HEAD AND NECK-CANCER IN NORWAY - A STUDY OF THE QUALITY OF THE CANCER-REGISTRY-OF-NORWAY DATA ON HEAD AND NECK-CANCER FOR THE PERIOD 1953-1991

Data from population-based cancer registries provide information on th e causes and outcome of cancer and form a basis for important decision making in connection with the prevention of cancer and the planning of health services. This makes it of the utmost importance to assess the data at all stages of collection to ensure the highest possible quali ty. The present study focuses on the quality of the Cancer Registry of Norway's data on head and neck cancer for the period 1953-1991. When the study was started, 16,104 cases of head and neck malignancies had been registered. Al histological codes were reviewed. The pathologists ' reports were reevaluated for 369 cases selected according to set cri teria: 133 cases received a new histological code without being exlude d from the data material; 112 cases were excluded. The distribution of histological diagnoses for each location is presented. A reevaluation of 300 cases selected at random from the corrected series indicates d iscrepancies between the pathologist's classification and the Registry 's coding in less than 2% (1.4%) of all cases. The percentage that lac ked histological verification fell from 5.7% in the first decade to 2. 1% during the last 9-year period. Completeness of the Cancer Registry' s data base was checked against hospital-based registries and this inv estigation showed that virtually all new cases are reported. We conclu de that the data on head and neck cancer for the studied time period m eet standards that justify their use as a basis for epidemiological as well as clinical studies.