RT Journal Article SR Electronic T1 Cohort profile: the Dutch oral cavity cancer cohort JF BMJ Open JO BMJ Open FD British Medical Journal Publishing Group SP e092467 DO 10.1136/bmjopen-2024-092467 VO 15 IS 5 A1 van Oorschot, Hanneke Doremiek A1 Hardillo, Jose Angelito A1 Baatenburg de Jong, Robert Jan A1 YR 2025 UL http://bmjopen.bmj.com/content/15/5/e092467.abstract AB 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.Data are available upon reasonable request. The authors welcome and encourage research collaborations using the DHNA-OC cohort, and researchers interested in collaborating on the cohort are welcome to contact the research group. Data requests will be handled by PRISMA, the scientific advisory committee for research in head and neck cancer in the Netherlands (https://iknl.nl/kankersoorten/hoofd-halskanker/onderzoek/prisma )