Prognosis after surgery for gastric adenocarcinoma in the Swedish Gastric Cancer Surgery Study (SWEGASS)

Abstract

BACKGROUND: Most studies examining prognostic factors after gastrectomy come from selected patients and non-Western populations. This nationwide population-based cohort study aims to identify prognostic factors after surgery for gastric adenocarcinoma in an unselected Western cohort. METHODS: This study included 98% of patients who underwent gastrectomy for gastric adenocarcinoma in Sweden in 2006-2015, with follow-up through 2019. Data were collected from medical records and national registries. Exposures were sex, age, education, comorbidity, tumor sub-localization, tumor stage, calendar period, and pre-operative chemotherapy. Outcomes were 3-year all-cause and disease-specific mortality. Cox regression produced hazard ratios (HRs) with 95% confidence intervals (95% CIs), adjusted for the other study exposures. RESULTS: Among all 2154 patients, 3-year all-cause mortality was 53.3%. Factors influencing 3-year all-cause mortality after multivariable adjustment were tumor stage (stage IV vs. stage 0-I: HR 8.72, 95% CI 6.77-11.24), comorbidity (Charlson comorbidity score ≥2 vs. 0: HR 1.63, 95% CI 1.39-1.90), age (>75 vs. <65 years: HR 1.48, 95% CI 1.24-1.78), and calendar period (2006-2010 vs. 2011-2015: HR 0.83, 95% CI 0.73-0.95). No independent prognostic influence was found for sex (women vs. men: HR 1.01, 95% CI 0.85-1.09), pre-operative chemotherapy (yes vs. no: HR 0.92, 95% CI 0.78-1.08), tumor sub-localization (non-cardia vs. cardia: HR 1.01, 95% CI 0.83-1.22), or education (≥13 vs. ≤9 years: HR 0.89, 95% CI 0.74-1.07). The results were similar for 3-year disease-specific mortality. CONCLUSION: Survival after gastrectomy for gastric adenocarcinoma needs further improvement. Tumor stage, comorbidity, age, and calendar period were independently prognostic, while sex, pre-operative chemotherapy, tumor sub-localization, and education were not.

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