Digitally Supported Prehabilitation Before Major Visceral Cancer Surgery

Major visceral oncologic surgery remains one of the most physiologically demanding therapeutic interventions in modern cancer care. Patients undergoing surgery of the pancreas, liver, bile ducts, stomach, or esophagus frequently present with reduced physical reserve, impaired nutritional status, sarcopenia, cancer-related fatigue, reduced exercise tolerance, psychological distress, and multiple comorbidities. These factors contribute substantially to postoperative morbidity, prolonged recovery, delayed rehabilitation, reduced quality of life, and increased health care utilization. Despite advances in surgical and perioperative care, postoperative complications remain common after major visceral oncologic surgery. Functional decline following surgery may additionally impair the initiation or completion of adjuvant oncologic therapies, potentially affecting long-term prognosis. Therefore, strategies that optimize patients before surgery and support continuity of recovery throughout the perioperative pathway are increasingly recognized as clinically relevant. Prehabilitation aims to improve the physiological and psychological readiness of patients before surgery through targeted interventions, commonly including exercise training, nutritional optimisation, psychological support, and health education. Previous studies have shown that prehabilitation may improve functional capacity and may contribute to improved postoperative recovery. However, important gaps remain regarding implementation feasibility, integration into routine clinical care, long-term continuity between prehabilitation and rehabilitation, and the role of digital technologies in supporting patient engagement and adherence. In Austria, structured prehabilitation pathways are currently not routinely implemented for patients undergoing major visceral oncologic surgery. Furthermore, perioperative care pathways often remain fragmented, particularly during the transition from surgical hospitalization to rehabilitation. Digital technologies have the potential to improve continuity of care, facilitate communication, support self-management, and improve adherence to exercise and rehabilitation programs. Nevertheless, the feasibility and acceptance of digitally supported perioperative pathways in this patient population remain insufficiently investigated. The Prehab2Rehab-OncoVis study was therefore developed to evaluate the feasibility, safety, acceptability, and implementation characteristics of a multimodal digitally supported prehabilitation pathway extending from preoperative preparation through rehabilitation and follow-up. The study additionally aims to generate preliminary clinical and functional outcome data that may support the planning of future randomized controlled trials. The study is conducted at the University Hospital Salzburg and the University Institute of Sports Medicine, Prevention and Rehabilitation in cooperation with the Ludwig Boltzmann Institute for Rehabilitation Research and the Ludwig Boltzmann Institute for Digital Health and Prevention within the framework of the Prehab2Rehab consortium. The study is designed as a prospective single-arm feasibility cohort study. Approximately 30 adult patients scheduled for major visceral oncologic surgery with curative intent will be consecutively recruited, with the possibility of including up to 50 participants if feasible within the recruitment period. Historical comparison cohorts will additionally be used to contextualize observed outcomes. These include a local hospital cohort of patients who previously underwent similar surgery without prehabilitation and a national rehabilitation cohort derived from routine rehabilitation datasets matched for diagnosis, sex, and age. The primary objective of the study is to evaluate feasibility outcomes associated with the implementation of the digitally supported multimodal prehabilitation intervention. Feasibility outcomes include recruitment rate, retention rate, communication with participants, data collection and data management performance, adherence to the intervention, intervention fidelity, safety, and acceptability of the digital technologies. Recruitment feasibility will be evaluated by documenting the proportion of eligible patients who provide written informed consent for study participation. Retention feasibility will be assessed by determining the proportion of enrolled participants who complete the intervention and study assessments. Intervention adherence will be assessed through attendance at supervised sessions, completion of prescribed activities, and use of the digital tools. Fidelity will evaluate the degree to which the intervention is implemented according to the planned protocol and standardized procedures. Acceptability and usability of the digital tools will be evaluated using validated questionnaires, including the Unified Theory of Acceptance and Use of Technology 2 (UTAUT-2), the mHealth App Usability Questionnaire (MAUQ), the Mobile Application Rating Scale (MARS), AttrakDiff, and the Affinity for Technology Interaction (ATI) questionnaire. In addition, qualitative participant experiences will be explored through semi-structured interviews performed after completion of the intervention pathway. The intervention consists of a multimodal prehabilitation program combining supervised exercise training, nutritional counseling, psycho-oncological distress screening, promotion of health literacy, and digitally supported patient engagement. The exercise