again and more therapy is needed. But sometimes chemotherapy is continued indefinitely—maintained
  remission—until a relapse occurs, at which time the drug program will be changed.
• For programs in which chemotherapy is combined with radiotherapy , specific rules and formulas apply to
  each treatment protocol—prescribed doses, schedules and drug combinations—which are generally followed
  exactly.
• There are similar standards for adjuvant chemotherapy programs for patients who have a high risk for
  recurrence . The therapy to wipe out small nests of cancer cells that cannot be detected is generally given for
  six months to one year.