is too much obstruction or sepsis to allow a safe anastomosis. - for elderly or severly unstable pts. who would not stand a lengthy ant resesction or an APR procedure. In this pt. the tumor lies 3.5 cms above the anal verge (the lower limit is taken into consideration). Dentate line is 2 cm from the anal verge (Ref: Devito Oncology 8/e), so this lesion is just about 1.5 cm above the dentate line. A minimum margin of 2 cm is required below the tumor for sphincter saving LAR, so this patient will have to go an APR procedure to remove the tumor.
Colostomy
Anterior resection
Abdominoperineal resection
Defunctioning anastomosis