Using cancer registry data for survival studies: the example of the Ontario Cancer Registry.
OBJECTIVE
The Ontario Cancer Registry (OCR) is a population-based tumor registry created to provide data for epidemiologic research and for cancer surveillance. Recently it has been used for health services research. The objective of this project was to assess the quality of the OCR data that is used in survival analysis.


METHODS
Clinical information for 898 patients with squamous carcinoma of the head and neck including index tumor site, date of diagnosis, vital status, date of death, and cause of death from a prospective database at the Kingston Regional Cancer Center is compared to the same data elements in the OCR for the same patients.


RESULTS
There is no statistically significant difference in disease-specific survival between the information from the two databases (log rank P = .89). The OCR captured and correctly assigned index tumor site for 81.4% (detection rate). The site assignment was accurate 90.9% of the time (confirmation rate), there was agreement on vital status (dead vs. alive) for all but one patient, and there was excellent agreement on date of death. However, cause of death (cancer vs. noncancer) based on death certificates had a 31% error rate.


CONCLUSIONS
Researchers can be confident in the survival analysis generated from data in this registry, but need to be aware of potential sources of error.
Hall
Stephen
S
Division of Cancer Care and Epidemiology, Queen's Cancer Research Institute, 10 Stuart St, Kingston Ontario K7L 3N6, Canada. sfh@post.queensu.ca
Schulze
Karleen
K
Groome
Patti
P
Mackillop
William
W
Holowaty
Eric
E
D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality*; D002423:Cause of Death; D003625:Data Collection / Q000592:standards; D006258:Head and Neck Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality*; D006801:Humans; D009361:Neoplasm Invasiveness; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality; D009864:Ontario; D012042:Registries / Q000592:standards; D016019:Survival Analysis