The indication for complementary psychotherapy in cancer patients must be considered when the stresses of the disease and its treatment are more than the patient's reserves can cope with. The aims of psycho-oncological treatment include improvement of the patient's quality of life, management of comorbid psychological disorders, optimization of the patient's ability to cope, the provision of social support, the overcoming of feelings of helplessness and hopelessness, conflict- and focus-oriented stabilization, and prolongation of life. Since available psycho-oncological resources continue to be extremely thin on the ground, sound concepts must be developed with the aim of achieving a link-up of psycho-oncological resources with oncological services.