PREventing Second Cancers With DOSTARlimab

PredoSTAR is a multicenter, randomized, open-label phase II study proposed to patients at high risk of SPC and in whom the treatment of the FPC does not include immunotherapy. Dostarlimab treatment will be started within 6 months after the completion of treatment for localized FPC (i.e. after the end of last CT, RT cure or surgery with a wash-out period of 4 weeks before to start Dostarlimab). Eligible patients will be randomized (1:1) to receive: * Arm Dostarlimab : 4 intravenous (IV) injections of dostarlimab, Q3W or * Arm No treatment