Cancer patients require chronic management and care. For those individuals living with cancer, a comprehensive approach that acknowledges the interdisciplinary nature of their condition can help guide appropriate care strategies and support their overall well-being. Approximately 45% of patients diagnosed with cancer undergo surgery to remove their tumor. Despite the advancements in surgical techniques, anesthesia, and perioperative care, major cancer surgeries still pose a significant challenge leading to a considerable decline in physiological and functional capacity. Traditionally, efforts focused on postoperative rehabilitation to enhance recovery. Recently, prehabilitation, a form of rehabilitation which aims to improve functional capacity before surgery, has gained attention for its potential benefits in improving surgical outcomes. However, prehabilitation lacks objective assessment measures to evaluate its effectiveness. Developing validated outcome measures is essential to enhance the impact of prehabilitation on surgical outcomes and long-term care for cancer patients. Heart rate variability (HRV) is a physiological parameter that measures the variation in time intervals between consecutive heartbeats, reflecting the autonomic nervous system activity which might serve as a valuable solution for objective outcome measures in evaluating the effectiveness of prehabilitation for cancer patients, providing an objective tool to assess and monitor physiological response to stress, recovery capacity, and autonomic nervous system activity. A multicenter randomized controlled trial will be conducted to assess the impact of a multimodal prehabilitation program on HRV. Patients aged 18 or older, scheduled for elective major cancer surgery will be randomized to receive either prehabilitation or standard care. The prehabilitation arm will receive a program involving home-based physical, nutritional, and psychological interventions for at least four weeks. Participants allocated to the control group will receive usual care. Patients will be followed throughout the study using an innovative mobile application, allowing for real-time monitoring and data collection during the prehabilitation program. The study has two primary outcomes: A) to assess the impact of prehabilitation on increasing preoperative HRV in chronic cancer patients undergoing surgery; B) to assess the effect of prehabilitation on length of hospital stay.

Cancer patients require long-term management and ongoing care due to the chronic nature of their condition. Major cancer surgeries pose significant challenges, resulting in a decline in physiological and functional capacity. Traditionally, postoperative rehabilitation has been the most suitable intervention to improve functional recovery. Prehabilitation, which aims to enhance patients' functional capacity before surgery and to improve patients' ability to cope with physiological stress, is considered the best form of rehabilitation. Through multimodal strategies like exercise, nutrition and psychological support, prehabilitation can improve surgical outcomes for cancer patients. However, prehabilitation lacks objective assessment measures. Heart rate variability (HRV), a physiological parameter measuring variation in heartbeats, reflects autonomic nervous system activity and an increase in HRV is associated with fitness and recovery capacity in sports medicine. Psychological factors, nutritional status and physical exercise influence HRV. Hence, HRV could be used to objectively assess prehabilitation interventions. In addition, HRV is widely used in risk assessment in cardiology, and a reduction in HRV is recognized to be associated with complications and mortality. Despite its evident potential in risk assessment, HRV has never been utilized in preoperative assessments.

This is an international, multicenter, parallel-group, randomized study in chronic cancer patients undergoing surgery. Adult men and women patients who are eligible according to the inclusion/exclusion criteria will be randomized to study the effect of prehabilitation versus standard care on heart rate variability (HRV).

A total of 600 patients will be recruited by systematic screening of patients scheduled for elective surgical procedures. All patients undergoing major cancer surgery will be screened for eligibility and those who meet the inclusion/exclusion criteria will be approached for consent. Research personnel will use a web-based randomization system to assign patients (1:1 ratio) to either the prehabilitation or control arm. Study personnel will also collect data on recruitment rates, with reasons for non-enrollment.

Eligible patients will be randomly assigned to one of two treatments:

1. Multimodal prehabilitation program for four weeks starting as soon as possible before surgery;
2. Standard care.

The multimodal prehabilitation program will be individualized by carefully integrating and adapting various components to meet individual needs. The program will last four weeks (plus maintenance in case of delayed surgery), and will incorporate exercise training, nutritional therapy, and anxiety reduction techniques. After enrollment, patients will receive initial contact from trained personnel through telemedicine. To ensure personalized care, a comprehensive assessment will be conducted to identify specific physical, nutritional, or psychological challenges. Based on this assessment, a customized intervention plan will be prescribed to achieve tailored exercise training, optimized nutrition, and effective distress-coping strategies. Patients will be requested to download a dedicated smartphone application, which will comprehensively monitor and track their progress towards achieving their prehabilitation goals. After completing the four-week program, patients will continue a maintenance program until surgery.

The first HRV measurement will be performed for 5 minutes in an isolated room, after signing the written consent and before randomization, on the day of screening which occurs several weeks before surgery. The second HRV measurement will be performed the day before surgery. Both HRV time-domain measurements and HRV frequency-domain measurements will be evaluated.

Inclusion Criteria:

1. Scheduled to undergo elective major abdominal or thoracic cancer surgery;
2. Scheduled to undergo surgery at least three weeks after enrollment;
3. Age ≥ 18 years;
4. Provide written informed consent;
5. Willing and able to use smartphone application.

Exclusion Criteria:

1. Presenting with very poor functional capacity;
2. American Society of Anesthesiologists (ASA) physical status classes 5-6;
3. Disabling orthopedic, neuromuscular, and psychiatric diseases or other conditions that preclude participation in a prehabilitation program.