STOCKHOLM – Laparoscopic surgery offers the same radical resection for noninvasive rectal cancer as does open surgery, according to short-term outcomes of the randomized, noninferiority phase III COLOR II trial.
The circumferential resection margin, described as the most important parameter for rectal cancer surgery, was 1.3 cm after laparoscopic and open surgery (P = .16). The distal margin was similar at 3.6 cm (P = .68).
Dr. H. Jaap Bonjer
The proximal margin was 17.0 cm in the laparoscopic group and 19.0 cm in the open group. The difference was statistically significant (P less than .001), but "clinically, totally irrelevant since a 17-cm margin is wide enough for a safe tumor resection," lead author Dr. H. Jaap Bonjer said at the European Multidisciplinary Cancer Congress.
COLOR II (Colorectal Cancer Laparoscopic or Open Resection) sought to answer whether laparoscopic total mesorectal excision is as oncologically safe as open surgery is. Removing the entire mesorectum, or fatty tissue around the rectum, is important because the radial spread of rectal cancer is more prominent than is longitudinal spread, explained Dr. Bonjer of the surgery department at Vrije University Medical Centre, Amsterdam.
Researchers at 30 centers in eight countries, including Canada, randomized 1,103 patients with a single rectal carcinoma within 15 cm of the anal verge, staged T1, T2, or T3 with a margin to the endopelvic fascia greater than 2 mm, to laparoscopic or open surgery. The analysis included 699 patients in the laparoscopic arm and 345 in the open surgery arm.
The technically demanding nature of laparoscopic surgery resulted in a longer operating time than with open surgery (median 240 minutes vs. 188 minutes, P less than .001), but blood loss was cut in half (median 200 mL vs. 400 mL, P less than .001), Dr. Bonjer said.
The number of lymph nodes harvested was similar at 13 in the laparoscopic group and 14 in the open group.
The overall positive resection margin rate, defined as less than 2 mm, was 9% in the laparoscopic group and 10% in the open group (P = .078), Dr. Bonjer said at the joint congress of the European Cancer Organization, the European Society for Medical Oncology, and the European Society for Radiotherapy and Oncology.
Subgroup analyses showed similar positive resection margin rates in the upper rectum (10% vs. 9%, P = .92) and middle rectum (9% vs. 3%, P = .073), but a significantly better rate in the lower rectum after laparoscopic surgery at 9% vs. 21% after open surgery (P = .013).
The laparoscopic group also had improved postoperative recovery compared with the open group including a shorter time to first bowel movement (2.9 days vs. 3.7 days, P = .001), time to intake of 1 liter of fluid (2.6 days vs. 2.8 days P = .006) and hospital stay (11.9 days vs. 12.1 days, P = .037), he said.
Anastomotic leakage occurred in 7% of patients after laparoscopic surgery and 6% after open surgery (P = .63). One-third of patients had a diverting ileostomy.
Mortality rates within 28 days after surgery did not differ between the laparoscopic and open groups (1.1% vs. 1.7%, P = .41), nor did morbidity (39.5% vs. 36.5%, P = .28), Dr. Bonjer said.
Dr. Peter Naredi, invited discussant and president of the European Society of Surgical Oncology, said COLOR II was very well performed, and that the large number of laparoscopic patients "will make a huge impact on the results of how good laparoscopic surgery is versus open surgery" when added to the current database.
He highlighted a meta-analysis published this spring of six randomized trials enrolling 1,033 patients that showed no difference between the two techniques with regard to number of lymph nodes harvested, involvement of the circumferential resection margin, 3-year-overall survival, and disease-free survival (Int. J. Colorectal. Dis. 2011;26:415-21).
Dr. Naredi, chair of surgery at Umeå (Sweden) University, expressed concern, however, about the 21% positive resection margin rates in the lower rectum for the open group, and said this would likely convert into differences in local recurrence between the two groups. He also stressed the importance of standardization when evaluating multimodal treatments, and pointed out that preoperative radiotherapy was used in 72% of the lower rectal cancer patients treated with laparoscopy and only 63% treated with open surgery.
Ethicon EndoSurgery supported the trial. No individual disclosures were presented.