Background: Ovarian cancer (OC) requires complex multidisciplinary care with wide variations in outcome. We sought to determine the impact of institutional and process of care factors on overall survival (OS) and delivery of guideline care nationally.
Methods: This was a retrospective cohort study of primary OC diagnosed from 1998 to 2007 using the National Cancer Data Base (NCDB) capturing 80% of all U.S. cases. Patient- (demographics, comorbidities, stage/grade), process of care (adherence to guidelines) and institutional- (facility type, case volume) factors were evaluated. Primary outcomes were OS and delivery of guideline therapy. Multivariable logistic regression and Cox proportional hazards models were used for analysis.
Results: We analyzed 96,802 consecutive cases. Five-year OS was 84%, 66.3%, 32% and 15.7% for stages I, II, III and IV, respectively. The annual mean facility case volumes varied by cancer center type (range: 5.7 to 26.7), with 25% of cases spread over 65% of centers--all treating fewer than 8 cases. Overall, 56% of cases received non-guideline care. Low facility case volume and higher comorbidity index independently predicted non-guideline care; high volume centers were less likely to deliver non-guideline care (OR: 0.44, 95% CI: 0.41-0.47). Delivery of non-guideline care (OR: 1.4, 95% CI: 1.36-1.44), and higher facility case volume (OR: 0.91, 95% CI: 0.86-0.96) were both independent predictors of OS.
Conclusions: Delivery of guideline care and facility case volume are important drivers of overall survival. Most cancer centers treat very few women with OC. National efforts should focus on improved access to centers with expertise in OC and ensuring delivery of guideline care.
Keywords: Cancer center; Care patterns; Ovarian cancer; Survival; United States; Volume.
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