The purpose of the study is to evaluate the ration of patients getting an lighten therapeutic strategy after 18F-fluoro-désoxyglucose positron emission tomography (PET-TDM) in grade I (cohort 1) or metastatic (cohort 2) seminoma

Inclusion Criteria shared:

• Histologically proved seminoma after orchiectomy
• Primary testicular or retroperitoneal
• Normal alpha-fetoprotein before and after orchiectomy
• No prior treatment with radiotherapy or chemotherapy
• Age >= 18 years
• ECOG 0 to 2
• PNN >= 1500, platelets >= 100 000, bilirubin <= the upper limit nromale
• ASAT (SGOT) and ALAT (SGPT) <= 1,5 x the upper limit nromale
• Serum creatinine <140 µmol / L (or clearance> 60 mL / min)
• Information and signed informed consent before inclusion in the study
• Patient affiliated to a social security

Specific inclusion criteria for cohort 1:

• grade I

Specific inclusion criteria for cohort 2:

• grade IIB (retroperitoneal adenopathy diameter between 2 cm and 5 cm, regardless of the LDH)
• grade IIC (retroperitoneal adenopathy diameter higher than 5 cm, regardless of the LDH)
• grade III of good prognosis (supradiaphragmatic reach with ganglionic metastasis and LDH < 2 times normal limit and/or supradiaphragmatic reach with pulmonary metastasis and LDH < 2 times normal limit) either at initial diagnosis or relapse of a grade I seminoma)
• PET-TDM positive (pathological fixation on metastatic lesions)

Exclusion Criteria shared:

• Patient infected by HIV, Hepatitis B or C
• History, within 5 years, of cancer other than seminoma, except for treated skin cancer (Basal Cell) .
• visceral metastasis
• cerebral metastasis
• Any physical or mental condition incompatible with the treatment (to the investigator discretion)
• Uncontrolled or severe cardiovascular pathology
• Uncontrolled or severe hepatic pathology
• Persons deprived of liberty or under guardianship
• Unable to undergo medical monitoring due to geographical, social or psychological reasons