<p>Following surgery, radiotherapy and systemic therapy, rehabilitation represents the fourth pillar of cancer treatment, even though it is often not perceived as such. Rehabilitation supports cancer patients in returning to everyday or professional life, often serving as a&#xa0;so-called teachable moment for crucial lifestyle changes and marking the beginning of cancer survivorship. Rehabilitation is oriented towards the goals and resources of cancer patients and is therefore a&#xa0;prime example of personalized medicine. It operates according to the so-called biopsychosocial model defined by the World Health Organization, which is based on the International Classification of Functioning. The aim is to enable rehabilitants to participate in social or professional life again, taking into account all personal and environmental factors, by improving functional impairments and limitations caused by the tumour disease and its treatment. This is achieved through an individually designed, usually 21-day, multimodal rehabilitation programme. The therapeutic plan includes individual and group therapy; nutritional, psychological and social (legal) counselling; and sports and exercise therapy. Educational and manual therapeutic elements are also included. At the beginning, 3–5&#xa0;therapy goals are formulated together with the rehabilitants, and their achievement is reviewed at the end. To further evaluate the effectiveness of the rehabilitation measure, tests of physical performance, screenings, and patient-reported outcome measurements assessing (long-term) therapeutic effects and health-related quality of life at the start and end of the programme can serve as helpful instruments.</p>