Despite the importance of estimating population level cancer outcomes, most registries do not collect critical events such as relapse. Attempts to use health administrative data to identify these events have focused on older adults and have been mostly unsuccessful. We developed and tested administrative data-based algorithms in a population-based cohort of adolescents and young adults with cancer.
We identified all Ontario adolescents and young adults 15–21 years old diagnosed with leukemia, lymphoma, sarcoma, or testicular cancer between 1992–2012. Chart abstraction determined the end of initial treatment (EOIT) date and subsequent cancer-related events (progression, relapse, second cancer). Linkage to population-based administrative databases identified fee and procedure codes indicating cancer treatment or palliative care. Algorithms determining EOIT based on a time interval free of treatment-associated codes, and new cancer-related events based on billing codes, were compared with chart-abstracted data.
The cohort comprised 1404 patients. Time periods free of treatment-associated codes did not validly identify EOIT dates; using subsequent codes to identify new cancer events was thus associated with low sensitivity (56.2%). However, using administrative data codes that occurred after the EOIT date based on chart abstraction, the first cancer-related event was identified with excellent validity (sensitivity, 87.0%; specificity, 93.3%; positive predictive value, 81.5%; negative predictive value, 95.5%).
Although administrative data alone did not validly identify cancer-related events, administrative data in combination with chart collected EOIT dates was associated with excellent validity. The collection of EOIT dates by cancer registries would significantly expand the potential of administrative data linkage to assess cancer outcomes.
*Division of Haematology/Oncology, The Hospital for Sick Children
†Faculty of Medicine, University of Toronto
‡Cancer Research Program, Institute for Clinical Evaluative Sciences
§Institute for Health Policy, Evaluation and Management, University of Toronto
∥Department of General Surgery, Li Ka Shing Knowledge Institute St. Michael’s Hospital
¶Canadian Partnership Against Cancer
#Pediatric Oncology Group of Ontario, Toronto, ON, Canada
Supported by a Young Investigator Award to S.G. from Alex’s Lemonade Stand. The building of the IMPACT cohort was funded through a Project Grant from the Canadian Institutes of Health Research (CIHR—MOP 133618); a CIHR Foundation Grant (NB—FND 148470); the C17 Council; and the Pediatric Oncology Group of Ontario. This study was also supported by the Institute for Clinical Evaluative Sciences (ICES), which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). No endorsement by ICES or the Ontario MOHLTC is intended or should be inferred. Parts of this material are based on data and information compiled and provided by CIHI. However, the analyses, conclusions, opinions and statements expressed herein are those of the author, and not necessarily those of CIHI.
The authors declare no conflict of interest.
Reprints: Sumit Gupta, MD, PhD, Division of Haematology/Oncology, Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada, M5G 1X8. E-mail: firstname.lastname@example.org.