Prospektive Beobachtungsstudie zum Zusammenhang zwischen der täglichen Schrittzahl und dem Ansprechen auf die Behandlung bei Patienten mit Rektumkarzinom (STEP-R)

Background and Rationale Rectal cancer treatment includes a multimodal approach, often involving total neoadjuvant therapy (TNT), which combines chemotherapy and radiotherapy before surgical intervention. While physical activity, particularly walking, has shown general health benefits for cancer patients, the specific effects of objectively measured daily activity on treatment outcomes, such as response rates and side effect incidence, remain insufficient. Current methods for assessing physical activity largely rely on self-reported data, which can be less accurate. This study uses wearable technology (Huawei Watch Fit 2 smartwatches) to gather objective, real-time data on patients' physical activity, offering a novel approach to tracking exercise and health metrics throughout cancer treatment.

Study Objectives Primary Objective: To determine whether higher physical activity levels, specifically daily step counts, are associated with increased complete pathological response rates in rectal cancer patients undergoing TNT.

Secondary Objectives:

To evaluate the relationship between physical activity (step count) and the frequency and severity of treatment-related side effects.

To assess changes in sleep quality and heart rate as additional metrics of physical well-being and their potential influence on treatment tolerance and outcomes.

Methodology Participants: This study will include approximately 200 patients diagnosed with locally advanced rectal cancer and scheduled to begin TNT. Eligibility criteria focus on patients who can safely undergo physical activity monitoring and do not have contraindications for wearable device use.

Data Collection with Smartwatches:

Physical Activity: The smartwatch will track daily step counts and duration of physical activity that elevates the heart rate by at least 20% above the basal level.

Heart Rate Monitoring: Continuous heart rate data will be recorded to observe variability and detect any correlations with activity and side effect tolerance.

Sleep Quality: Sleep patterns and quality will be recorded to assess rest as a potential factor affecting treatment response.

Questionnaires: Two validated questionnaires will be administered:

EORTC QLQ-C30 (to assess cancer-related quality of life) and Pittsburgh Sleep Quality Index (to assess sleep quality and disturbances). Intervention and Monitoring Plan Weekly Monitoring: Patients will be seen weekly as part of their standard treatment schedule. During these visits, data from the smartwatch app (step count, heart rate, and sleep quality) will be reviewed alongside any updates on treatment side effects.

Duration and Follow-Up: Each participant will be followed from the initiation of TNT until surgical intervention (approximately 4-6 months). Data collection and follow-up are expected to span a total of 12-15 months for comprehensive data gathering across all enrolled patients.

Anticipated Outcomes and Significance This study aims to enhance understanding of physical activity's role in cancer treatment. By leveraging wearable technology to gather objective data, the study seeks to establish whether physical activity metrics correlate with treatment efficacy and side effect profiles. If successful, the findings could support integrating exercise recommendations into routine oncology care, tailored to individual patient metrics.

Future Directions Pending study outcomes, further research could focus on expanded trials in diverse cancer types, potentially using smartwatches to guide individualized exercise protocols, adjust treatment regimens, and support patient education on activity benefits during cancer therapy.