National Cancer Register

It is compulsory for every health care provider to report newly detected cancer cases to the registry. A report has to be sent for every cancer case diagnosed at clinical-, morphological-, other laboratory examinations as well as cases diagnosed at autopsy.

Since the mid-80’s there are six regional registries associated with the oncological centres in each medical region of Sweden where the registration, coding and major check-up and correction work is performed. The regionalization implies a close contact between the registry and the reporting physician, which in turn simplifies the task of correcting and checking the material.

Information available in the National Cancer Register

There are three different types of information:

1. Data on the patient

• Personal identification number
• Sex
• Age
• Place of residence

2. Medical data

• Site of tumour. For the years 1987–1992 the tumours has primarily been coded in ICD-9 and from 1993–2004 in ICD-O/2. From 2005 the cases has been coded in ICD-O/3. For the whole period 1958-w the codes are available as ICD-7 codes.
• Histological type. For the period 1993-2004 according to ICD-O/2. From 2005 in ICD-O/3. For the whole period 1958-w the codes are available as the old histology code (WHO/HS/CANC/24.1).
• Stage has been collected since 2004. Stage is not recorded for brain, cranial nerves, lymphoma and leukaemia. Gynaecological tumours are coded according to FIGO and the rest according to TNM (latest edition).
• Basis of diagnosis
• Date of diagnosis
• Reporting hospital and department
• Reporting pathology/cytology department
• Identification number for the tissue specimen

3. Follow-up data

• Date of death
• Cause of death
• Date of migration

Reporting procedures

The regional registries send information about newly registered cases and correction concerning those previously reported to the National Cancer Register on an annual basis. 

Quality of data and underreporting 

The material passes through the following controls:

• The identification number is checked against the register covering the total population of Sweden.
• Duplicates are subject to special checking.
• The validity and logical contents of the codes are checked when the material is processed, for example sex and site.

A quality study of the cancer register (then the Swedish Cancer Register) was published in Acta Oncologica in 2008 (The completeness of the Swedish Cancer Register – a sample survey for year 1998 by Barlow et al.) where the coverage rate was evaluated in comparison to the inpatient registry. The underreporting was then estimated to approximately 4 percent.

An estimation of the underreporting of cancers can also be done by comparing the National Cancer Register data with the National Cause of Death Register, since the National Cancer Register does not accept notifications from death certificates. This shows that underreporting is highly dependent on the cancer site; for example breast cancer has very low underreporting while there are a larger number of pancreatic and lung cancer not reported to the cancer registry.

Contact the National Cancer Register

If you have questions about the National Cancer Register, you can contact us at cancerregistret@socialstyrelsen.se.