This review summarises the current knowledge of exercise training, which is increasingly used to rehabilitate patients with cancer after anti-cancer treatment, aiming to manage acute and long-term side effects and physical limitations. However, exercise training may also play a critical role in the early preoperative management of patients with cancer. In this period, preoperative exercise training may ensure, that patients reach the curative tumour resection by preventing tumour progression, reducing complications to neoadjuvant treatment and lessening physical deterioration, all leading to improved surgical outcome and enhanced long-term survival. †) Pernille Højman died 6 April 2019, after she had written a major part of the script.