Forms and instructions

 

Cancer registration in Finland

Text modified from:
Pukkala E. Finland – cancer registration. In: Pukkala E, et al. Cancer atlas of Northern Europe. Cancer Society of Finland Publication 62, Helsinki 2001, pp. 50-51.

Cancer registration in Finland started in 1952. In the 1950s, the reporting of cancers and certain benign tumours was voluntary. In 1961 the National Board of Health issued a by-law making such reporting compulsory. All physicians, all hospitals and other institutions in the country must send a notification to the Registry of all cancer cases that come to their attention. Pathological, cytological and haematological laboratories send the respective  laboratory notification. An increasing number of notifications, especially from the pathological laboratories, but also from hospitals, are currently sent in machine readable format. The automatic reporting contains the same information as the manual reporting forms, including in the free texts detailed descriptions of the tumour site and histology.

In addition, Statistics Finland annually sends a computerised file on death certificates in which any malignant disease is mentioned.

Both public and private institutions co-operate well. The Finnish Cancer Registry and its staff are highly recognised both among the scientific community and the health care sector in Finland. The output of the Registry is widely used in research, administration, and health education on all levels.

All this improves the quality of the registration activity and is likely to contribute towards complete coverage and high data accuracy in the Registry.

Primary medical care in Finland is provided to the entire population for only nominal fees. After initial visits to a general or specialist practitioner, cancer patients are usually referred to a hospital for confirmation of the diagnosis and treatment. Patients are referred from one hospital to another according to the needs for diagnostic examination and/or treatment.

Every patient diagnosed with cancer can be considered to be in a position to receive adequate modern cancer treatment, if such treatment is indicated. There are oncology units (with radiotherapy facilities) in the five big university hospitals and four other (regional) hospitals. Cancer surgery is practised in many general hospitals.

Everyone who has resided  in Finland since 1967 has been assigned a unique 11-digit personal identity code (PID), which is widely used in a number of different everyday events (including health care), and in all important person registers. The PID of the patient is indicated on all cancer registry notifications, and it is stored in the Registry database. It is the key in all practical registration procedures: e.g., in coding, searching from the file, and combining notifications for one patient received at different times and from different sources. For example, duplicate registration can thus be effectively avoided. PIDs have greatly facilitated record linkage operations in Finland, and large and complicated computer runs can be executed very rapidly and in a reliable way.

The following diseases are reported to the Registry:
    • all malignant neoplasms, such as carcinomas, sarcomas, malignant lymphomas, leukaemias, multiple myeloma, gliomas, melanoma, etc.);
    • carcinoid tumours, pheochromocytomas, thymomas, ameloblastomas, and chordomas;
    • carcinoma in situ lesions (except those of the skin);
    • CIN III and CIL III of the cervix uteri; histologically benign tumours of the central nervous system and meninges, transitional cell papillomas of the urinary tract, and ovarian tumours with borderline malignancy.
The Registry file is annually matched, through computerised record linkage (based on PIDs), with the Cause of Death Register located at Statistics Finland, so that the dates and causes of death (also non-cancerous causes, both underlying and contributory causes of death) can be added to the records in the Registry.

The Registry file is also regularly linked with Central Population Register where the correctness of the PIDs is checked, and the complete name, vital status, possible date of death or emigration as well as the official place of residence prior to the date of diagnosis are obtained.

The cancer notifications submitted to the Finnish Cancer Registry are immediately stored to the database at the Registry. Thorough visual and automatic checking procedures are carried out, both at data entry and coding. The computer directly announces illegal codes and code combinations, as well as illogical order of dates (of diagnosis, start of treatment, and death). Specific checks are carried out when needed, e.g., completeness of the Registry has been evaluated in comparisons with the national Hospital Discharge Registry [1].

If only laboratory and/or death certificate information is available, or if the data on the primary site of the tumour or date of diagnosis are incomplete or controversial, requests for further information are sent to the hospitals and physicians. This procedure is successful in a high proportion of the requests.

Final coding of cancer data is done by qualified secretaries and supervised by the Registry physician (pathologist). The Registry has followed a slightly modified version of the ICD-7 nomenclature from 1955 for coding the primary site of cancer. However, during 2005 Finnish Cancer Registry will go over to the ICD-O-3. For histology, the 2-digit codes of the American Cancer Society from 1951 are being applied so far, slightly extended to meet the demands of the later decades. In the future the ICD-O-3 will also be followed for morphology. In practice it has been shown that it is not very important which coding system is used: virtually any specific disease category can be formed on the basis of the existing data. This also allows relatively precise conversion of old codes to ICD-O-3 back to the year 1953.

Each cancer considered to be an independent new primary lesion is registered separately. All independent cancer processes are coded as separate entities. The Registry files contain about 950,000 cancer cases diagnosed in 1953-2004. In addition, there are a number of cases diagnosed prior to 1953 in persons who died from cancer or got a new primary cancer since 1 January 1953. More than 22,000 new cases of cancer are currently registered each year, plus some 4,500 basal cell carcinomas of the skin and smaller amounts of some other lesions, which in the published statistics are usually excluded from the total numbers of cancers [2].

The following coded items usually meet the needs of producing statistics and doing analytical research:
    • name and PID,
    • municipality of residence,
    • primary site and date of diagnosis,
    • basis of diagnosis,
    • stage: localised, regional metastases, distant metastases,
    • malignancy: malignant, microinvasive (cervix uteri), in situ, borderline (ovary), benign (intracranial, urinary tract), or to be excluded from basic statistics (basalioma, polycythaemia vera, myelofibrosis, etc.),
    • histology/cell type,
    • treatment: surgery, radiotherapy, cytotoxic drugs, hormones, other; specific codes for curative/palliative surgery or radiotherapy; specific codes for primary treatment and later treatment,
    • follow-up: date of death or emigration, cause of death.
All data received by the Registry on individual cancer patients remain on the computerised database. In addition to the items listed above, for instance names of the notifying hospitals or laboratories,  specimen numbers, tumour grade, TNM classification, site of metastases, details of the treatment, or cause for not being treated can, if needed, be used for different purposes, e.g., for searching the histological slides for re-evaluation.

The Finnish Cancer Registry compares the official causes of death of each cancer patient (transferred from Statistics Finland through an automatic record linkage procedure) to all data available for that cancer, and evaluates whether the patient died from that cancer or something else. The cancer mortality
rates refined by the Cancer Registry allow the use of more detailed classifications of the cancer itself than the official ones produced by Statistics Finland. Since the 1980s, the official rates have been very close to the refined ones.

The Finnish Cancer Registry has emphasised the importance of data protection and personal privacy years before it became an issue of debate in Western societies. No violations of the individuals' privacy have occurred in the over 50  years of cancer registration in Finland. Data on the level of individuals can be delivered to researchers working outside the Registry only through permission given by the National Research and Development Centre for Welfare and Health (within the Ministry of Healthand Welfare). Every year about 80 scientific papers are published based on the data and know-how of the Finnish Cancer Registry [2].

The newest cancer statistics (incidence, mortality and prevalence) can always be found at the home pages of the Finnish Cancer Registry (www.cancerregistry.fi).

References

[1] Teppo L, Pukkala E, Lehtonen M. Data quality and quality control of a population-based cancer registry
  • experience in Finland. Acta Oncol 1994;33:365-9.

    [2] Finnish Cancer Registry
  • Institute for Statistical and Epidemiological Cancer Research. Cancer incidence in Finland 2000 and 2001. Cancer Statistics of the National Research and Development Centre for Welfare and Health. Cancer Society of Finland Publication 65, Helsinki 2000.