Operative Issues
Operative Techniques – Colon
Recommendation: Laparoscopic resection should follow standard oncologic principles: proximal ligation of the primary arterial supply, adequate proximal and distal margins, and appropriate lymphadenectomy (Level I evidence, Grade A recommendation)
Existing guidelines for colon and rectal cancer surgery have established levels of evidence and grades of recommendation for the following: proximal and distal colonic resection margins (determined by the area supplied by the primary feeding arterial vessel(s)); lymphadenectomy with a minimum of 12 lymph nodes harvested; and ligation of the named feeding vessel at its origin. The two adequately powered randomized trials of laparoscopic colectomy for curable colon cancer followed these oncologic principles and showed no significant difference in proximal and distal bowel margins, number of lymph nodes retrieved, and, in the Clinical Outcomes of Surgical Therapy Study Group (COST) trial, perpendicular length of the primary vascular pedicle.
These recommendations determine which portions of the procedure may be performed intracorporeally or extracorporeally. In a patient with a normal body mass index undergoing right colectomy it is often feasible to ligate the base of the ileocolic pedicle via a periumbilical incision. In a heavier patient, this might best be performed intracorporeally. For all other vessels, the origin of the vessel will generally need to be ligated intracorporeally unless a larger incision such as used for hand-assisted procedures permits safe access to the base of the vessels. Inability to comply with oncologic principles should prompt conversion to an open operation.
Operative Techniques – Rectum
Recommendation: Laparoscopic resection for rectal cancer should follow standard oncologic principles: adequate distal margin, ligation of the base of the superior rectal/inferior mesenteric artery, and mesorectal excision (Level II evidence, Grade B recommendation)
Operative guidelines for open rectal surgery have been established with levels of evidence and grades of recommendation for techniques relevant only to the rectum. These include a distal margin of 1 to 2 cm, removal of the blood supply and lymphatics up to the origin of the superior rectal artery (or inferior mesenteric artery if indicated), and appropriate mesorectal excision with radial clearance.
Laparoscopic resection of rectal cancer has not been evaluated in a randomized trial. Prospective and retrospective case series have suggested that the procedure is feasible in carefully selected patients. The confines of the pelvis confer additional challenges on the laparoscopic approach, particularly for distal rectal tumors. The ability to perform an oncologically adequate laparoscopic resection for rectal cancer will depend on tumor factors such as size, proximal or distal location, and patient factors including anatomy of the pelvis (narrow or wide), obesity, bulky uterus, and effect of prior radiation on tissue planes. Inability to comply with oncologic principles should prompt conversion to an open operation.
Contiguous Organ Attachment
Recommendation: Open approach is required if a laparoscopic en-bloc resection for a T4 lesion cannot be safely performed. (Level II evidence, Grade B recommendation)
Current guidelines for open colon and rectal cancer surgery recommend en bloc resection to manage locally advanced adherent colorectal tumors. Histologically negative margins achieved with en bloc resection are considered curative. Preoperative studies such as CT scan may suggest a bulky tumor invasive into an adjacent organ and guide the decision to perform an open resection. A known T4 colonic cancer may prompt an open approach. The ability to perform en bloc resection laparoscopically is dependent on the structure to which the tumor is adherent, in addition to surgeon skill and experience. When the goal is curative resection, intraoperative discovery of a T4 lesion requires conversion, unless the surgeon is capable of properly resecting the lesion en bloc.
Tumor Perforation and the "No-Touch Technique"
Recommendation: Perforation of the tumor should be avoided. (Level III evidence, Grade C recommendation)
Excessive force or use of instruments not suited to handling of the bowel may cause inadvertent perforation. Inadvertent perforation results in increased local recurrence rates and a significant reduction in 5-year survival. Thus, although the "no-touch technique" (with early ligation of vessels) is not specifically recommended, avoidance of perforating the tumor with handling is advocated.
For open resection of curable colorectal carcinoma, the value of the no-touch technique, with early ligation of the vascular supply, has not been proven. In laparoscopic resection, some surgeons employ a medial-to-lateral approach with early ligation of the mesenteric vessels. No oncologic benefit of this approach has been shown.
Prevention of Wound Implants
Recommendation: The extraction incision should be mechanically protected during specimen retrieval. (Level II evidence, Grade C recommendation)
Wound implants, or recurrence of cancer, have been reported at both the extraction site incision and the port sites. The phenomenon has prompted extensive research.
Most measures suggested to prevent wound implants have been generated by in vitro and in vivo animal models, not clinical practice. The results of gasless laparoscopy are inconsistent, as some studies have shown a decrease in port site metastases, yet others have been unable to confirm this. Low insufflation pressures may result in reduced tumor growth. Carbon dioxide may enhance tumor implantation and growth but is the safest gas to work within the clinical arena. Helium may reduce the rate of wound implants but is not used clinically. Wound excision has been shown to both decrease and to increase the rate of wound recurrence.
Certain experimental findings have resulted in simple modifications of the laparoscopic approach. Aerosolization of tumor implants occurs in experimental models employing large numbers of tumor cells, although others doubt its role in tumor implants. As it is easy to desufflate the pneumoperitoneum via the trocars rather than via the incision, some experts advocate this practice. Related to this is the description of gas leakage along loosely fixed trocars (the "chimney effect") which was related to increased tumor growth in one study. Thus fixation of trocars or use of trocars with modifications preventing slippage is widely used. Reductions in port site metastases have been shown in animal models following irrigation of the peritoneal cavity and/or port site incisions with solutions such as povidone-iodine, heparin, methotrexate, cyclophosphamide, taurolidine and 5-fluorouracil. Although these models employ supra-normal numbers of cancer cells, a consensus panel of the European Association of Endoscopic Surgery reported that half the expert panel irrigated the port sites with either povidone-iodine, distilled water or tauroline and all the panel protected the extraction site and/or placed the specimen in a plastic bag prior to extraction.
The most significant impact on the incidence of port site metastasis has been that of experience and the development of laparoscopic techniques that permit an oncologic resection, identical to the open one, to be performed. Initial reports of port sites metastases ranging from 2-21% have dropped to less than 1% in large case series and randomized trials. This is similar to the rate for open colorectal cancer resection. In the COST study and Lacy's study the rates were 0.5% and 0.9% respectively. Surgical experience is considered the most important factor in the prevention of incisional implants.
In summary, experimental animal models have shown a reduction in wound implants if the wound is protected or treated with a tumoricidal substance. There is no consensus on the nature of the irrigant, but diluted povidone-iodine and distilled water were the most commonly used among experts. In the operating room, in addition to wound protection, other commonly used techniques are fixation of trocars, evacuation of the pneumoperitoneum via the ports, and wound irrigation. Wound implants should be kept at a rate less than 1% by correct oncologic technique and experience.
