An Update on Laparoscopic Resection for Rectal Cancer

Abstract

Laparoscopic surgery has proved to be a safe and feasible option in the surgical treatment of colon cancer, with better short-term results and similar oncologic outcomes when compared to conventional surgery. However, there has been some skepticism towards the use of the laparoscopic approach to treat rectal cancer, particularly regarding long-term oncologic outcomes.If these are not proven equivalent or better than the ones open surgery has to offer, the short-term advantages will not matter. A central setback in the acceptance of laparoscopy as a first-line treatment for rectal cancer is the lack of prospective randomized clinical trials with a large number of patients addressing specifically the comparison between laparoscopy and laparotomy and clearly stating the advantage of laparoscopy over open surgery in terms of oncologic outcomes. The bulk of available data comes from relatively small-randomized control studies and larger non-randomized case series, since most of the published multicenter trials regarding colorectal cancer did not recruit patients with rectal cancer because the procedure is technically demanding. The heterogeneity of protocols is an important aspect to consider when drawing conclusions. Follow-up periods varied widely. Exclusion criteria can lead to selection bias.Factors such as the lack of standardization of the surgical technique, type of procedure, localization and stage of the tumor, presence or absence of neoadjuvant and adjuvant radiochemotherapy, patient’s characteristics and surgeon’s experience can influence outcomes regardless of the surgical approach, and have to enter the equation as results are interpreted. Oncologic safety can be measured by conversion rate, surgical margins positivity, number of LN harvested, local recurrence and survival rates, and that was the reason why those parameters were analyzed in this review. Conversion rates ranged widely, from 0% to values as high as 34%, with more recent studies reporting lower rates. This could be due to heterogeneity of clinical trials, different phases of the learning curve, and better patient selection. The most reported reasons forconversion were bulky tumors and obesity.Conversion seems to have a negative impact on surgical outcomes, but some inconsistent results have been published and this issue is not yet fully understood. Careful preoperative assessment of risk factors for conversion can help prevent it. MRC CLASICC initially reported alarming results on circumferential surgical margins. However, 3-year outcomes did not show any impact on local recurrence. Although other studies also reported lower rates of margin clearance associated with laparoscopy, these were not statistically significant. Moreover, most meta-analyses showed no difference between surgical approaches. The same happened with LN count and local recurrence rates, which were similar in laparoscopic and open surgery. Most follow-ups are relatively shorter and long-term survival has been published in very few studies, not allowing definitive conclusions. The survival rates reported have been similar and none of the studies found a clear domain of one surgical technique over the other in this regard.