Observation and/or Combination Chemotherapy After Surgery or Biopsy in Treating Young Patients With Extracranial Germ Cell Tumors

RATIONALE: Sometimes, after surgery, the tumor may not need additional treatment until it progresses. In this case, observation may be sufficient. Drugs used in chemotherapy work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving more than one drug (combination chemotherapy) may kill more tumor cells. Giving combination chemotherapy after surgery may kill any remaining tumor cells. PURPOSE: This phase III trial is studying how well observation and/or combination chemotherapy works after surgery or biopsy in treating young patients with extracranial germ cell tumors.