Minimally invasive surgical approaches inferior to open resection for rectal cancer

The use of minimally invasive laparoscopic resection did not improve outcomes compared with open resection for patients with rectal cancer, according to the results of two randomized trials.

Surgery remains the primary strategy to treat rectal cancer. Thus, researchers sought to determine whether laparoscopic procedures — generally believed to produce better outcomes than open resections — were noninferior to open procedures. Due to anatomical constraints that may lead to inadequate resection, laparoscopic rectal resection may not be preferable.

Two randomized, multicenter noninferiority trials — both published in JAMA — compared laparoscopic resection and open rectal cancer resection for adequacy of cancer clearance.

ACOSOG Z6051

The ACOSOG Z6051 randomized clinical trial — led by James Fleshman, MD, FACS, FACRS, chair of the department of surgery at Baylor University Medical Center — included 486 patients with stage II or stage III rectal cancer within 12 cm of the anal verge. Researchers randomly assigned patients to laparoscopic resection (n = 243) or open resection (n = 243).

Researchers set a 6% noninferiority margin according to clinical relevance estimation. A composite of circumferential radial margin greater than 1 mm, distal margin without tumor and completeness of total mesorectal excision served as the primary outcome measures of efficacy.

Based on data from evaluable patients (laparoscopic, n = 240; open, n = 222), the researchers considered 81.7% (95% CI, 76.8-86.6) of laparoscopic resections and 86.9% (95% CI, 82.5-91.4) of open resections to be successful according to the outcome measures. These findings did not support noninferiority (difference = –5.3%; P = .41)

Patients underwent low anterior resection (76.7%) or abdominoperineal resection (23.3%). Conversion to open resection occurred among 11.3% of patients.

Patients assigned to laparoscopic resection experienced significantly longer operating times (mean, 226.2 vs. 220.6 minutes; mean difference, 45.5 minutes; P < .001). However, length of stay (7.3 vs. 7 days), readmission within 30 days (3.3% vs. 4.1%) and severe complication (22.5% vs. 22.1%) did not significantly differ between the two groups.

The quality of the total mesorectal excision specimen in the 462 analyzed surgeries was complete (77%) and nearly complete (16.5%) in 93.5% of cases.

Ninety percent of the overall group had negative circumferential radial margins (laparoscopic, 87.9%; open resection, 92.3%) and negative distal margins occurred in more than 98% of patients regardless of surgery type.

“Among patients with stage II or stage III rectal cancer, the use of laparoscopic resection compared with open resection failed to meet the criterion for noninferiority for pathologic outcomes,” Fleshman and colleagues wrote. “Pending clinical oncologic outcomes, the findings do not support the use of laparoscopic resection in these patients.”

ALaCaRT

The Australasian Laparoscopic Cancer of the Rectum (ALaCaRT) phase 3 randomized clinical trial — led by Andrew R.L. Stevenson, MBBS, FRACS, associate professor of surgery at University of Queensland in Brisbane, Australia — included 475 patients with T1 to T3 rectal adenocarcinoma less than 15 cm from the anal verge. Researchers randomly assigned patients to open laparotomy and rectal resection (n = 237) or laparoscopic rectal resection (n = 238).

The ALaCaRT trial set a noninferiority boundary of –8%. The researchers defined a successful resection as total mesorectal excision, a clear circumferential margin of at least 1 mm, and a clear distal resection margin of at least 1 mm.

Eighty-two percent of patients assigned laparoscopic resection (n = 194) and 89% assigned open resection (n = 208) achieved a successful resection, which did not reach the benchmark for noninferiority (risk difference = –7%; P = .38)

Ninety-three percent of patients undergoing laparoscopic resection (n = 222) and 97% of patients undergoing open resection (n = 228) had clear circumferential resection margins (risk difference = –3.7%; P = .06).

Ninety-nine percent of patients in both groups had clear distal margins (laparoscopic, n = 236; open resection, n = 234).

Total mesorectal excision was complete in 87% (n = 206) of the laparoscopic resection group and 92% (n = 216) of the open resection group (risk difference = –5.4; P = .06).

Patients in the laparoscopic surgery group had a conversion rate to open resection of 9%.

“Although the overall quality of surgery was high, these findings do not provide sufficient evidence for the routine use of laparoscopic surgery,” Stevenson and colleagues wrote. “Longer follow-up of recurrence and survival is currently being acquired.”

Questions remain

Despite advances in colorectal surgery, continued research and clinical trials are needed to fully understand the risk profiles of minimally invasive procedures, Scott A. Strong, MD, chief of the division of surgery–surgical oncology at Northwestern University’s Feinberg School of Medicine, and Nathaniel J. Soper, MD, chair of the department of surgery at Northwestern University’s Feinberg School of Medicine, wrote in an accompanying editorial.

“Although the surgical management of patients with rectal cancer and diverticulitis has greatly improved, many questions persist and new ones continually arise that can be answered only with well-designed, rigorously conducted clinical trials,” Strong and Soper wrote. “The utility of less intrusive strategies and minimally invasive approaches will undoubtedly expand as technologies evolve, but they must be responsibly incorporated into surgical practice based on evidence rather than subjective reasons.” – by Cameron Kelsall

References:

Fleshman J, et al. JAMA. 2015;doi:10.1001/jama.2015.10529.

Stevenson AR, et al. JAMA. 2015;doi:10.1001/jama.2015.12009.

Strong SA and Soper NJ. JAMA. 2015;doi:10.1001/jama.2015.11454.

Disclosure: Fleshman reports no relevant financial disclosures. Please see the full study for a list of all relevant disclosures made by the researchers of the ACOSOG Z6051 trial. The researchers of the ALaCaRT trial report no relevant financial disclosures. Strong and Soper report no relevant financial disclosures.