Long-Term Outcomes in Laparoscopic D2 Gastrectomy for Gastric Cancer: a Large Comprehensive Study Proposing Novel Hypotheses.

BACKGROUND

The long-term outcomes of laparoscopic gastrectomy (LG) versus open gastrectomy (OG) for gastric cancer (GC) remain obscure, especially for advanced cancer and disease affecting the upper stomach and in older patients. This study aimed to comprehensively assess the long-term efficacy of LG for GC using a large prospective database.

METHODS

Totally, 1877 consecutive patients (1186 receiving LG and 691 OG) operated in 2004-2016 were analyzed, with a median follow-up of 63 months. Association of LG versus OG with disease-specific survival (DSS) and disease-free survival (DFS) overall and in various subgroups were investigated using multivariable Cox regression. Propensity score matching (PSM) was performed for sensitivity analysis.

RESULTS

Before PSM, overall, there was no significant association of LG versus OG with survival after multivariable adjustment; however, in subgroup analyses, LG was associated with superior DSS in patients aged ≥ 70 years and those with upper GC. No significant associations regarding DFS were observed overall or in stratifications. PSM analyses revealed that LG was associated with better DSS also in patients aged ≥ 70 years (hazard ratio (HR) = 0.33, 95% confidence interval (CI) = 0.15-0.72) and in those with upper GC (HR = 0.51, 95% CI = 0.29-0.91), and with better DFS in those with upper GC (HR = 0.60, 95% CI = 0.37-0.99). Multivariable analysis showed that age, hepatitis B, performance status, tumor histology, stage, and vascular invasion were significantly associated with post-LG survival. LG-specific nomograms were then constructed with concordance indexes of 0.814 (DSS) and 0.809 (DFS) and excellent calibration.

CONCLUSIONS

In this large institutional analysis, while LG for GC was associated with DSS and DFS similar to those for OG overall, non-inferior LG-associated survival especially DSS was observed in some subgroups rarely investigated in prospective or randomized settings. There could still be biases even after PSM due to confounders not accounted for in this observational study. However, these findings offer novel hypotheses for further validation.