July’s paper of the month looks at the short-term results of the COLRAR trial - a multicenter randomized controlled trial comparing laparoscopic and robotic-assisted surgery for middle or low rectal cancer.
Comparison of Laparoscopic Versus Robot-Assisted Surgery for Rectal Cancers: The COLRAR Randomized Controlled Trial
Park JS, Lee SM, Choi GS, Park SY, Kim HJ, Song SH, Min BS, Kim NK, Kim SH, Lee KY.
Annals of Surgery 2023 Jul 1; 278(1): 31-38. doi: 10.1097/SLA.0000000000005788. Epub 2023 Jan 3.
What is known about the subject?
Laparoscopic colectomy for colon cancer has been shown by several multicenter randomized controlled trials (RCTs) and meta-analyses [1] to have faster postoperative recovery and similar long-term oncologic outcomes compared with open surgery. The role of laparoscopic surgery for rectal cancer, on the other hand, is still controversial. Laparoscopic total mesorectal excision (TME) for rectal cancer is technically more challenging than laparoscopic colectomy for colon cancer. These technical challenges include difficulties in pelvic exposure, precise rectal dissection in the narrow pelvis, and preservation of anal sphincter and pelvic autonomic nerves. Consequently, the ACOSOG Z6051 and ALaCaRT RCTs failed to demonstrate the noninferiority of laparoscopic TME compared with open surgery [2,3].
One of the most significant technical advances in the field of minimally invasive colorectal surgery in the recent decade is the introduction of the robotic surgical system. Robotic surgery can essentially overcome the technical disadvantages of conventional laparoscopic TME in terms of visualization and maneuverability, which may enable surgeons to perform precise dissection easily in the narrow pelvis. However, in the multicenter ROLARR trial comparing robotic-assisted and laparoscopic surgery for rectal cancer published in 2017, no significant benefits in terms of conversion rate and pathologic outcomes were identified in the robotic surgery group [4]. Further studies have been launched to further define the role of robotic TME for rectal cancer.
What does the study add?
The COLRAR (Comparison Of Laparoscopic versus Robot-Assisted surgery for Rectal cancer) trial was a multicenter RCT in Korea comparing robotic and laparoscopic TME in patients with middle and low rectal cancer [5]. All operations were performed by experienced and high-volume surgeons. The primary outcome was the completeness of TME. The RCT was prematurely terminated because of poor patient accrual. Between July 2011 and February 2016, 295 patients (55% of the targeted sample size) were recruited; 151 were randomized to the robotic group and 144 to the laparoscopic group. The rates of complete TME were not different between the groups (80.7% in the robotic group vs 77.1% in the laparoscopic group, P = 0.567). Pathologic outcomes including the circumferential resection margin (CRM) positivity rates and the number of lymph nodes retrieved were also not different between the groups. In a subgroup analysis, the CRM positivity rate in the robotic group was significantly lower than the laparoscopic group among those patients who had neoadjuvant chemoradiotherapy (0% vs 8.2%, P = 0.034). For the recovery parameters, the duration of analgesic use was significantly shorter in the robotic group. There was no difference in the postoperative complication rate between the groups. Quality of life and urosexual functional outcomes also did not differ between the groups.
Implications for colorectal practice
This study showed that when compared with conventional laparoscopic surgery, robotic TME performed by experienced surgeons did not significantly improve the quality of TME in patients with middle or low rectal cancer. However, in a subgroup analysis, the CRM positivity rate in the robotic TME group was found to be significantly lower than the laparoscopic group among those patients who had neoadjuvant chemoradiotherapy. This observation might indicate a possible benefit of robotic TME in such difficult cases. The ROLARR trial also demonstrated some benefits of robotic surgery over laparoscopic surgery in selected subgroups such male or obese patients, in terms of conversion rate. Further studies are needed to focus on technically challenging and difficult cases to verify any real benefits of robotic TME. This study was prematurely terminated because of poor patient accrual, and hence the results should be interpreted with caution because the study was obviously underpowered. In the future, a comprehensive analysis by pooling the data of different RCTs may provide a better and stronger conclusion regarding the role of robotic TME for middle and low rectal cancer.
References
- Bonjer HJ, Hop WC, Nelson H, Sargent DJ, Lacy AM, Castells A, Guillou PJ, Thorpe H, Brown J, Delgado S, Kuhrij E, Haglind E, Pahlman L; Transatlantic Laparoscopically Assisted vs Open Colectomy Trials Study Group. Laparoscopically assisted vs open colectomy for colon cancer: a meta-analysis. Arch Surg 2007; 142: 298-303.
- Fleshman J, Branda M, Sargent DJ, Boller AM, George V, Abbas M, Peters WR Jr, Maun D, Chang G, Herline A, Fichera A, Mutch M, Wexner S, Whiteford M, Marks J, Birnbaum E, Margolin D, Larson D, Marcello P, Posner M, Read T, Monson J, Wren SM, Pisters PW, Nelson H. Effect of Laparoscopic-Assisted Resection vs Open Resection of Stage II or III Rectal Cancer on Pathologic Outcomes: The ACOSOG Z6051 Randomized Clinical Trial. JAMA 2015; 314: 1346-1355.
- Stevenson AR, Solomon MJ, Lumley JW, Hewett P, Clouston AD, Gebski VJ, Davies L, Wilson K, Hague W, Simes J; ALaCaRT Investigators. Effect of Laparoscopic-Assisted Resection vs Open Resection on Pathological Outcomes in Rectal Cancer: The ALaCaRT Randomized Clinical Trial. JAMA 2015; 314: 1356-1363.
- Jayne D, Pigazzi A, Marshall H, Croft J, Corrigan N, Copeland J, Quirke P, West N, Rautio T, Thomassen N, Tilney H, Gudgeon M, Bianchi PP, Edlin R, Hulme C, Brown J. Effect of Robotic-Assisted vs Conventional Laparoscopic Surgery on Risk of Conversion to Open Laparotomy Among Patients Undergoing Resection for Rectal Cancer: The ROLARR Randomized Clinical Trial. JAMA 2017; 318: 1569-1580.
- Park JS, Lee SM, Choi GS, Park SY, Kim HJ, Song SH, Min BS, Kim NK, Kim SH, Lee KY. Comparison of Laparoscopic Versus Robot-Assisted Surgery for Rectal Cancers: The COLRAR Randomized Controlled Trial. Ann Surg 2023; 278: 31-38.