by Mike Bassett, Staff Writer, MedPage Today July 20, 2022

Five-year follow-up results from the KLASS-02 randomized trial confirmed that laparoscopic surgery is not inferior to open gastrectomy in patients with locally advanced gastric cancer.

At a median follow-up of 69.4 months, 5-year relapse-free survival (RFS) rates were comparable in patients who underwent laparoscopic or open gastrectomy (79.5% vs 81.1%, P=0.69), reported Sang-Uk Han, MD, PhD, of Ajou University School of Medicine in Suwon, South Korea, and colleagues.

These rates, published in JAMA Surgery, were similar to the 3-year RFS rates (the study's primary outcome) reported in the trial's initial analysis (80.3% vs 81.3%, respectively).

At the same time, the 5-year overall survival (OS) rate did not differ significantly between patients who underwent laparoscopy and those who underwent open gastrectomy (88.9% vs 88.7%, P=0.30). Three-year OS rates for the laparoscopy and open surgery groups were 90.6% and 90.3%, respectively.

Furthermore, the late complication rate was significantly lower in the laparoscopic group than in the open group, and is "one of the advantages of laparoscopic surgery," Han and co-authors said.

In their original analysis the researchers reported that patients in the laparoscopy group not only had fewer complications than patients in the open surgery group (15.7% vs 23.4%), but also had significantly fewer late complications (4.7% vs 9.5%). This finding was confirmed in this latest analysis (6.5% of patients in the laparoscopy group vs 11.0% in the open surgery group).

Intestinal obstruction was the most common surgical complication (43.5%), with rates of intestinal obstruction (2.6% vs 5.0%) and chronic wound complications (0.6% vs 1.9%) lower in the laparoscopy group than in the open group. Major complications were more frequent in the open group, although the difference was not statistically significant, the team said.

In a commentary accompanying the study, Vivian E. Strong, MD, of Memorial Sloan Kettering Cancer Center in New York City, and colleagues wrote that while the researchers should be commended for carrying out a large, well-conducted study, several factors should be taken into account when applying the results to Western populations.

For example, Strong and co-authors said, Western patients have a higher incidence of both proximal tumors and diffuse-type histology, and are more likely to require total gastrectomy. Considering that the Dutch STOMACH trial found no difference in morbidity between laparoscopic and open total gastrectomy, the KLASS-02 findings cannot be extrapolated to total gastrectomy, the commentators said.

Furthermore, they noted, while neoadjuvant plus adjuvant chemotherapy is standard for locally advanced gastric cancer in Western countries, no patients in KLASS-02 received neoadjuvant chemotherapy since adjuvant chemotherapy alone is the standard in East Asian countries.

"Nevertheless, the results of KLASS-02 have exciting implications," said Strong and co-authors. "Ultimately, the goal is to provide patients with a safe high-quality cancer operation, regardless of approach. The long-term results of KLASS-02 confirm that minimally invasive surgery for gastric cancer may offer exactly that, with the added benefit of decreased morbidity, if done in expert hands with thoughtful patient selection."

The phase III, open-label randomized controlled trial was conducted by 20 surgeons from 13 tertiary hospitals in South Korea. Included were 1,050 patients, ages 20 to 80, who had an ECOG performance status score of 0 or 1, primary gastric carcinoma with clinical stage T2-4a, and no nodal metastasis or only limited perigastric nodal metastasis in the preoperative studies.

Five-year outcomes were analyzed in 492 patients in the laparoscopic group (mean age 59.8 years, 71.3% male) and 482 in the open group (mean age 59.4, 69.5% male).

In the 5-year analysis the number of deaths or recurrences was 108 (21.9%) in the laparoscopy group and 101 (20.9%) in the open group. A total of 58 patients (11.8%) in the laparoscopy group and 69 patients (14.3%) in the open group died during the follow-up period, and 93 (18.9%) and 80 (16.6%), respectively, had recurrences.

The most common type of recurrence was peritoneal carcinomatosis (42.1% of patients), followed by hematogenous metastases (20.8%), locoregional recurrence (13.2%), and distal lymph node metastases (9.8%). More than 80% of all recurrences were recorded within the first three postoperative years, the researchers said.

Mike Bassett is a staff writer focusing on oncology and hematology. He is based in Massachusetts.

The study was supported in part by grants to Han from the National R&D Program for Cancer Control from the Ministry of Health and Welfare, Republic of Korea, and Ethicon Endo-Surgery, a Johnson & Johnson Company.

Co-authors reported financial relationships with Medtronic, GC Pharma, Hutom, SK Hynix, Daewoong Pharmaceuticals, JW Pharmaceuticals, DN Company Co., and Ethicon.

Strong and co-authors reported no conflicts of interest.

Source Reference: Son S-Y, et al "Laparoscopic vs open distal gastrectomy for locally advanced gastric cancer" JAMA Surg 2022; DOI: 10.1001/jamasurg.2022.2749.

Source Reference: Li G, et al "Bigger may not be better -- Implications of long-term results from KLASS-02" JAMA Surg 2022; DOI: 10.1001/jamasurg.2022.2773.

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