Background and objectives: Conditional survival (CS) provides the probability that a patient who has already survived a certain number of years after treatment will survive an additional number of years. We aim to study the CS of patients with gastric cancer.
Methods: Patients who underwent curative intent treatment for gastric cancer in a single institution between 2007 and 2018 were included in the analysis. The probability (CS) that a patient who has already survived x years will survive an additional y year, was calculated as CS (y/x) = S(x + y)/S(x).
Results: The probability of surviving an additional 3 years if a patient had already survived 1, 2, 3, 4, and 5 years after treatment were 64.2%, 74.5%, 81.6%, 83.2%, and 88.2%, respectively whereas the 4-, 5-, 6-, 7-, and 8-year actuarial OS were only 47.2%, 43.2%, 41%, 39.4%, and 38.2%, respectively. The independent prognostic factors associated with poor survival were age >60 years, T stage ≥T3, N stage ≥N2, proximal tumor location, and lymph node ratio > 0.18. Patients with these high-risk features showed the greatest increase in CS3 over time.
Conclusion: CS estimates provided a more dynamic prognostic information over time for patients treated for gastric cancer with curative intent.
Keywords: conditional survival; gastric cancer; lymph node ratio; surgery; survival.
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