Rectal Cancer

Concept Of Surgery For Rectal Cancer

Surgery is the most important treatment for rectal cancers. The presently accepted oncological concept is total mesorectal excision (TME), which is removal of the rectum along with the fat surrounding it and the blood vessels supplying it. This would include all the lymph nodes draining rectum. As opposed to blunt dissection of rectum, TME has been shown to reduce the local recurrence significantly. The TME specimen should have specific macroscopic characters. The best measure of the quality is the clear circumferential and cut margins, and the number of harvested lymph nodes (>12).

Depending on the location of the tumor within the rectum three types of surgeries can be performed:

1. Abdomino-Perineal Resection (APR)– This procedure is performed when it is not feasible to preserve anal sphincter due to involvement or being very close to tumor. This involves resection of sigmoid colon along with rectum and anal canal. A permanent colostomy is made.

2. Anterior Resection (AR)– This is the surgery offered to cancers above the peritoneal reflection of rectum. Colon along with upper portion of rectum are resected Remnant of colon is anastomosed to the remnant of rectum.

3. Low Anterior Resection (LAR)– This surgery is performed when the disease involves rectum bellow the peritoneal reflection of rectum. This can per performed provided there is at least 1 cm clear margin.

4. Ultra Low Anterior Resection– This procedure can be performed when the disease reaches upto 2 cm above the dentate line. In this procedure entire rectum is removed with preservation of sphincter. This coloanal anastomosis may be considered if the margins are too close.

Minimal Access Cancer Surgery (Macs) For Rectum The Evidence

Pelvis is a narrow space containing rectum, urinary bladder, prostate and seminal vesicles in men. In women the uterus and adnexa accompany the rectum. The pelvic nerves which are important for bowel, bladder and sexual function also run in the pelvis. The close packing of organs along with poor visibility in the pelvis during open procedure makes it difficult to perform TME. Laparoscopy solves many of these problems for the surgeons. The magnified view offered by laparoscopy can help in better visualization of pelvic structures and better preservation of them along with precise dissection of the disease with better oncological outcomes. Laparoscopy also offers other potential benefits like reduced blood loss, less postoperative pain, faster recovery and lower morbidity. The evidence available today is from small randomized trials which have compared open with laparoscopy. There are some meta-analysis (grouped analysis) of these studies which have suggested that laparoscopic TME is feasible and safe. The CLASSIC trial which was a UK based colorectal cancer trial included rectal cancer patients who underwent rectal resection. This study did not find any difference in bladder function between the two groups, however, sexual function was slightly worse in laparoscopic group. The authors attributed this to better quality of TME in laparoscopy. This study also had a higher number of circumferential margin positivity among laparoscopic low anterior resection cases which was attributed to higher technical skills needed to perform this surgery. However, survival analysis at 3 years did not show any difference in the survival between the two groups. Cochrane database which is a large database of diseases centered in UK, has analysed the data on rectal cancer surgeries and published in 2006. They found no difference in the lymph nodal yield and margin positivity between laparoscopic and open rectal surgeries. They also found the survival statistics to be similar between the groups.

Recommendation

The presently available evidence is strong enough to call laparoscopic rectal cancer surgery an oncologically safe procedure and is comparable to open procedure in oncological outcomes along with all the advantages of MACS. Careful case selection is recommended.

Pitfalls

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TME is essential component of rectal cancer surgery. There is a risk of coning during laparoscopic surgery as the surgeon approaches the levator ani muscle. This should be avoided all cost.

References

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Guillou PJ, Quirke P, Thorpe H, et al. Short-term endpoints of conventional versus laparoscopic assisted surgery in patients with colorectal cancer (MRC CLASSIC trial): multicentre, randomized controlled trial. Lancet2005; 365: 1718-26.

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Jayne DG, Guillou PJ, Thorpe H et al. for the UK MRC CLASICC Trial Group. Randomized trial of laparoscopic-assisted resection of colorectal carcinoma: 3-year results of the UK MRC CLASICC Trial Group. J Clin Oncol2007; 25: 3061-8.

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Breukink S, Pierie J, Wiggers T. Laparoscopic versus open total mesorectal excision for rectal cancer. Cochrane Database Syst Rev2006: CD005200.

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Braga M, Frasson M, Vignali A, et al. Laparoscopic resection in rectal cancer patients: outcome and cost-benefit analysis. Dis Colon Rectum2007; 50: 464-71.

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Araujo SE, da Silva eSousa AH Jr, de Campos FG, et al. Conventional approach x laparoscopic abdominoperineal resection for rectal cancer treatment after neoadjuvant chemoradiation: results of a prospective randomized trial. Rev Hosp Clin Fac Med Sao Paulo2003; 58: 133-40.

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Zhou ZG, Hu M, Li Y, et al. Laparoscopic versus open total mesorectal excision with anal sphincter preservation for low rectal cancer. Surg Endosc 2004; 18: 1211-15.

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Ng SS, Leung KL, Lee JF, et al. Laparoscopic-assisted versus open abdominoperineal resection for low rectal cancer: a prospective randomized trial. Ann Surg Oncol2008; 15: 2418-25.

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Gao F, Cao YF, Chen LS. Meta-analysis of short-term outcomes after laparoscopic resection for rectal cancer. Int J Colorectal Dis2006; 21: 652-6.

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Aziz O, Constantinides V, Tekkis PP, et al. Laparoscopic versus open surgery for rectal cancer: a metaanalysis. Ann Surg Oncol2006; 13: 413-24.

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Kim NK, Aahn TW, Park JK, et al. Assessment of sexual and voiding function after total mesorectal excision with pelvic autonomic nerve preservation in males with rectal cancer. Dis Colon Rectum2002; 45: 1178-85.

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Jayne DG, Brown JM, Thorpe H, et al. Bladder and sexual function following resection for rectal cancer in a randomized clinical trial of laparoscopic versus open technique. Br J Surg2005; 92: 1124-32.

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Hermanek P, Hermanek P, Klimpfinger M, et al. The pathological assessment of mesorectal excision: implications for further treatment and quality management. Int J Colorectal Dis2003; 18: 335-41.

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