Laparoscopic Compared to Open Gastrectomy

Gastric cancer is the fourth most common cancer worldwide, and the second highest global cause of cancer mortality, affecting more than 870,000 individuals annually.¹ Risk factors for gastric cancer include interactions between diet and lifestyle²: esophageal reflux, socioeconomic and environmental challenges, advanced age, male gender, short stature,³ and gastric microbial burden of Helicobacter pylori.⁴ Gastrectomy is often required to remove the cancer and affected lymph nodes. Laparascopically assisted gastrectomy, introduced in 1994,⁵ has growing research to inform clinical decisions about its effectiveness and safety. This month’s Evidence Corner explores 2 of several recent meta-analyses comparing clinical outcomes of less invasive laparascopic gastrectomy (LG) variations to those of conventional open gastrectomy (OG) in management of gastric cancer. The first compares long-term outcomes of LG to those achieved with OG.⁶ The second compares outcomes of robotic laparoscopic gastrectomy (RG) to OG.⁷

Laura Bolton, PhD Adjunct Associate Professor Department of Surgery Rutgers Robert Wood Johnson University Medical School New Brunswick, NJ

  Reference: Choi YY, Bae JM, An JY, Hyung WJ, Noh SH. Laparoscopic gastrectomy for advanced gastric cancer: Are the long-term results comparable with conventional open gastrectomy? A systematic review and meta-analysis. J Surg Oncol. 2013;108(8):550-556.   

Rationale: Randomized controlled trials report less pain and recovery time and better quality of life with comparable morbidity and mortality using laparascopic gastrectomy (LG) compared to open gastrectomy (OG) in managing gastric cancer. For individuals with advanced gastric cancer, limited research has compared long-term LG to OG oncologic outcomes, such as overall survival (OS) or disease-free survival (DFS).   

Objective: Conduct a systematic review and meta-analysis to compare long-term oncologic results of performing LG or OG on patients with advanced gastric cancer.   

Methods: A quantitative systematic review meta-analyzed results of randomized or nonrandomized controlled trials (RCTs or NRCTs) or cohort studies found in searches of the EMBASE and MEDLINE databases and the Cochrane Central Register. Studies were included relating to LG (including laparoscopically assisted gastrectomy) compared to conventional OG only if they reported OS and/or DFS outcomes for subjects during a follow-up period of 36 months or longer after hospitalization for LG or OG for advanced gastric cancer. Methods met standardized criteria for systematic reviews and meta-analyses outlined in the PRISMA statement.⁸ Risk of bias was assessed using the Newcastle-Ottawa scale for each cohort study and the Jadad scale for a RCT. Hazard ratios for OS and for DFS were calculated from time-to-event analyses and estimated from Kaplan-Meier curves, where available, using plot digitizing software. Heterogeneity of effect sizes across the included studies was analyzed using the Cochran Q and Higgins I2 statistics.   

Results: Of 294 records located, 10 qualified for meta-analysis: 9 cohort studies (913 OG subjects; 810 LG subjects) and 1 RCT (47 OG subjects; 49 LG subjects). Neither OS (9 studies) nor DFS (5 studies) differed significantly between subjects who underwent OG or LG. Both results were sustained during subgroup analyses of studies with higher or lower risk of bias. There were similar numbers of lymph node dissections in the 2 treatment groups and no evidence of significant bias or heterogeneity among studies, which were mainly from areas with endemic gastric cancer, where it was likely the surgeons had considerable experience with both types of procedures.   

Authors’ Conclusions: Current clinical evidence suggests that oncologic outcomes of OG and LG may be similar, pending findings of ongoing clinical RCTs.

  Reference: Liao G, Chen J, Ren C, et al. Robotic versus open gastrectomy for gastric cancer: A meta-analysis. PLoS ONE. 2013;8(12):e81946.   

Rationale: Robotic surgery improves visibility and manipulation in LG and associated lymph node dissection in patients with gastric cancer. However, robotic laparoscopic gastrectomy (RG) has not been compared with OG to establish its relative safety and efficacy.   

Objective: A systematic review and meta-analysis compared safety and efficacy of RG to that of OG in treating patients with gastric cancer.   

Methods: Two authors searched the Cochrane Library, PubMed, EMBASE, and Web of Knowledge databases up to July 3, 2013 for articles including the following terms: robotic surgery, da Vinci, gastric cancer, and gastrectomy. Uncontrolled or irrelevant studies were excluded. Two independent reviewers extracted, summarized, and analyzed operative time, blood loss, overall postoperative complication rate (including separate analyses of wound infection rate, anastomotic leakage, and bleeding), postoperative hospital stays, numbers of harvested lymph nodes, and postoperative and mortality outcomes of all qualifying studies. Study quality was assessed using the Newcastle-Ottawa scale. Review manager software was used to conduct the meta-analysis, using weighted mean differences for continuous variables and odds ratios for dichotomous variables. Heterogeneity was tested using a chi square statistic, I². A fixed-effects analytic model was applied if I² < 50% and a random effects model was applied if I² > 50%.   

Results: Among 365 abstracts reviewed, 4 retrospective case studies on 520 RG and 5,260 OG patients in China, Italy, and Korea qualified for analysis. Postoperative hospital stay and intra-operative blood loss were both heterogeneous across studies and significantly less for RG than for OG (P < 0.0001). Operation time was heterogeneous across studies and longer for RG than for OG (P < 0.00001). No significant differences were reported for any other outcome analyzed. There was no significant evidence of publication bias.   

Authors Conclusions: Compared to conventional OG, RG is a safe, efficient procedure that increases operation time, but reduces blood loss and length of hospital stay. On most other gastrectomy outcomes associated with gastric cancer, RG is comparable to OG and may be a more practical, feasible technique than OG. Prospective RCTs are needed to confirm this.

  Systematic reviews and meta-analyses are recognized as the most powerful evidence informing clinical decisions, but it is wise to take a closer look at the quality of the data included in each one before assuming sterling evidence quality of a meta-analysis. Choi et al⁶ reported a Jadad score of 2 for the only RCT included in their analysis. While Jadad scores can range from 1 to 5, scores below 3 may be of questionable quality.⁹ As the authors conclude, more and better quality RCTs are recommended to strengthen conclusions of LG comparative safety or efficacy in managing gastric cancer. Quality of the cohort studies was better at 7 to 8 stars out of a possible 9 on the Newcastle-Ottawa scale; however, no cohort study in the Choi et al meta-analysis controlled for factors beyond age, gender, and marital status. Cohort data matched on disease stage and/or surgical site would be more compelling. Despite these limitations, the data clearly support conduct of the well-designed KLASS-02 RCT comparing LG to OG now being conducted in Korea.¹⁰ The RG vs OG meta-analysis would be strengthened by including RCTs, but none were found.⁷ Both studies reviewed here may be used with caution to inform clinical decisions until stronger RCT evidence is available. Any surgical option that reduces blood loss and hospital stay without compromising short-term or long-term clinical or oncologic outcomes merits the development of quality evidence in its support.