Because of the increasing global cancer burden and the WHO epidemiological estimation in terms of number of new cases, deaths and long-survivors worldwide, an interdisciplinary approach, including psychiatric and psychoncology care is mandatory in oncology. About 50% of cancer patients have in fact been shown to have psychiatric disorders, including clinically significant emotional distress and/or unrecognised or untreated psychosocial conditions as a consequence of cancer at some point during the cancer trajectory. These problems are associated with the patient's reduction of quality of life, impairment in social relationships, longer rehabilitation time, poor adherence to treatment and abnormal illness behaviour. Because of these reasons, the internationally recognised IPOS Standards of Quality Cancer Care underline that psychosocial cancer care should be recognised as a universal human right; that quality cancer care must integrate the psychosocial domain into routine care and that distress should be measured as the sixth vital sign after temperature, blood pressure, pulse, respiratory rate and pain. In spite of social inequalities still existing between countries in the organisation and implementation of psychosocial oncology, recommendations and guidelines are available regarding screening, assessment and intervention to psychiatric and psychosocial disorders across the trajectory of cancer. The clinical and political agenda of psychoncology as a mandatory component of a whole comprehensive person-centred approach to cancer should therefore be acknowledged in psychiatry.