Degree of coverage and data quality

All doctors who provide health care to patients with cancer are obliged to report to the Cancer Registry. This includes reporting to the Norwegian Registry of Brain and Spinal Cord Tumours.

For the year 2022, 652 new cases of histologically verified primary tumors of the brain, spinal cord and spinal canal, as well as brain and spinal cord membranes have been recorded. Because of the low coverage of the clinical report, it is the histologically verified tumours that mainly constitute the data basis for all analyses in this annual report.

Coverage is meant the proportion of patients registered in the Cancer Registry of Norway in 2022 who have a clinical report. For example, the coverage rate for clinical assessment reports is calculated as the proportion of all cases diagnosed in 2022 where an assessment report has been received and registered. The same may also apply to the degree of coverage of clinical treatment reports where the denominator will come from pathology reports or the Cancer Registry's radiation database, both of which are considered to be almost complete sources.

During the preparation of the annual report, we found that the reporting of tumours in the brain, spinal cord and spinal canal, brain and spinal cord membranes and pituitary gland, which has not been histologically verified, is inadequate. We have therefore not estimated the completeness of these tumours in the Cancer Registry of Norway in this report. Figure 5.1 from the annual report (Norwegian only) shows that the clinical notification coverage rate for patients with a histologically verified tumour is 33.1 % for the country as a whole.

The coverage is low and far below both moderate (yellow) and good (green) goal attainment. None of the four health regions have achieved satisfactory goals. Increasing the reporting of clinical reports is therefore a focus area for the Norwegian Registry and the professional council in 2023.

Data quality

Quality assurance of data is done as an integral part of the coding and registration process. In addition, the following examples help to ensure data quality in the Cancer Registry:

• Several independent sources report information
• The information is reported at several points in the course of the disease
• The employees have unique expertise in coding cancer cases according to the Cancer Registry's own code book and international coding systems
• IT systems have rules and barriers for illogical combinations, incorrect information and more
• The Cancer Registry of Norway conducts analyses and control runs that reveal inconsistency in the data
• Data extraction for researchers makes it possible to check a smaller data set of information that can reveal individual errors (e.g. incorrect entry of hospital codes) or systematic differences due to different interpretations of coding systems and rules