Children with the inherited form often
  develop tumors in both eyes and may develop
  other malignancies later in life, such as
  sarcomas, leukemia or melanoma. 
• In children with the spontaneous form, the
  tumor cells also have defects involving both
  RB genes, but these defects have not been
  inherited. These children usually have only
  one tumor and are not predisposed to develop
  other cancers.
      If detected early, both inherited and
  spontaneous forms of retinoblastoma are
  curable with radiotherapy , and vision can be
  preserved. Genetic probes can detect the
  abnormal RB gene, identifying children at risk.
  These children need careful clinical monitoring
  and frequent eye examinations.