Misreporting, missing data, and multiple imputation: Improving accuracy of cancer registry databases.

Cancer registries collect information on type of cancer, histological characteristics, stage at diagnosis, patient demographics, initial course of treatment including surgery, radiotherapy, and chemotherapy, and patient survival (Hewitt and Simone 1999). Such information can be valuable for studying the patterns of cancer epidemiology, diagnosis, treatment, and outcome. However, misreporting on registry information is unavoidable, and thus studies based solely on registry data would lead to invalid results. Past literature has documented the inaccuracy of registry records on adjuvant, or supplemental, chemotherapy and radiotherapy. The Quality of Cancer Care (QOCC) project (Ayanian et al. 2003) used data from the the California Cancer Registry, the largest geographically contiguous population-based cancer registry in the world, to study the patterns of receiving and reporting adjuvant therapies for stage II/III colorectal cancer patients. The study surveyed the treating physicians for a subsample of the patients in the registry to obtain more accurate reports of whether they have received adjuvant therapies. This study confirmed the inaccuracy of the registry data in favor of underreporting. PMC ID: PMC2731972 (September 2008)