Belarus
Aleksei Okeanov, Semion Poliakov
The Republic of Belarus is situated in the centre of Eastern Europe between 51o16' and 56o10'N and 23o11' and 30o35'E. It borders Lithuania and Latvia in the north, Poland in the west, Ukraine in the south and Russia in the north and east. The total area of Belarus is 207,600 km2. It stretches for 560 km from north to south and 650 km from west to east. Most of Belarus is flat country, the highest point being 345 m. There are nearly 3000 rivers and 4000 lakes in Belarus, the largest of which is Naroch. One quarter of its area is covered with forests which are mostly coniferous. The climate is a moderate continental one with a mean annual temperature ranging from 4o in the northeast to 7oC in the southwest. The mean January temperature ranges from 4o to 8oC, in July from 17o to 18.8oC. The mean annual precipitation is 550-700 mm. The capital city is Minsk (population 1613 thousand according to 1989 census), and it is located in the centre of Belarus. There are 6 regions (oblasts) in the Republic (Brest, Grodno, Gomel, Minsk, Mogilev and Vitebsk). 14 cities have a population of more than 100,000, and 84 towns have more than 10,000. The country's total population is 10.2 million (65.5% of it urban). The male population is 46.8% and female 53.2%. The ethnic composition includes 77.9% Belarussians, 13.2% Russians, 4.1% Polish, 2.9% Ukrainians, 1.1% Jews, and 0.8% other. There are 5.1 million employed persons (1990) among the population, with 31% of them working in industry, 19% in agriculture, 17% in health services, physical recreation, social security, education, science, culture and arts, 11% in construction, and 7% in public catering, state purchase, supply and sales [1]. The main branches of industry are machine building and metal processing, including automobile and tractor building (Minsk, Zhodino, Mogilev), radio electronics, oil refinery and chemical industries (Grodno, Svetlogorsk, Mogilev and Novopolotsk). Life expectancy at birth in 1981-1990 was 67 years for males and 76 for females. In 1985-1990 the ratio of live births to legal abortions was 1:1.5. The mean birth rate in 1981-1990 was 16, and the death rate was 10 per thousand. The infant mortality rate for this period was 14 per thousand live births. The leading causes of death in 1985-1990 were cardiovascular diseases 55%, tumours 10%, injury and poisoning 10% [1]. The Chernobyl accident happened in 1986, which exposed 1/5 of the Belarusian population to radiation. The Chernobyl accident was the largest in the history of nuclear power and had large-scale environmental consequences. At the time of the accident at the Chernobyl Power Plant about 4 tonnes of nuclear fuel was emitted from the reactor containing 190 tonnes into the environment (more than 1018 Bk of Iodine, Caesium, Cerium, Barium, Strontium, Plutonium and other radionuclides). This is thought to have had a serious health impact on the population.
