Abstract
BACKGROUND: Ovarian cancer is the most lethal gynecologic cancer. This study explores differences in observed survival rates among ovarian cancer patients treated in certified versus non-certified hospitals in Germany. METHODS: The study used data from German statutory health insurance (SHI) funds and clinical cancer registries (CCRs), including 20,794 insured and 4,493 registry patients diagnosed with a malignant ovarian neoplasm (ICD-10-GM code C56) from 2009 to 2017. Patients were categorized based on whether they received primary treatment at hospitals certified as ovarian cancer centers by the German Cancer Society (DKG) or at non-certified hospitals. Survival analyses were conducted using Kaplan-Meier and multivariable Cox regression methods. Adjustments were performed for age, year of diagnosis, International Union Against Cancer (UICC) stage, grade, lymphatic and venous invasion, year of index treatment, distant metastasis, Elixhauser comorbidities, and hospital criteria where available in the data source used. RESULTS: After adjustment for various confounders, treatment in certified centers was associated with a lower mortality risk, corresponding to a hazard ratio (HR) of 0.883 (95% CI 0.824-0.948; p = 0.001) in the SHI data. In the CCR data a non-significant HR of 0.964 was observed (95% CI 0.867-1.071; p = 0.490). Among patients in the CCR cohort diagnosed with UICC stage I-III disease, receiving treatment at certified centers was associated with improved survival outcomes (HR 0.825, 95% CI 0.708-0.961; p = 0.014). CONCLUSION: Treatment in DKG-certified centers is associated with better survival in ovarian cancer patients, especially in earlier stages. Certification status may be a relevant factor when choosing a treatment facility. TRIAL REGISTRATION: ClinicalTrials.gov (identifier: NCT04334239). Retrospectively registered on 6 April 2020.