Metastatic breast cancers: Estimates for Italy

Breast is the leading site of cancer onset and death in Italy. Cases diagnosed in stage IV or that progress in metastatic phase represent a specific and challenging task for oncologists. Estimates on the burden of breast cancer (BC) in stage IV in Italy are not available. We applied mortality-incidence age-specific ratios measured in the United States in 2013 for BC in stage IV at diagnosis (de novo) or following a previous diagnosis in a localized stage (distant recurrence) to the age-specific BC deaths observed in Italy in 2014. The US mortality-prevalence age-specific ratios were used for estimating de novo and distant recurrence prevalent metastatic BC. In 2014 in Italy, there were 12,330 deaths due to BC. We estimated that in the same year about 3400 BC were newly diagnosed in stage IV (7.1% of all the new cases); moreover, more than 10,000 other BC progressed to stage IV. In addition, in 2014, the overall number of BC in stage IV, whenever diagnosed, was about 37,100 (5.6% of all the estimated prevalent BC). These estimates quantify, for the first time in Italy, the burden of BC in stage IV, at diagnosis or during the clinical course, providing useful figures for clinicians and policy makers