Cohort profile: the Dutch oral cavity cancer cohort

Purpose The Dutch Head and Neck Audit-Oral Cavity (DHNA-OC) cohort was collected to study the quality of care, current treatment and survival for oral cavity cancer (OCC) across all hospitals treating head and neck cancer (HNC) in the Netherlands. Patients The DHNA-OC is a registry-based national cohort of 2545 first primary OCC patients treated with curative intent between 2018 and 2021. All 14 HNC hospitals in the Netherlands contributed, guaranteeing national coverage. The DHNA-OC cohort is an elaborate dataset including variables on patient and tumour characteristics, treatment, complications, recurrence rates and survival. Findings to date The median age at diagnosis was 67 years and most tumours were early stage (cT1 in 32% and cT2 in 31%). Tongue tumours were most common, and surgery was performed in 91.3% of the patients. The number of included patients per hospital varied from 82 to 367. The proportion of advanced tumour stage varied significantly between hospitals. Substantial data completeness was acquired with only two variables exceeding 10% missing (comorbidities and performance score). Future plans The DHNA-OC cohort will be used to study benchmarking of and current knowledge gaps in OCC care. Collaboration with other institutions or national/regional databases is highly encouraged. Some examples of planned studies are the assessment of hospital variation in outcome indicators for surgery and population-based treatment effects. The results of these studies will be used to identify best practices and continue improving the quality of care. Longitudinal cohort follow-up and enrolment will continue prospectively.