The European Reference Network: the keystone for the management of rare thoracic cancers.

© Mediastinum. All rights reserved. Mediastinum 2023;7:7 | https://dx.doi.org/10.21037/med-22-10 Rare tumors are a heterogeneous group of malignancies, which show an incidence rate of <6 per 100,000 people per year, according to the definition of Surveillance of Rare Cancers in Europe (RARECARE) (1). Overall, the estimated incidence of all rare tumors in Europe accounts for 24% of all cancers, with 5-year relative survival for all rare cancers of 48.5% (2). Indeed, rare thoracic tumors include many entities: epithelial tumors of the trachea, rare epithelial tumors of the lung, epithelial tumors of the thymus, malignant pleural and pericardial mesothelioma, mediastinal germ cell tumors and mesenchymal tumors (Table 1) (1,3-5). The incidence of these tumors in Europe is the highest in patients aged 65 years and older, with a crude rate of 1.4 per million per year for the epithelial tumor of the trachea, 1.7 per million per year for thymic epithelial tumors, among which malignant thymomas are the most common, and 16 per million per year for the malignant mesothelioma of pleura and pericardium. The 5-years relative survival rate is 14% for the epithelial tumors of the trachea, 65.6% for thymic epithelial tumors, and 5.4% for malignant mesothelioma (5). Detailed data on incidence, prevalence and survival of several types of rare thoracic tumors included in Table 1 were reported in a study of the RARECARE working group, using a large patient database (5). These malignancies present an intrinsic complexity in clinical management, both in the initial diagnostic phase, as well as in the treatment choice, due to scarcity of clinical practice guidelines and also to the lack of randomized clinical trials, which substantially limit treatment options. Moreover, to reduce the diagnostic delay and to improve the appropriateness of treatment choice, clinical centers with adequate patient volumes and expertise should be homogeneously accessible in different geographical areas, also to reduce healthcare migration (3,6,7). Notably, the clinical complexity of rare thoracic tumors systematically requires multidisciplinary team discussion to reach the correct diagnosis and offer the best treatment. In 2008, the European Commission launched the RARECARE project. This is a population-based cancer registry aiming at defining incidence, prevalence and long-term outcome of rare cancers. This project allows to study the epidemiology of these cancers in a large and heterogeneous population (8,9). The results of RARECARE registry led to a second project (RARECAREnet), which updated and enlarged the available information on rare cancers in Europe (10). In addition, the Joint Action on Rare Cancers (JARC) launched in 2016, is another major European initiative, in which 34 partners from different countries belonging to the European Community are involved. This project, coordinated by the National Cancer Institute of Milan (INT), seeks to improve the epidemiological knowledge of rare cancers, to offer education to healthcare professionals and to ameliorate clinical management of these diseases, promoting the integration of translational research Editorial Commentary