MADISON, WIS. – Laparoscopic resection of hepatic colorectal cancer offered short-term benefits over open resection and equivalent cancer control in a propensity matched cohort study of 173 patients.
"The oncologic outcomes are really not affected at all by the performance of the minimally invasive procedure," lead author Robert Cannon said at the annual meeting of the Central Surgical Association.
Dr. Robert Cannon
He reported on 35 patients who underwent laparoscopic resection and 138 patients undergoing open resection during the same time period. To minimize selection bias, the two groups were matched on the basis of age, size and number of lesions, whether major hepatectomy (three or more segments) or synchronous colectomy was performed, and the Fong score.
The laparoscopic group had significantly less mean blood loss than did the open group (202 mL vs. 392 mL; P less than .001), fewer complications (23% vs. 48%; P = .007), and shorter length of stay (4.8 days vs. 7.8 days; P less than .001), said Dr. Cannon of the department of surgery as the University of Louisville (Ky.).
The ability to achieve microscopically negative margins was significantly higher in the laparoscopic group, at 97%, compared with 81% in the open group (P = .02). Mortality at 90 days was similar at 0% vs. 0.7%, respectively (P = 1.0).
At 1, 3, and 5 years, median disease-free survival rates were similar at 79.3%, 37% , and 15.4%, respectively, in the laparoscopic group vs. 78.4%, 35.4% and 21.6%, respectively, in the open group (P = .715). Likewise, median overall survival rates were similar at 97%, 62.6%, and 36% vs. 95.4%, 60.3%, and 36.6% (P = .911), he said.
Dr. Cannon pointed out that the benefits of laparoscopy were observed in "appropriately selected patients," and suggested that the procedure is ideal for patients with left lateral lesions and for those who are obese.
"A thick abdominal wall doesn’t really hurt you as much when you’re going through a scope as it does when you have to make an incision that goes through all that subcutaneous fat," he said. "Also, with the shorter hospitalization, we think [laparoscopy] minimizes recovery and duration of chemotherapy in selected patients."
The higher positive-margin rate in the open group suggests that some selection bias remains in the analysis, and supports the idea that some patients – notably those with portal vein embolization, extensive disease, or tumors close to major vessels – will always be candidates for open surgery, said invited discussant Dr. Sharon Weber, professor and vice chair of general surgery at the University of Wisconsin, Madison.
Dr. Weber asked whether it’s truly possible to compare the open and laparoscopic groups statistically, or whether one can only say that outcomes tend to be better for those patients who are candidates for laparoscopic resection.
"I agree that the two groups will probably never be strictly comparable," Dr. Cannon replied. "There’s always going to be a role for open operations, especially for the lesions you mentioned [and] for those who may require biliary reconstruction or resection, or [who] have centrally located tumors such as at the base of segment four and five." He added that the purpose of doing matched studies like this one is to show that, for a patient who could go either way, perhaps the laparoscopic procedure offers benefits.
Dr. Weber also questioned how the investigators chose the factors that went into their propensity scoring, observing that some would consider factors such as neoadjuvant therapy, bilateral disease, and underlying liver fibrosis and cirrhosis equally relevant. In addition, recent work from the Netherlands suggests that the clinical risk score has become less relevant for patients with colorectal-level metastases in the era of contemporary neoadjuvant chemotherapy (Ann. Surg. Oncol. 2011;18:2757-63).
Dr. Cannon said that the availability of data influenced what factors were selected, to a large extent. The two groups had a median of one tumor, a median Charlson Comorbidity Index score of 4, and a median Fong score of 2. Their average age was 62 years. The mean tumor sizes were 4.3 cm in the open group and 4.2 cm in the laparoscopic group; positive nodes were present in 64% and 57%, respectively, and mean carcinoembryonic antigen levels at hepatectomy were 91.6 and 52, respectively.
Left lateral segmentectomy was performed in 28.6% of the laparoscopic group and in 6.5% of the open group (P less than .001), whereas wedge/bisegmentectomy was significantly more common in the open group at 34.8% vs. 14.3% in the laparoscopic group (P = .019). Rates of major hepatectomy were similar at 55.8% in the open group and 54.3% in the laparoscopic group (P = .872).