Degree of coverage and data quality in the Colorectal Cancer Registry
Degree of coverage and completeness
All patients with colorectal cancer in Norway must be included in the registry. The Cancer Registry's basic registry contains information on 99.8 per cent of all patients diagnosed with colon cancer and 99.9 per cent with end-cancer cancer.
All doctors who provide health care to patients with cancer are obliged to report to the Cancer Registry. This includes reporting to the Colorectal Cancer Registry (CCR). Colorectal cancer is assessed and/or treated at all hospitals in Norway, and all hospitals report to the Cancer Registry.
Results for the coverage rate for assessment report and surgery report 2023:
• Colorectal cancer assessment report: 78.9 %
• Colon cancer surgery report: 88.7 %
• Rectal cancer assessment report: 82.0 %
• Rectal cancer surgery report: 89.0 %
In 2023, the colorectal cancer registry and the Advisory board have continued to focus on increasing reporting, but there is still a lower coverage rate for assessment reports than for surgery reports. The well-established collaboration with the contact persons at the hospitals is an important factor for the results. The quality registry also regularly receives inquiries about reporting.
The degree of coverage of clinical reports for each hospital is specified in the CCR's annual report (Norwegian only).
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 completeness of the quality registry is calculated and assessed through annual coverage rate analyses
- 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
- The quality registry annually performs a validity analysis where information on radiation therapy and drug cancer treatment registered in the Cancer Registry is compared with information on radiation therapy and drug cancer treatment registered in the Norwegian Patient Registry
