A good preoperative immune prognostic index is predictive of better long-term outcomes after laparoscopic gastrectomy compared with open gastrectomy for stage II gastric cancer in elderly patients.

Background: It remains inconclusive whether laparoscopic gastrectomy (LG) has better long-term outcomes when compared with open gastrectomy (OG) for elderly gastric cancer (EGC). We attempted to explore the influence of the immune prognostic index (IPI) on the prognosis of EGCs treated by LG or OG to identify a population among EGC who may benefit from LG.

Methods: We included 1539 EGCs treated with radical gastrectomy from January 2007 to December 2016. Propensity score matching was applied at a ratio of 1:1 to compare the LG and OG groups. The IPI based on dNLR ≥ cut-off value (dNLR) and sLDH ≥ cut-off value (sLDH) was developed, characterizing two groups (IPI = 0, good, 0 factors; IPI = 1, poor, 1 or 2 factors).

Results: Of the 528 EGCs (LG: 264 and OG: 264), 271 were in the IPI = 0 group, and 257 were in the IPI = 1 group. In the entire cohort, the IPI = 0 group was associated with good 5-year overall survival (OS) (p = 0.001) and progression-free survival (PFS) (p = 0.003) compared to the IPI = 1 group; no significant differences in 5-year OS and PFS between the LG and OG groups were observed. In the IPI = 1 cohort, there was no significant difference in OS or PFS between the LG and OG groups across all tumor stages. However, in the IPI = 0 cohort, LG was associated with longer OS (p = 0.015) and PFS (p = 0.018) than OG in stage II EGC, but not in stage I or III EGC. Multivariate analysis showed that IPI = 0 was an independent protective factor for stage II EGC receiving LG, but not for those receiving OG.

Conclusion: The IPI is related to the long-term prognosis of EGC. Compared with OG, LG may improve the 5-year survival rate of stage II EGC with a good IPI score. This hypothesis needs to be further confirmed by prospective studies.