This is a prospective multicenter, non-randomized research program that includes:
* a phase IV study (for all patients) with a collection of tissue specimens of tumor, * a phase II study (for patients with primary mediastinal tumors and an unfavorable decline in tumor markers), * and a diagnostic study (for all patients, except patients with brain metastases at baseline or patients for whom any brain MRI is contra-indicated).
The main question it aims to answer is improving outcome for young adults with poor-prognosis Non Seminomatous Germ Cell Tumor (NSGCT) is to validate prospectively the efficacy and safety of a personalized treatment based on early tumor marker kinetic assessment in real life for patients with poor-prognosis NSGCT.
Participants will be followed-up according to the assessment of decline kinetics of the tumor markers at the end of a first chemotherapy cycle and according to the localisation of the primary lesion if unfavorable.
* In the case of a patient with a favorable decline of the tumor markers, he will be treated by 3 additional standard chemotherapy cycles. * In the case of a patient with a testicular or peritoneal primary tumor and an unfavorable decline of the tumor markers, the patient will be treated by a dose-dense standard therapy. * The patient with a mediastinal primary tumor and an unfavorable decline of the tumor markers will be proposed to enter the phase II part of the study or to enter the dose-dense regimen like the other primary localisations. If the patient consents and is eligible for phase II part, he will undergo either an early surgery if feasible or a high-dose chemotherapy if the early surgery is not possible.
Male patient older than 16 years old on day of signing informed consent
Patient with evidence of NSGCT based on histologic examination or based on clinical evidence and elevated serum hCG or AFP levels (in case of clinical emergency, therapy can be started before pathologic sample is obtained if tumor markers are highly elevated)
Patient with testicular, retroperitoneal, or mediastinal primary site
Patient with evidence of disseminated disease (clinical stages II or III according to AJCC 8th edition)
Patient infected by the Human Immunodeficiency Virus (HIV)
Patient under guardianship or deprived of his liberty by a judicial or administrative decision or incapable of giving its consent
Patient with prior chemotherapy. Patients who have received a first cycle of cisplatin-base chemotherapy (BEP) for their poor-prognosis NSGCT are eligible as far as tumor marker decline can be assessed at day 18-21.
Patient with previous malignancy, except for basal-cell carcinoma of the skin