Chemotherapy With or Without Radiation Therapy or Observation in Treating Young Patients With Advanced Retinoblastoma Who Have Undergone Surgery to Remove the Eye

RATIONALE: Drugs used in chemotherapy, such as carboplatin, vincristine, etoposide, and cytarabine, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells. Giving chemotherapy with or without radiation therapy after surgery may kill any tumor cells that remain after surgery. Sometimes, after surgery, the tumor does not need more treatment until it progresses. In this case, observation may be sufficient. PURPOSE: This clinical trial is studying how well chemotherapy with or without radiation therapy or observation works in treating young patients with advanced retinoblastoma who have undergone surgery to remove the eye.