Surgical resection is indicated for colorectal adenocarcinoma, regardless of stage. Resection of the primary lesion prevents obstruction or perforation.
Extremely advanced rectal lesions, which are not resectable, may be candidates for palliative radiation and a diverting colostomy.
The extent of resection is determined by the relationship of the lesion to the lymphatic drainage and blood supply of the colon.
Cecum or right colon. Right hemicolectomy.
Hepatic flexure. Extended right hemicolectomy.
Mid-transverse colon: Transverse colectomy or extended left or right hemicolectomy.
Splenic flexure or left colon. Left hemicolectomy.
Sigmoid colon. Sigmoid colectomy.
Upper or middle rectum. Low anterior rectosigmoid resection with primary anastomosis.
Lower rectum. Abdominoperineal resection with permanent end colostomy or local excision in selected cases.
Preoperative bowel preparation
Mechanical cleansing of the lumen, followed by decontamination with nonabsorbable oral antibiotics decreases the chance of infectious complications and allows for primary anastomosis.
Fully obstructed patients cannot be prepped and must have a temporary colostomy.
Polyethylene glycol solution (CoLyte or GoLYTELY) is usually administered as 1 liter over 4 hours on the day before surgery. Nichols-Condon prep consists of 1 g neomycin sulfate and 1 g erythromycin base PO at 2:00, 3:00 and 11:00 pm the day before operation. Cefotetan 1-2 gm IV 30 minutes before operation.
Adjuvant chemotherapy is recommended for advanced colon lesions with the addition of pelvic radiation for advanced rectal tumors. Adjuvant therapy is reserved for locally advanced lesions (B2) or those with metastases to regional lymph nodes or distant organs (C1, C2, D).
Staging workup (CT of chest, abdomen and pelvis) usually is done postoperatively since it is unnecessary for very early lesions, and it does not change operative management. Pathologic staging of the tumor is done postoperatively by histologic examination of the surgical specimen.