An overview: ongoing systemic therapy trials in thymic epithelial tumors around the world-will anything "hit"?

Thymic epithelial tumors are rare malignancies requiring multidisciplinary management. Systemic treatments are part of this global approach in both locally advanced cases—for which combined strategy is needed—and metastatic disease, using standard chemotherapy. Current systemic treatments are insufficient, and the prognosis of advanced disease remains poor. Treatments mostly derived from general oncologic research and we lack specific thymic tumors targeting drugs to develop precision medicine strategies. Many thymic tumors systemic therapy trials are currently ongoing around the world, facing the difficulties of rare disease research and management: lack of biomarkers, lack of patients, difficulties in establishing good landmarks and wise endpoints... To be able to hit, those trials have to fit some prerequisites. The clinical needs have to be identified clearly. Trials have to be built with adequate endpoints, good selection of patients and integration of well-defined biomarkers. Those criteria allow the selection of trials that will possibly ultimately hit in any situation in which systemic treatments are required in the management of thymic tumors. This concerns primary treatment—systemic treatment in association with local treatment in a curative intent strategy; exclusive treatment—first line systemic treatment administered alone in thymic tumors no accessible to local treatment (surgery or radiotherapy); treatment for recurrences—systemic treatments administered in recurrent diseases not accessible to local management. Given the rarity of thymic tumors, building up trials remains a real challenge and few trials meet the strict conditions to be able to finally hit. The easiest way to overcome all those difficulties is probably to aim at a more collaborative approaches through international trials, tumor boards and multidisciplinary interactions.