Rare Cancers

Rare cancers are defined as those with an incidence of fewer than 6 per 100,000 people per year in Europe (Gatta et al 2011), and fewer than 15 per 100,000 people per year in the US (Greenlee et al 2010). In contrast to the definition of rare cancers based on incidence, the definition of rare diseases is based on prevalence, i.e. those that affect fewer than 5 in 10,000 people. In this chapter we will focus on rare adult solid cancers. We will not discuss rare hematological malignancies, nor pediatric cancers.