Temporal trends in short-term mortality in more than 5000 patients with early-stage ovarian cancer in Denmark and Sweden.

OBJECTIVES: To describe trends in and levels of short-term mortality risk of early-stage epithelial ovarian cancer (EOC) in Denmark and Sweden, overall and by age at diagnosis, stage, histology, and socioeconomic status (SES). METHODS: From the Danish (2004-2019) and Swedish (2004-2022) Cancer Registry, we included all patients registered with early-stage EOC, defined by the International Federation of Gynecology and Obstetrics (FIGO) as stages I + II. Information about SES, measured by educational level, income, and marital status, was retrieved from nationwide registries. We calculated short-term (3-month, 6-month, and 1-year) absolute all-cause mortality risks by calendar period using the Kaplan Meier method. The 1-year mortality risks were additionally stratified by age at diagnosis, stage, histology, and SES. RESULTS: The 1-year absolute mortality risk among Danish patients decreased by 6% per year (95% CI: -12 to 0%) in the study period, whereas it was stable in Sweden. The decreasing mortality risk in Denmark was seen for all levels of SES but tended to be more pronounced in patients with low SES and older patients. Time trends in mortality risk in Sweden did not seem to vary substantially across patient groups except for a decline in patients with mucinous tumors and an increase among those with other epithelial tumors. CONCLUSIONS: Since 2004, 1-year absolute mortality risk of early-stage EOC decreased in Denmark (low SES and older patients) and remained stable in Sweden, resulting in comparable levels in recent years, probably explained by improved diagnostics, surgery centralization, and implementation of standardized cancer patient pathways.