Approaches to quality control with an application to a new cancer registry in a developing country

Quality control should be maintained in all disease registries by appropriate statistical procedures to assure complete, accurate, reliable, and timely morbidity and mortality data. Shewhart control charts are recommended for evaluating item completeness. Accuracy and reliability can be evaluated with stringent diagnostic criteria, re-abstraction of records, and statistical measures such as the kappa statistic. Discrepancies between observed and expected data in various time periods can be used to evaluate whether data entering a registry meet timeliness criteria. The reporting delay distribution can be used to examine timeliness of reported data and to adjust incidence rates for potential lack of timeliness in reporting. An application of these quality control procedures is demonstrated using two variables selected from a hospital-based study consisting of 119 breast cancer records collected from the Division of Medical Records, Dr Soetomo Hospital, Surabaya, Indonesia. The results indicate that the variable LASTNAME met the selected criteria for completeness and reliability. The variable ADDRESS met the reliability but not the completeness criterion. All reported cases met the timeliness criterion. The demonstration confirmed the need for registries to establish formal quality control procedures.