Two randomized studies of rectal cancer surgeries using highly qualified surgeons were not able to show that laparoscopic procedures produce results equal to open ones.
The studies, published online in JAMA, each enrolled slightly under 500 patients at multiple sites, randomized them to open pelvic dissection or laparoscopic dissection, and selected surgeons with exceptional skills.
Both studies found rates of pathologist-determined adequate surgical dissection to be slightly lower for patients undergoing the laparoscopic procedures.
The North American study was carried out under the American College of Surgeons Oncology Group and led by Dr. James Fleshman of Baylor University Medical Center, Dallas. The study, which took place at 35 surgical centers, enrolled 486 patients with stage II or III rectal cancer within 12 cm of the anal verge who were randomized after neoadjuvant therapy to minimally invasive (n = 240) or open proctectomy (n=222) (JAMA. 2015;314:1346-55).
Success was measured by pathologic oncologic markers related to quality of the rectal specimen: a composite of circumferential radial margin greater than 1 mm, distal margin without tumor, and completeness of total mesorectal excision. A 6% noninferiority margin was chosen according to clinical relevance estimations for this patient group.
Successful resection occurred in 82% of laparoscopic resection cases (95% confidence interval, 76.8%-86.6%) and 87% of open cases (95% CI, 82.5%-91.4%). The results did not support noninferiority for laparoscopic procedures (P = .41).
The finding came as a surprise, Dr. Fleshman and colleagues wrote in their analysis, not least because of the skill level of the surgeons participating in the study. A group of “highly motivated, credentialed, expert laparoscopic rectal surgeons was ideal to test this hypothesis,” they wrote. Moreover, only 11% of patients assigned laparoscopy had to be converted to open procedures, “so the learning curve cannot be invoked to explain our results because conversion rates were reasonable.”
More likely, they wrote, “the technique itself, along with the current methodology available, must be questioned if motivated experts cannot produce a quality specimen defined by this novel combined metric.”
Proctectomy is always challenging, Dr. Fleshman and colleagues wrote, “and it can be even more difficult to work in the deep pelvis with in-line rigid instruments from angles that require complicated maneuvers to reach the extremes of the pelvis. It is possible that modification of instruments or a different platform such as robotics will improve efficacy of minimally invasive techniques.”
The Australian study, carried out by the Australasian Gastro-Intestinal Trials Group network and led by Dr. Andrew R. L. Stevenson of the University of Queensland and Royal Brisbane and Women’s Hospital, Brisbane, Australia, enrolled 475 patients with T1-3 rectal tumors less than 15 cm from the anal verge and randomized them to laparoscopic (n = 238) or open (n = 235) pelvic dissection. Half of patients had received radiotherapy before the operations. Some 26 surgeons operated at 24 sites in Australia and New Zealand. (JAMA. 2015;314:1356-63).
For this trial, successful resection was defined as complete total mesorectal excision, a clear circumferential margin of at least 1 mm, and a clear distal resection margin of 1 mm or more. The prescribed noninferiority margin for this patient group was 8%. As in the North American study, pathologists were blinded to the method of surgery.
Successful resection occurred in 194 patients (82%) in the laparoscopic group and 208 (89%) in the open surgery group, not reaching noninferiority for the laparoscopic approach (P = 0.38 for noninferiority). Conversion to open dissection occurred in 9% of the laparoscopy-assigned patients.
“Even though our trial was not designed to demonstrate whether one method of rectal dissection was superior to the other, the inability to establish noninferiority suggests that surgeons should be cautious when considering the suitability of a laparoscopic approach for a patient with rectal cancer,” Dr. Stevenson and colleagues wrote in their analysis.
“Subgroup analyses raise the possibility that laparoscopic surgery might be less successful than open surgery in patients who have received neoadjuvant therapy, have larger T3 tumors, or have higher BMIs. However, our study was underpowered to show significant differences in proportions of lower success rates for laparoscopic surgery vs. open surgery.”
The North American trial was funded by the National Cancer Institute, the American Society of Colon and Rectal Surgeons, the Society of American Gastrointestinal and Endoscopic Surgeons, and the Covidien Company. Dr. Fleshman reported no conflicts, while several coauthors disclosed financial relationships with surgical device manufacturers, including Covidien.
The Australasian trial was funded by the Colorectal Surgical Society of Australia and New Zealand and the National Health and Medical Research Council. No conflicts of interest were reported.