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Identification of patients with incident cancers using administrative registry data

Mette Bach Larsen1, 2, Henry Jensen1, 2, Rikke Pilegaard Hansen1, 2, Frede Olesen1 & Peter Vedsted1, 2

3. feb. 2014
2 min.


On-time identification of incident cancer patients is important in cancer research to ensure quality in cancer treatment and care. Nevertheless, the Danish Cancer Registry (DCR) is updated on an annual basis rather than continuously, and no standardised algorithm exists to enable sampling from administrative data which are updated on a monthly basis. The aim of this study was to develop and validate an algorithm for on-time sampling of incident cancer patients based on administrative data.


The study was based on registry and questionnaire data from incident cancer patients’ general practitioners (GPs). An algorithm for on-time sampling of incident cancer patients was developed and validated in 2008 (12,747 patients) and further developed and validated in 2010 (7,996 patients). Questionnaire data from the GPs and data from the DCR were used as golden standards. The completeness over time of the 2010 cohort was evaluated.


Further development of the 2008 algorithm into the 2010 algorithm increased its positive predictive value (PPV) to 95.0%. The PPV of a patient from the 2010 cohort being registered in the DCR was 97.4%. The 2010 algorithm displayed a completeness of 60% in the first month and 95% after four months.


Avalid and cost-saving algorithm for on-time sampling of incident cancer patients has been developed with great potential for research and quality assurance.


This work was funded by the Danish Cancer Society and the Novo Nordisk Foundation.


Not relevant.

CORRESPONDENCE: Mette Bach Larsen. E-mail:

CONFLICTS OF INTEREST: Disclosure forms provided by the authors are available with the full text of this article at

Reference: Dan Med J 2014;61(2):A4777