intervention follows a structured multimodal approach and is individualized according to medical evaluation, baseline functional capacity, and therapist judgment. The intervention is delivered in two formats depending on travel distance and feasibility. Participants living within practical traveling distance of the training center participate in a standard center-based exercise program consisting of three supervised exercise sessions per week at the University Institute of Sports Medicine, Prevention and Rehabilitation. Participants with travel times exceeding approximately 40 minutes one way may participate in a hybrid model consisting of one supervised center-based session and two remotely supervised tele-prehabilitation sessions per week. Exercise sessions are structured according to the Frequency, Intensity, Time, and Type (FITT) principles and include warm-up, endurance training, resistance training, and cool-down phases. Endurance exercise is primarily performed on stationary cycle ergometers at moderate intensity. Resistance exercise includes machine-based or elastic-band-based exercises targeting major muscle groups. Exercise intensity and progression are adapted individually according to baseline assessment, perceived exertion, and clinical status. During supervised endurance exercise sessions, patient safety is ensured through clinical supervision by exercise therapists and physicians. Electrocardiographic monitoring may be used when clinically indicated. Emergency procedures and emergency equipment are available during all center-based sessions. The hybrid tele-prehabilitation sessions are conducted using the CAATS telecommunication platform. During remote sessions, participants receive live visual supervision from the therapist. If adequate visual supervision cannot be established, the tele-prehabilitation session is not conducted. The tele-prehabilitation format was developed to improve feasibility and accessibility for participants living farther away from the training center while maintaining structured supervision and continuity. Participants are additionally encouraged to maintain an active lifestyle outside supervised sessions. Home-based physical activity recommendations include regular walking and low-to-moderate intensity activities integrated into daily life. Physical activity guidance is progressively adapted across the intervention period. Nutritional counseling is performed in parallel with the exercise intervention and follows current European Society for Clinical Nutrition and Metabolism (ESPEN) recommendations for clinical nutrition in surgery. Nutritional screening includes assessment using the Nutritional Risk Screening 2002 score (NRS-2002). Individualized counseling aims to optimize preoperative nutritional status and ensure adequate caloric and protein intake. When clinically indicated, oral nutritional supplementation may be recommended. Nutritional counseling is primarily delivered through face-to-face consultations but may additionally be supported through teleconsultation using the CAATS platform. Psycho-oncological distress screening is integrated into the intervention pathway in accordance with recommendations of the German Cancer Society and psycho-oncological guidelines. Screening includes use of the National Comprehensive Cancer Network (NCCN) Distress Thermometer and the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30). Participants exceeding predefined thresholds or requesting support may be referred for psycho-oncological counseling and supportive care according to standard clinical pathways. Health literacy promotion represents an additional core component of the intervention. Health literacy is evaluated using the European Health Literacy Questionnaire (HLS-EU-Q) and the Brief Health Literacy Screening Tool (BRIEF). Educational support is provided using the HERO application. The HERO application was developed to provide structured evidence-based information throughout the perioperative pathway. The application includes educational material regarding disease-related information, surgery, rehabilitation, physical activity, recovery processes, and patient orientation. The HERO application serves exclusively as an educational and motivational support tool and is not intended as a diagnostic or therapeutic medical device. The aktivplan application is used as a digital exercise planner and training diary. It allows participants to access prescribed exercise sessions, document completed activities, receive reminders, and maintain an overview of their training schedule. The application additionally supports adherence monitoring and allows the study team to evaluate engagement and implementation fidelity. Together, HERO, aktivplan, and CAATS form an integrated digital support environment intended to facilitate continuity between prehabilitation, surgery, transition, rehabilitation, and recovery. The perioperative pathway assessed within the study includes multiple predefined phases and assessment time points. Baseline assessments are performed at the start of prehabilitation (Prehabilitation Assessment 1 \[PRE1\]). Repeat assessments are conducted after completion of the prehabilitation intervention but before surgery (Prehabilitation Assessment 2 \[PRE2\]). Surgical hospitalization and postoperative recovery are subsequently documented. Rehabilitation-related assessments are performed at admission to rehabilitation (Rehabilitation Assessment 1 \[REH1\]) and at discharge from rehabilitation (Rehabilitation Assessment 2 \[REH2\]). A final follow-up assessment is conducted