Breast cancer is the most frequently diagnosed malignant neoplasm among females. The proportion of women diagnosed in the premenopausal period is relatively small. Nevertheless, this is the most commonly diagnosed cancer among young women. The aim of the study was to analyze the incidence rate of breast cancer in a group of young women based on data obtained in the Lower Silesian Voivodeship between 1984 and 2016. A total of 34,251 women with a diagnosis of invasive breast cancer were analyzed. The median age of diagnosis exhibited an upward trend from 57 to 63. The youngest age of breast cancer diagnosis did not decrease. Women up to the age of 24 were sporadically diagnosed. Given the total number of cases, the proportion of women under the age of 39 was approximately 5%, and it did not increase throughout the entire examination period. The major increase in the growth trend during the analyzed period was observed in a group of women aged of 50-69 (regression coefficient: +24.9) and above 70 (regression coefficient +21.2). In a group of women under 40 the regression coefficient was only +4. It seems that breast cancer does not increasingly affect younger women since the risk in this age group remains low. However, an increasing incidence rate of breast cancer is more commonly observed in premenopausal women.
Keywords: breast cancer; incidence; screening; young women.