In an individual patient-level meta-analysis reported in the Annals of Surgery, Syn et al found that laparoscopic resection vs open surgery was associated with significantly improved overall survival as treatment for colorectal liver metastases.
“This patient-level meta-analysis of high-quality studies demonstrated an unexpected survival benefit in favor of laparoscopic over open resection for [colorectal liver metastases] in the long-term. From a conservative viewpoint, these results can be interpreted to indicate that laparoscopy is at least not inferior to the standard open approach.”— Syn et al
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The meta-analysis included data from 3,148 patients from 2 randomized trials and 13 propensity score-matching studies. Survival data for the individual patients were reconstructed from reported Kaplan-Meier curves. Frequentist and Bayesian survival models incorporating random-effects and nonproportional hazards were fitted to permit overall survival comparison between laparoscopic resection and open surgery. To address long plateaus in survival curve tails, “cure models” were used to estimate proportions of patients who could be categorized as “cured” of disease.
The primary analysis for overall survival was based on Cox regression analysis stratified for study subgroups.
Laparoscopic resection was associated with a significantly reduced risk of all-cause mortality (stratified hazard ratio [HR] = 0.853, 95% confidence interval = 0.754–0.965, P = .0114).
Evidence of time-varying effects was observed (P = .0324), with survival curves beginning to significantly diverge at 26.5 months and magnitude of HRs favoring laparoscopic resection increasing over time.
Restricted mean survival times were 8.6 months longer at 10 years (P < .0001) and 30.0 months longer at 15 years (P < .0001) in the laparoscopy group, corresponding to relative life expectancy gains of 12.1% and 38.6%, respectively.
Kaplan-Meier plots for both groups appeared to plateau at 108.0 months, with the estimated fraction of long-term survivors (“cures”) being 47.4% in the laparoscopic resection group vs 18.0% in the open surgery group.
A subgroup analysis indicated that laparoscopy was associated with significantly better 3-year survival among patients aged ≥ 65 years (P = .018), with 46.1% remaining alive at 5 years.
The investigators concluded, “This patient-level meta-analysis of high-quality studies demonstrated an unexpected survival benefit in favor of laparoscopic over open resection for [colorectal liver metastases] in the long-term. From a conservative viewpoint, these results can be interpreted to indicate that laparoscopy is at least not inferior to the standard open approach.”
Nicholas L. Syn and Brian K. P. Goh, MMed, MSc, of the Department of Hepatopancreatobiliary and Transplant Surgery, Singapore General Hospital, are the corresponding authors for the Annals of Surgery article.
Disclosure: For full disclosures of the study authors, visit journals.lww.com.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.