The National Agency for Cancer Registration (NACR) has data on cancer since 1980. Up to and including disease year 2019, Swiss cancer figures are based on projections, as not all cantons have a cancer registry (covering around 90% of the population in 2017).
With the entry into force of the Cancer Registration Act (CRA) in 2020, information on cancer is collected across the board in Switzerland. The CRA has also improved the harmonisation and standardisation of data collection and introduced a reporting obligation, thus achieving a higher quality of data.
In 2022, the NCAR published a concept for ensuring data quality. Based on this concept, the NCAR prepares an annual quality report for the cantonal cancer registries. The data are evaluated for this purpose with regard to their comparability, completeness of the case ascertainment, completeness of cases, correctness and currency. These dimensions are used by default in cancer registration for the assessment of data quality.
The temporal and geographical comparability of cancer statistics compiled for different analysis groups must be ensured. Analysis groups can be multiple cantons, Switzerland compared to other countries, sexes, age groups, different calendar years, etc. Comparability is achieved by complying with national and international guidelines for cancer registration and standardisation of procedures.
Completeness of the case ascertainment
The completeness of the case ascertainment concerns the question of whether all reportable cancer diagnoses in a certain population group have actually been recorded in the databases of cancer registries.
Completeness of cases
The completeness of cases is sufficient if all reportable information on a cancer case, which is documented in medical reports and is reportable in Switzerland, has been transferred to the registry database.
The accuracy (or validity) of registered cancer data refers to the correspondence between the registered information and the information documented in the medical reports.
In order for the cancer registry to contribute to the development and optimisation of the healthcare system, the registered information must be sufficiently up to date. The currency corresponds to the time between the diagnosis and the date on which the case is included in the cancer statistics.