Comorbidity is an independent prognostic factor for the survival of ovarian cancer: A Danish register-based cohort study from a clinical database

Abstract Objective The aim of the study was to examine whether comorbidity is an independent prognostic factor for 3129 women diagnosed with ovarian cancer from 2005 to 2011. As Performance status (PS) might capture the impact of comorbidity we addressed whether comorbidity can be explained by PS or whether comorbidity has an independent impact on survival. Methods The Danish Gynecological Cancer Database (DGCD) is a national clinical database including information on comorbidity and a large number of tumor-related and patient-related factors. The Charlson Comorbidity Index was used to measure the patients' comorbidity based on the registration in DGCD. The overall mortality (OS) from the date of surgery to death or censoring was the outcome measure. Results The hazard ratio (HR) for patients with comorbidity was 3.31 (1.14–1.50) compared to patients without comorbidity after adjustment for age, stage, residual tumor, histology and grade. After including PS in the model, comorbidity remained significant for OS. Age, stage, residual tumor, histology and PS prove to be independent prognostic factors as well. No association is found between comorbidity and receiving surgery or not. Conclusion Comorbidity is an independent prognostic factor, and has a negative impact on the survival of ovarian cancer patients. However, comorbidity has a smaller impact on survival compared with the other prognostic factors considered.