Surgical resection for elderly patients is accompanied with significant perioperative mortality and frequent various postoperative complications. [4, 5] In addition, their life expectancy is limited in comparison with those of young patients, therefore indication of surgical treatment should be discussed comprehensively based on various patients’- and tumors’-related factors. In this study, 20 patients (27%) died from other diseases except for gastric cancer during follow-up period up to 5 years after gastrectomy. This is indispensable result, and OS including deaths from diseases other than gastric cancer should be considered as important as DSS in elderly patients, contrary to young patients.
Previous reports have identified gender [16, 17], surgical procedure [4, 7], PNI [7, 18] and postoperative complications [7, 17], as predictors of OS for elderGC after gastrectomy. In our study, NLR and NRC-mortality were found to be independent predictors of OS in addition to surgical procedure. Concerning surgical procedure, total gastrectomy sometimes results in malnutrition  and also cause aspiration pneumonia especially  in elderly patients. Given these insights, it may be better to avoid total gastrectomy for elderGC. Preoperative high NLR has been reported to be correlated with poor prognosis in previous reports [21–23], which are consistent with our result in this study for elderly patients. On the other hand, postoperative complication has been recognized as reliable prognostic factor after curative resection with various cancers including gastric cancers. [7, 17, 24–26] Recent our analysis demonstrated possible correlation between the adverse prognostic effect and immune status of patients, and the immune compromise of elderly patients might affect our current finding. 
NRC is originally a tool for prediction surgical morbidity and short-term surgical mortality.  The NRC-mortality is calculated based on logistic analysis from NCD big data, in which surgery-related deaths are registered from various causes including deaths due to complications, worsening of comorbidities and sudden deaths of unknown cause. We found that the NRC-mortality predicted not only the short-term mortality rate also the long-term outcomes of elderGC after gastrectomy in this study. In elderGC after gastrectomy, the perioperative mortality risk might correlate with risks of deaths due to worsening of comorbidities and sudden deaths not only perioperative-phase but also late-phase after gastrectomy, and consequently might related OS in this analysis.
POSSUM  and E-PASS  are also well-known prognostic scoring systems based on statistical analysis based on actual surgical data. Both scoring systems, however, provide the comprehensive prognostic assessment only after surgery and are not suitable for predicting an accurate surgical risk assessment prior to surgery. Moreover, the E-PASS scoring system shows that postoperative complications mainly depend on the surgical stress score, which is the actual surgical invasive outcome score.  In that sense, the NRC-mortality rate should be an ideal predictor for perioperative risk assessment, short- and long-term outcomes compared with POSSUM and E-PASS. The POSSUM scoring system is known to deviate from the risk assessment from the actual results of a limited group, such as low-risk case and the elderly patients. [30, 31] It has been reported that assessments with these scoring systems do not reflect the prognosis of elderly patients. 
There are some limitations in this study. First, this study is small-scale with a single institution. Second, this cohort included only small number of patients who underwent laparoscopic gastrectomy, which may affect long-term outcome in elderly patients due to the less invasiveness. Further multi-institutional analyses with large number of patients who underwent open and laparoscopic gastrectomy should be conducted to confirm the clinical usefulness of this predictor.
In conclusion, the NRC-mortality, as well as surgical procedure and NLR value, might be clinical useful for not only predicting surgical mortality but also OS after gastrectomy in elderGC.