BACKGROUND: Long-term data on the prognosis of patients who survive >
5 years following gastrectomy for gastric cancer (GC) remain scarce. This study aimed to investigate sequential changes in conditional survival (CS) in these patients. METHODS: Of 1,129 patients with stage I-III GC who underwent R0 gastrectomy, the causes of death were assessed, and sequential changes in conditional overall survival (cOS), disease-specific survival (cDSS), and 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 clinicopathological factors were analyzed. RESULTS: Over a median follow-up of 63 months, 203 (18.0%) patients died from GC, and 131 (11.6%) died from non-GC causes. The 5-year cDSS consistently increased over the 10 years following gastrectomy in stages II and III. For stage II, cDSS and cNDSS intersected at 7 years post-gastrectomy, whereas for stage III, these measures crossed at 8 years. In the 709 5-year survivors, multivariate analysis identified disease stage as significantly associated with cOS and cDSS. Moreover, age ≥75, male sex, and preoperative comorbidities were associated with lower cNDSS. CONCLUSION: Surveillance for GC relapse was critical during the first 7 and 8 years post-gastrectomy for stages II and III, respectively. Conversely, surveillance for second primary cancers and benign diseases became relatively more important after 0, 7, and 8 years post-gastrectomy for stages I, II, and III, respectively. In 5-year survivors, age ≥75, male sex, and preoperative comorbidities were associated with mortality unrelated to GC.