Rare cancer is a term based on the frequency of the disease. More specifically, the Surveillance of Rare Cancers in Europe (RARECARE) project proposed that cancers should be designated as rare when their incidence is lower than 6 per 100,000 population per year [1]. Despite though, each rare cancer is infrequently encountered within the population, rare cancers in total, currently affect 4 million people in the European Union. Furthermore, 500,000 patients are diagnosed with rare cancers, annually, representing 20% of new cancer diagnoses [2]. This number far exceeds annual lung cancer diagnoses (approximately 320,000), indicating that a special interest should be given to this group of cancers.Rare cancers are characterized by specific challenges, both for clinicians and the health systems in general. Patients with rare cancers have lower 5-year survival rates and less improvement in survival the last two decades, in comparison to those with more common cancers [3]. This reflects the lack of experience with rare cancers among clinicians, having as a consequence, not only delays in the diagnosis, but also uncertainty in the management of these patients. Usually, there are very few experts for rare cancers who could provide advice on diagnosis and management. In most of the countries studied, centers of expertise are rare, and these cases are diluted within the community. As a consequence, the interest for research in rare cancers is lacking, there are limited registries of rare cancer cases and corresponding biobanks that could support research efforts. The research in the field of rare cancer suffers the same fragmentation of areas in general health system, but the consequences are more pronounced here.