approximately three months after surgery. The rehabilitation phase itself is conducted as usual care without modification of standard rehabilitation procedures. However, participants who undergo rehabilitation at the affiliated rehabilitation center are systematically followed to evaluate rehabilitation outcomes and user experiences across the complete treatment pathway. Secondary outcomes are exploratory and intended to provide preliminary information regarding potential effects of the intervention on clinical, functional, physiological, and patient-reported outcomes. Clinical recovery indicators include time to functional recovery, postoperative complications, Comprehensive Complication Index, length of intensive care unit stay, length of hospital stay, readmission rates, and short-term mortality. Postoperative complications are documented according to the Clavien-Dindo classification. Functional independence and activity-related outcomes include the Barthel Index, Eastern Cooperative Oncology Group Performance Status, Rapid Assessment of Physical Activity, and Exercise Self-Efficacy Scale. Psychological well-being and quality of life are assessed using the Patient Health Questionnaire-4 (PHQ-4), Hospital Anxiety and Depression Scale (HADS), EuroQol-5 Dimensions-5 Levels questionnaire (EQ-5D-5L), NCCN Distress Thermometer, and the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). Broader rehabilitation-related and vocational aspects are additionally explored using the International Classification of Functioning, Disability and Health framework and the Screening Instrument for Medical-Vocational Oriented Measures Clinical Version (SIMBO-C). The study additionally includes exploratory assessments related to patient blood management and metabolic control. Patient blood management procedures follow current Austrian, European, and international recommendations. Routine laboratory assessments include hemoglobin concentration, ferritin, transferrin saturation, and related hematological parameters. These measurements are intended for scientific characterization and are not used for clinical treatment decisions. Metabolic assessments include fasting glucose and glycated hemoglobin (HbA1c) measurements. Participants with abnormal glucose metabolism may receive additional counseling and optimization according to routine clinical practice. Functional and physiological assessments are additionally performed to characterize changes in physical capacity throughout the perioperative pathway. Anthropometric measurements include body mass, body height, and body mass index. Body composition is assessed using bioelectrical impedance analysis to estimate lean mass, fat mass, and phase angle. Cardiorespiratory fitness is evaluated using cardiopulmonary exercise testing performed on an electronically braked cycle ergometer. Measures include peak oxygen uptake and maximal mechanical work capacity. Continuous electrocardiographic monitoring and standardized safety procedures are used during testing. Functional exercise capacity is evaluated using the Six-Minute Walk Test and the Timed Up and Go test. Muscle strength is evaluated using standardized handgrip dynamometry procedures. The study additionally incorporates qualitative evaluation methods. Semi-structured interviews are performed with a subset of participants to explore user experiences, perceived barriers, facilitators of participation, and perceptions regarding the digital support pathway. Interviews are audio-recorded with participant consent, transcribed, pseudonymized, and analyzed qualitatively. All participant data are pseudonymized at the time of collection. A separate identification log linking participant identity to study identifiers is stored securely with restricted access. Data handling procedures comply with the European General Data Protection Regulation (GDPR) and institutional data protection requirements. The study is conducted in accordance with the Declaration of Helsinki and principles of Good Clinical Practice (GCP). Ethical approval was obtained from the responsible ethics committee before participant recruitment. All participants provide written informed consent before participation in any study-related procedures. Safety monitoring includes systematic documentation of adverse events and serious adverse events occurring during the study period. Exercise-related safety is ensured through supervised training, standardized emergency procedures, and predefined stopping criteria. Serious adverse events related or potentially related to study procedures are reported according to institutional and regulatory requirements. Statistical analyses primarily focus on feasibility and implementation outcomes. Descriptive statistics are used to summarize recruitment, retention, adherence, acceptability, usability, and safety data. Exploratory analyses may additionally evaluate changes in clinical and functional outcomes over time and contextual comparisons with historical cohorts. The study is not powered to provide definitive conclusions regarding intervention efficacy. The results of the study are intended to provide important feasibility and implementation data regarding the integration of digitally supported prehabilitation pathways into perioperative care for patients undergoing major visceral oncologic surgery. Findings from this study may support the design of future larger randomized controlled trials and contribute to the development of integrated perioperative care pathways connecting prehabilitation, surgery, rehabilitation, and digital health support.