Cancer registration
The registration of cancer in Belarus has been carried out since 1953. However, because of the small number of cancer hospitals it was not complete in the 1950s and 1960s. Efforts to improve the cancer registration were undertaken at the end of the 1960s and beginning of the 1970s. The first sufficiently complete statistical data were obtained in this period. In 1973 the central computerised cancer registry began to function in Belarus (at that time Byelorussian SSR) in the Institute for Oncology and Medical Radiology. Since 1992 it has been functioning in the Belarusian Centre for Medical Technologies. It was based on special forms called 'Card of dispensary control (onco)' filled in and coded in each of the 12 oncological dispensaries. Once a year all these forms were transferred to computer media (cards, paper tape, magnetic tape) and then, after a strict computer check, were entered into the computer. Following the processing of the data, an annual file was created on magnetic tapes and disks. The Belarusian Cancer Registry has had such files since 1978. These files contain the information on new cancer cases, on living cancer patients registered in the preceding years, and on deceased cancer patients within the incidence year. Until 1985 the information stored in the computer files had no names and addresses of persons with cancer diagnoses. This produced some difficulties in data correction and specification. In 1985 a computer system of dispensary control for cancer patients was set up in the oncological dispensaries in Belarus. This system made it possible to solve problems concerning longterm continuous data collection on patients and made their follow-up easier. Since 1991 this system has functioned on personal computers in all the Belarusian oncological dispensaries. The registry collects information about the cancer situation in the whole country. In each rayon (administrative subdivision of a region) of Belarus, and also in every city outpatient clinic, there is an oncologist who is responsible for all cancer patients of his or her area. In each case when cancer is suspected he or she should direct the patient to the regional specialised oncological hospital (oncological dispensary) for further examination. Any medical institutions where a cancer case was diagnosed should fill in a special notification form and send it to the oncological dispensary. The pathologists should also send notifications in cases of incidentally diagnosed cancer during an autopsy [2]. It should be noted that in Belarus more than 85% of treated cancer patients are treated in oncological dispensaries, making the collection of data signifificantly easier for the Institute for Oncology and Medical Radiology. Every dispensary has a special department that collects data from all cancer cases in the region, including the cases diagnosed after death, and maintains the computerised data base. Most of the required information is entered into computer directly - from the patients' medical records kept in the dispensary. Since 1985 all tumours has been coded according to the International Classification of Diseases of the 9th revision (ICD-9) of the World Health Organisation adopted for the Belarusian Cancer Registry. All previous files were also converted to ICD-9. For coding histology the local classification is used. Quality control is usually undertaken to estimate completeness and accuracy of the data. The data is considered complete if all fields in a personal file are filled in. A search for new cancer cases in the hospital is not foreseen, as all health care institutions are to report all the diagnosed and/or treated cancer cases to the oncological dispensary. The correspondence of data is checked in some aspects by special software: correspondence of dates, site and sex, etc. If the personal data is incomplete, inquiries to the local outpatient clinic in the place of the patient's residence are made to find out the necessary details. Follow-up of patients is carried out in the following way. Each patient is registered in the local regional cancer dispensary after a cancer diagnosis and/or treatment and periodically is invited for medical examination. If the patient doesnąt come, inquiries are made to the local outpatient clinic to find out the reason for it. If the cancer patient has moved away or died the information is sent to the oncological dispensary. Additionally, the staff of this department checks the records every month of the regional population statistics bureau, which has all death certificates, in order to find additional information on cancer cases. During this check they also can find the information about death of the known patients. Each previously unknown cancer case which is discovered in this check is followed up by sending a letter to the treating hospital, inquiring for more detailed information. The Belarusian Cancer Registry registers all cases of malignant neoplasms, including diseases of lymphatic and hematopoietic tissues, and carcinoma in situ. Each person included in the registry file is identified by region code, dispensary code, date of registration, and registration card number. Each tumour is recorded separately within the personal record of a patient, allowing a correct count of all the cancer cases. Independent primaries are defined as tumours of different organs or different parts of organs, according to four-digit ICD-9 classification. Multiple tumours of the skin are counted separately for different sites. Only of 0.4% cases are based on death certificate only. The mean percentage of histologically / cytologically verified cases for Belarus is about 70%, with some variation between regions (ranging from 78% in the Gomel region to 60% in the Minsk region) and sites. The data on cancer mortality were obtained from the cancer registry database, including date and cause of death. The comparison of the accuracy between official cancer mortality statistics and the cancer registry data showed that the latter was more reliable.
References
1. Population of the Republic of Belarus. Ministry of Statistics and Analysis, Minsk, 1995
2. Storm HH, Prisyazhniuk AE, Okeanov AE, Ivanov VK and Gulak L. Development of infrastructure for epidemiological studies in the three CIS republics. First International Conference of the European Commission, Belarus, the Russian Federation and the Ukraine on the radiological consequences of the Chernobyl accident (Minsk, Belarus, 1822 March 1996). IOS Press, Amsterdam, 1996.