REGISTRATION OF COLORECTAL-CANCER IN SCOTLAND - AN ASSESSMENT OF DATAACCURACY BASED ON REVIEW OF MEDICAL RECORDS

Colorectal cancer accounts for a substantial burden of morbidity and m ortality in the population. While the need for reliable incidence data may be self-evident, the quality of cancer registration data has rare ly been assessed. In Scotland during 1993, the medical records of a ra ndom sample of cancer registrations attributed to the year 1990 were s ought. The sample contained 238 registrations of colorectal cancer, 21 7 (91%) of which had relevant medical records available for review. Re gistration details were reabstracted from available records and compar ed with data in the registry. Discrepancies in identifying items of da ta (surname, forename, sex and date of birth) were recorded in eight c ases (3.7%, 95% confidence intervals 1.2-6.2%). None would have distur bed record linkage. Discrepancy rates of 3.7% (1.2-6.3%) in postcode o f residence at the time of diagnosis (excluding differences arising th rough boundary changes), 8.3% (4.6-12.0%) in 'anniversary date' (exclu ding differences of 30 days or less), 2.8% (0.6-5.0%) in histological verification status and 13.5% (8.9-18.1%) in morphology code (excludin g 'inferred' morphology codes) were recorded. Twelve cases (5.5%, 2.5- 8.6%) were deemed not to warrant site codes for cancer of the colon (I CD-9 153) or rectum (ICD-9 154). In many respects, therefore, the data held about registrations of colorectal cancer in Scotland appear to s how a high level of accuracy. Completeness of case ascertainment has s till to be formally assessed.