LAUSR

The demands placed on surgical systems nowadays are greater than ever. The population undergoing major abdominal surgery is becoming older and increasingly frail with multiple co-morbidities1. Many are obese and physically unfit. These patient challenges are compounded by organizational issues, such as the drive for early postoperative discharge coupled with pressure to reduce readmission rates. At a professional level, surgeons face increasing scrutiny of their work in response to governmental and public demands for greater transparency. The high-risk surgical patient is at greater risk of adverse postoperative events and prolonged recovery2. Patients with cancer pose specific challenges, including weight loss, fatigue, malnutrition and anaemia, that influence surgical outcome. The addition of neoadjuvant therapies might provide a survival benefit, but often at a cost to functional capacity when it is most needed. Recent improvements in postoperative outcomes can be attributed to the centralization of cancer surgery, the introduction of minimally invasive surgical techniques, and the design and delivery of perioperative care programmes. Nevertheless, challenges remain and many procedures are associated with high rates of postoperative morbidity and prolonged hospital stay2. Enhanced recovery protocols (ERPs) are well established in many surgical specialties and have led to a measurable improvement in postoperative outcomes3. Most ERP elements are focused, however, on the intraoperative and postoperative phases of the hospital stay. Prehabilitation is based on the principle that structured exercise in the preoperative period provides patients with a ‘physiological buffer’ to withstand the stress of surgery. This could potentially lead to reduced postoperative complications and minimize functional decline following surgery4. The benefit of structured exercise within healthcare is well recognized. It has been associated with lower healthcare utilization in a range of medical conditions and has contributed to improved patient-reported outcomes5. In the context of major abdominal surgery, structured exercise is associated with improved preoperative functional capacity, but with limited evidence that it contributes to improved outcomes6. There are a number of prehabilitation trials in progress (www.nhs.uk/ Conditions/Clinical-trials) designed to address the evidence gap, but these may be limited by the unimodal approach where the focus is predominantly on exercise. There is relatively little acknowledgement of the holistic approach required to deliver prehabilitation successfully7. Future research trials should incorporate the findings from other healthcare disciplines if robust evidence in support of prehabilitation is to be provided. Exercise, when prescribed in a healthcare setting, is considered a complex intervention. Adoption and adherence to exercise are determined by behavioural, physiological, psychological, environmental and social factors8. Understanding and addressing the impact that these factors have on adherence to exercise is critical to the success of timelimited exercise programmes such as prehabilitation. Exercise programmes have greater benefit if they include principles of behaviour change. For example, self-efficacy is the reflection of one’s confidence and capacity to undertake changes that are likely to contribute to achieving the desired outcomes. It has been identified as an important mediator of exercise behaviour in other healthcare settings, and is an important predictor of adherence to exercise9. Self-efficacy, as measured by validated tools, is an outcome of the success of exercise programmes. It is a modifiable construct, and strategies to improve it lead to greater success with exercise adherence. Self-efficacy interventions include achievement of personalized goals, vicarious experience, verbal feedback and encouragement. These not only improve adoption and adherence to exercise, but also provide patients with the ability to self-monitor10 and adapt their exercise programme to changing clinical conditions. This is especially relevant for patients receiving neoadjuvant therapies. Intervention fidelity, the extent to which an intervention was delivered as planned, is a critical aspect of trial design and evaluation. The lack of robust evidence of the impact of prehabilitation on improved postoperative outcomes6 is possibly a result of patients in the ‘intervention’ arm not being adherent to the prescribed exercises4. Many prehabilitation programmes are delivered within a hospital setting, but delivering