This study examines whether a home-based telephone-guided preoperative exercise programme is feasible and effective in improving cardiorespiratory fitness in patients with colorectal cancer who are high risk due to their existing co-morbidity.

Preoperative exercise, also know as prehabilitation, has been shown to improve physical fitness and potentially reduce postoperative complications in patients undergoing surgery. Patients are often labelled high risk for surgery due to their existing ill-health e.g. heart and lung disease. High risk patients comprise approximately 12% of all elective cancer cases, but account for 80% of all post-operative mortality. Complications significantly affect the quality of life of each CRC patient, both in the short and long-term, and can also impact on survival. It is critical that patients who are deemed at high risk of complications are optimised in the preoperative period. Exercise in the period before surgery is therefore one potential method of improving high risk patients' physical fitness levels while potentially reducing their risk of postoperative complications and subsequent mortality.

Inclusion Criteria:

• Primary operable colorectal cancer;
• Awaiting surgery with curative intent;
• Deemed high risk by the responsible clinical team;
• Ability to mobilise independently

Exclusion Criteria:

• Patients with primary or recurrent inoperable colorectal cancer.
• Patients undergoing preoperative chemo- and/or radiotherapy.
• Patients who decline or are deemed unfit for operative management.
• Patients who lack capacity to consent.