There are three main reasons for routine follow-up examinations after cytotoxic chemotherapy in cancer patients: assessment of treatment efficacy; rating of drug side-effects; and detection of relapse. Routine controls can only be efficiently performed with a thorough knowledge of the biology of the tumor and of the therapeutic efficacy of the available cytotoxic drugs. The frequency and type of follow-up examinations depend mainly on the curative or palliative treatment potential. Examples of superfluous controls are mentioned. By prevention of unnecessary examinations the primary care physician could play an important role in cut down of health care costs.