The mainstay for the treatment of Stage I colorectal cancer is surgery. The goals of surgery are to:
- Remove the cancer completely with clear margins.
- Remove adjacent draining lymph node.
- Avoid excessive disruption or spillage of tumor cells.
- Reconstruct the bowel, if possible, in order to achieve intestinal continuity and normal or near normal bowel function postoperatively.
The type of surgery depends on a variety of factors, including: the location of the tumor, the presence of other associated cancers or polyps, the stage of the cancer; the risk of development of other colon cancer in the future; the patient’s preference. The method of reconstruction of the colon can vary. Some surgeons use manual suturing either in one or two layers, others prefer one of various stapling techniques.
|A variety of types of colorectal surgeries are possible depending on where the cancer occurs. The surgical techniques for colon cancer differs signficantly from the surgical techniques for rectal cancer. At Johns Hopkins we have a team of surgeons who specialize in colon and rectal cancer surgery ensuring that patients get the most advanced, effective, and safe treatments.|
Please choose the location of your cancer to view the corresponding surgical techniques:
Colorectal resection, including regional lymph nodes, is based on the blood supply to the bowel (Figure 20).
|Figure 20. Arterial blood supply to the colon.|
Surgical Treatment of Stage I Colon Cancer
A right hemicolectomy (Figure 21) is the surgical procedure performed for patients with cancer between the cecum and ascending colon.
|Figure 21. Right hemicolectomy with ileocolic anastomosis. |
A transverse colectomy (Figure 22) is performed for tumors in the transverse colon. The middle colic artery is ligated and the ascending and descending colon are anastomosed.
|Figure 22. Transverse colectomy with anastomosis of ascending and descending colon. |
Extended right colectomy is performed in cases in which the cancer is located in the proximal or mid transverse colon (Figure 23). This resection requires removal of the terminal ileum, cecum, ascending colon, hepatic flexure and a portion of the transverse colon.
|Figure 23. Extended right colectomy with ileocolic anastomosis. |
Left hemicolectomy (Figure 24) is the procedure for tumors of the descending colon. The left colic artery is ligated, the splenic flexure and descending colon removed and the transverse and upper sigmoid colon joined (anastomosed).
|Figure 24. Left hemicolectomy with transverse and sigmoid colon anastomosis. |
Sigmoid colectomy removes tumors of the sigmoid colon (Figure 25). The upper rectum and descending colon are joined (anastomosed).
|Figure 25. Sigmoid colectomy with anastomosis of descending colon and upper rectum. |
Surgical Treatment of Stage I Rectal Cancer
The surgical management of rectal cancer can be particularly complicated, depending on the location of the tumor. There are a variety of surgical procedures that are available to patients with rectal cancer ranging from local excision to radical abdominoperineal resection. Accurate preoperative staging determining depth of invasion and lymph node involvement is essential in selection of the appropriate operative procedure. CT or MRI and endorectal ultrasound are diagnostic tests used for staging of the tumor.
The three options for management of rectal cancers include:
- Local excision
- Restorative anterior or low anterior resection
- Abdominal perineal resection with permanent colostomy
Local excision also known as transanal excision for rectal cancer is reserved for selected early lesions of the rectum. In this case, the surgeon removes full thickness of the rectum only without harvesting any lymph nodes. In general, local excision may be offered for T1 rectal cancers (i.e. cancer has only spread to submucosa), small tumors (less than 3–4 cm in diameter) within 6–8 cm of the anal verge, and with limited circumferential involvement (less than one third of rectal circumference). Tumors should be moderately- to well-differentiated and be T1 on transrectal ultrasound. A 1-cm margin of grossly normal mucosa beyond the edge of the tumor is ideal, although 5-mm is acceptable. A full thickness rectal wall excision to the perirectal fat layer is performed. Local excision reduces perioperative complications and preserves anorectal, bladder, and sexual function. Studies have demonstrated about a 90% recurrence-free survival rate in patients with T1 well–to–moderately differentiated rectal tumors without venous or lymph vessel invasion.
Local excision may not be recommended for cancers that have worrisome features such as poorly differentiated or lymphovascular invasion since such features suggest a higher likelihood of nodes involvement and more extensive procedures such as a low anterior resection or an abdomino-perineal resection may be needed.
The low anterior resection is suitable for lesions located in the upper two-thirds of the rectum. This sphincter-sparing operation can be performed for cancers in the middle and lower third of the rectum with low coloanal anastomosis at the level of the pelvic floor (Figure 26).
|Figure 26. Low anterior resection for tumors in the upper two thirds of the rectum. A, Temporary colostomy; B, subsequent colorectal anastomosis; C, restoration of GI tract continuity. |
Colorectal anastomosis or coloanal reconstructions are alternatives to permanent colostomy. Construction of a colon J-pouch creates a neorectal reservoir that can reduce frequency and urgency of bowel movements and nocturnal bowel movements in selected cases (Figure 27).
|Figure 27. A, Low anterior resection; B,C, coloanal anastomosis; D, j pouch construction creating a reservoir. |
These radical “transabdominal” resections are recommended for most cancers at risk for recurrence (higher than stage T1 or poorly differentiated with lymphatic or vascular involvement). The selection of surgical procedure should be guided toward the prevention of pelvic recurrence. Total mesorectal excision with a low anterior resection or an abdominoperineal resection is the optimal surgical procedure for rectal cancer. Total mesorectal excision removes the rectal mesentery as an intact unit. This reduces local recurrence along with preserving sexual function, urinary function, and continency.
Abdominoperineal resection is used when the lesion is in the lowest part of the rectum (Figure 28) typically involving the anal musculature. A colostomy allows for drainage of waste through an opening in the abdominal wall.
|Figure 28. Abdominoperineal resection with colostomy. |
Treatment for Advanced (Unresectable) Rectal Cancer
For patients with obstructive unresectable rectal cancer, endoscopic therapy using the neodymium-yttrium-aluminum-garnet (Nd:YAG) laser is an alternative to recanalize the rectal lumen. Electrofulguration using a heater probe has also been used for palliative therapy.
Another approach for patients who are poor surgical candidates is photodynamic therapy(PDT). In this procedure, patients are sensitized with a hematoporphyrin derivative, which is taken up preferentially by the tumor cells. At this point, phototherapy is performed using a laser beam applied through a flexible optical fiber directed at the tumor. The laser sensitizes the protoporphyrin ultimately inducing apoptosis (programmed cell death) essential killing the tumor cells. This technique is still considered experimental.
Complications associated to endoscopic therapy with Nd:YAG laser are bleeding and perforation.