The prevention of hereditary breast cancer in Italy: towards the implementation of the national prevention plan in the Italian regions

Breast cancer is the malignant cancer with highest incidence in females, representing 29% of all cancers, followed by colorectal cancer (13%), lung cancer (6%), thyroid cancer (5%), and uterine body cancer (5%). It has been estimated that in Italy almost 48,000 women were be affected in 2015. The majority of breast cancers shows a multifactorial pathogenesis, however 5-7% shows a strong hereditary component, namely genetic factors that follow mendelian inheritance mechanisms. In fact, among affected woman, almost 2% of breast cancers is determined by genetic variants of BRCA1 and BRCA2 (“BRCA genes”), that show an high penetrance pattern of hereditary predisposition. Nevertheless, when considering only affected women younger than 40 years, the percentage of carriers of pathogenic variants BRCA genes rises up to 10%. The prevalence of pathogenic variants of BRCA genes in the Caucasians is around 1/400. When applying this frequency to the whole Italian resident population in 2015, it can be estimated that in our country almost 152,000 people are carriers of these variants, and can therefore be at higher risk to develop breast cancer. In fact, the median estimate of cumulative risk of breast cancer in 70 years-old women is 57% for carriers of BRCA1 variants and 49% for BRCA2. Moreover, carriers of pathogenic variants show a tendency to develop breast cancer at earlier age, and are also at increased risk of ovarian cancer (lifetime risk is 40% and 18% for carriers of BRCA1 and BRCA2 variants, respectively