Staging of colorectal carcinoma

Astler-Coller modification of Dukes’ Classification (most commonly used classification)

Stage A: Limited to mucosa and submucosa. Nodes negative.

Stage BI: Extends into, but not through, muscularis propria; nodes negative.

Stage B2: Extends through muscularis propria; nodes negative.

Stage CI: Same as B1, except nodes positive.

Stage C2: Same as B2, except nodes positive.

TNM Classification (International standard)

TX: Tumor cannot be assessed.

T0: No tumor in specimen (prior polypectomy done).

Tis: Carcinoma in situ.

T1: Invades into submucosa.

T2: Invades into muscularis propria.

T3: Invades through muscularis propria.

T4: Invades adjacent organs or into free peritoneal cavity.

NX: Nodes cannot be assessed.

N0: No regional nodal metastasis.

N1: 1-3 nodes positive.

N2: More than 3 nodes positive.

N3: Central nodes positive.

MX: Presence of distant metastases cannot be assessed.

M0: No distant metastasis.

M1: Distant metastasis present.

Management of obstructing carcinomas of the left colon

Correct fluid deficits and electrolyte abnormalities. Nasogastric suction is useful, but it is not adequate to decompress the acutely obstructed colon.

The Hartmann procedure is indicated for distal descending and sigmoid colon lesions. This procedure consists of resection of the obstructing cancer and formation of an end colostomy and blind rectal pouch. The colostomy can be taken down and anastomosed to the rectal pouch at a later date.
Colon Cancer
Primary resection with temporary end colostomy and mucous fistula should be done for lesions of the transverse and proximal descending colon. This procedure consists of resection of the obstructing cancer and creation of a functioning end colostomy and a defunctionalized distal limb with separate stomas. The colostomy can be taken down and continuity restored at a later date.

An emergency decompressive loop colostomy can be considered for acutely ill patients. After four to six weeks, a hemicolectomy can be completed.

A primary anastomosis may be done in selected patients with a prepared bowel.

Management of obstructing carcinomas of the ascending colon

Correct fluid deficits, electrolyte abnormalities, and initiate nasogastric suction.

A right hemicolectomy with primary anastomosis of the terminal ileum to the transverse colon can be performed on most patients. A temporary ileostomy is rarely needed.

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.

Colorectal cancer is the second most common solid malignancy in adults and the second leading cause of cancer death in the US.

Clinical evaluation of colorectal cancer

Flexible sigmoidoscopy for screening is indicated for asymptomatic, healthy adults over age 50. All adults with anemia or guaiac positive stools should be evaluated for colorectal cancer; older adults (>40) should be evaluated even if other sources of bleeding have been found. Hemorrhoids and cancer can coexist.

Flexible sigmoidoscopy plus air contrast barium enema is adequate to evaluate the colon when the source of bleeding is thought to be benign anorectal disease.

Total colonoscopy should be performed for any adult with gross or occult rectal bleeding and no apparent anorectal source.

Left sided or rectal lesions are characterized by blood streaked stools, change in caliber or consistency of stools, obstipation, alternating diarrhea and constipation, and tenesmus.

Right sided lesions are characterized by a triad of iron deficiency anemia, a right lower quadrant mass, and weakness. Cancers occasionally present as a large bowel obstruction, perforation or abscess.

Laboratory evaluation

CBC with indices (hypochromic, microcytic anemia). Liver function tests may sometimes be elevated in metastatic disease.

Carcinoembryonic antigen (CEA) may be elevated in colorectal cancer, but it is a nonspecific test (also elevated in other malignancies, some inflammatory bowel disease, cigarette smokers, and some normal persons). It is valuable in monitoring the response to treatment and as a marker for recurrence or metastases, requiring adjuvant therapy. It should be measured prior to resection of the tumor and at intervals postoperatively.

Colorectal cancer is detected by total colonoscopy with biopsies. Barium enema may complement colonoscopy since BE shows the exact anatomic location of the tumor. A chest X-ray should be done to search for metastases to the lungs.