Modified Charlson comorbidity index of long-term, non-gastric cancer mortality in patients with early gastric cancer: a multicenter retrospective study.

Purpose: In patients with early gastric cancer (EGC) who undergo endoscopic submucosal dissection (ESD) with endoscopic curability (eCura) C-2, the risk of non-gastric cancer mortality should be evaluated before receiving further gastrectomy. Charlson comorbidity index (CCI) is often used to estimate prognosis based on patient's background before treatment. We identified the long-term risk of mortality from other causes associated with comorbidities in CCI and applied it to the creation of EGC specific CCI (GCCI).

Methods: A total of 1810 patients with EGC from 3 centers were included from January 2015 to February 2023. We used Cox proportional risk models to determine the risk of non-gastric cancer mortality related to comorbidities and used these hazard ratios to reweight the Charlson index to establish GCCI.

Results: The Cox model suggested that moderate to severe liver disease, metastatic solid tumors, severe to very severe chronic obstructive pulmonary disease (COPD), and leukemia had the highest risk of non-gastric cancer mortality [hazard ratio (HR) > 5)]. Survival analysis showed that the 5-year non-gastric cancer mortality rates in low-risk group (GCCI score 0-1), medium-risk group (GCCI score 2-4), and high-risk group (GCCI score 5-13) were 3%, 10%, and 52%, respectively.

Conclusions: GCCI could identify patients with EGC who have higher non-gastric cancer mortality. The GCCI could be used to help patients with EGC make medical decisions.