BACKGROUND: Long-term data on the prognosis of patients who survived >
5 years after gastrectomy for gastric cancer (GC) remain scarce. This study aimed to investigate sequential changes in conditional survival (CS) in patients with stage I-III GC who underwent R0 gastrectomy. METHODS: Of 1129 patients with stage I to III GC who underwent R0 gastrectomy, the causes of death were assessed, and sequential changes in conditional overall survival (cOS), conditional disease-specific survival (cDSS), and conditional non-disease-specific survival (cNDSS) were calculated and compared. In a subgroup of 709 patients who survived >
5 years, the associations between cOS, cDSS, cNDSS, and clinicopathologic factors were analyzed. RESULTS: Over a median follow-up of 63 months, 203 patients (18.0%) died of GC, and 132 patients (11.7%) died of non-GC causes. The 5-year cDSS consistently increased over 10 years after gastrectomy for stage II and III GC. The cDSS and cNDSS intersected at 7 years after gastrectomy for stage II GC, whereas these measures crossed at 8 years after gastrectomy for stage III GC. In the 709 5-year survivors, multivariate analysis identified disease stage as being significantly associated with cOS and cDSS. Moreover, age ≥ 75 years, male sex, and preoperative comorbidities were associated with lower cNDSS. CONCLUSION: Surveillance for GC relapse was crucial during the first 7 and 8 years after gastrectomy for stages II and III, respectively. Conversely, surveillance for second primary cancers and benign diseases became relatively more important 0, 7, and 8 years after gastrectomy for stages I, II, and III, respectively. In 5-year survivors, age ≥ 75 years, male sex, and preoperative comorbidities were associated with mortality unrelated to GC.