Familial Cancer in Women from the Gomel Region of Belarus

Breast cancer is the commonest malignancy among women in Belarus. During last 10 years the total incidence of breast cancer has doubled and a change in pathological features was observed. Registered incidence rates were increased in the age groups 30–39 and over 50 years [1]. The Chernobyl nuclear accident caused a unique radio-ecological situation on the territory of Belarus. More then 23% of its territory was contaminated and more then 2 million people live under chronic exposure to low dose irradiation [2]. If we accept the concept of hormesis, there is no threshold dose below which there is risk of radiation-induced cancer. The incidence of any type of cancer may be increased after exposure to radiation, but the risks per centigray are not the same for all organs. Breast, thyroid and bone marrow appear to be the most radiosensitive tissues [3]. According to a “two-hit” model of dominantly inherited predisposition to cancer [4] and to the fact that any dose of radiation can induce cancer [5], it can be suggested that carrier of genes predisposing to breast cancer might be more radiosensitive [6]. However, there are no available data on the influence of low dose irradiation on inherited breast cancer. The clearing up of this question is very important because of the introduction of mammography to screening programmes for high-risk groups, e.g., hereditary breast cancer. In 1990 we started work on familial breast cancer among the populations living in 3 regions of Belarus most affected by Chernobyl (Gomel, Mogilev and Brest regions). The total population of the 3 regions is 4.33 million.