<prompt> A case of Gestational trophoblastic neoplasia is detected to have lung metastasis. She should be staged asStage - IStage - IIStage - IIIStage - IV  <response>: FIGO staging system of GTN: Stage I: Disease confined to the uterus Stage II: Gestational trophoblastic tumor GTT extends outside of the uterus but is limited to the genital structures ovary, tube, vagina, and broad ligament Stage III: GTT extends to the lungs, with or without known genital tract involvement Stage IV: All other metastatic sites 