Background: The aim of the work is to assess the probability of the breast cancer occurrence on the basis of analysis of the clinical and mammographical factors in women with unpalpable breast tumor. Material/Methods: In the period from the 1st February 1995 to the 31st August 2000, 163 surgical procedures for the removal of any lesions in the breasts were conducted, after being previously marked by localized needle, in women who earlier underwent mammography exam.Following data was taken into consideration: patients age, type of the breast structure; side of the breast, where the lesion was localized in the mammography exam; localized lesions depending on the quadrant; shape of the lesion; size of the lesion in millimeters; presence and the type of microcalcifications. Results/Conclusions: 1. The only one population factor, which can be distinguished as characteristic for the women suffering from the breast cancer impalpable in clinical testing, is the age of the patient, because the breast cancer in these women more frequently occurs after 53 years of age. 2. On the basis of our own material the following radiological symptoms characteristic for the breast cancer in mammography exam were stated: the breast cancer is more frequently found in the upper external quadrant; all lesions, which in mammography exam were identified as multifocal and radiologicaly suspected in histopathology exam turned out to be the cancer; pleomorphic microcalcifications are characteristic for the malignant lesions; external outline and the shape of the lesion are the features, which allow to differentiate malignant and benign lesions. 3. The analysis of the material indicates that the greatest probability of the breast cancer occurrence is in case of the four risk factors occurrence simultanosly, and the smallest in case of only one risk factor occurrence
