Mobile health intervention CanRelax reduces distress in people with cancer in a randomized controlled trial

Jürgen Barth^#¹, Sonja Schläpfer^#², Fabian Schneider³, Prabhakaran Santhanam⁴, Tobias Kowatsch^{5

6

7}, Priska Heinz⁸, Ulrike Held⁸, Manuela Eicher^{9

10}, Claudia M Witt^{2

11}

Affiliations

¹ Institute for Complementary and Integrative Medicine, University Hospital Zurich and University of Zurich, Zurich, Switzerland. mail@juergen-barth.de.
² Institute for Complementary and Integrative Medicine, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
³ Byldr GmbH, Schlieren, Switzerland.
⁴ Datahouse AG, Zurich, Switzerland.
⁵ Centre for Digital Health Interventions, Department of Management, Technology, and Economics, ETH Zurich, Zurich, Switzerland.
⁶ Institute for Implementation Science in Health Care, University of Zurich, Zurich, Switzerland.
⁷ School of Medicine, University of St. Gallen, St. Gallen, Switzerland.
⁸ Department of Biostatistics at the Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland.
⁹ IUFRS Institute of Higher Education and Research in Healthcare, Faculty of Biology and Medicine, University of Lausanne and Lausanne University Hospital, Lausanne, Switzerland.
¹⁰ Department of Oncology, Lausanne University Hospital, Lausanne, Switzerland.
¹¹ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

^# Contributed equally.

PMID: 40348854
PMCID: PMC12065826
DOI: 10.1038/s41746-025-01688-x

Mobile health intervention CanRelax reduces distress in people with cancer in a randomized controlled trial

Jürgen Barth et al. NPJ Digit Med. 2025.

. 2025 May 10;8(1):269.

doi: 10.1038/s41746-025-01688-x.

Authors

Jürgen Barth^#¹, Sonja Schläpfer^#², Fabian Schneider³, Prabhakaran Santhanam⁴, Tobias Kowatsch^{5

6

7}, Priska Heinz⁸, Ulrike Held⁸, Manuela Eicher^{9

10}, Claudia M Witt^{2

11}

Affiliations

¹ Institute for Complementary and Integrative Medicine, University Hospital Zurich and University of Zurich, Zurich, Switzerland. mail@juergen-barth.de.
² Institute for Complementary and Integrative Medicine, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
³ Byldr GmbH, Schlieren, Switzerland.
⁴ Datahouse AG, Zurich, Switzerland.
⁵ Centre for Digital Health Interventions, Department of Management, Technology, and Economics, ETH Zurich, Zurich, Switzerland.
⁶ Institute for Implementation Science in Health Care, University of Zurich, Zurich, Switzerland.
⁷ School of Medicine, University of St. Gallen, St. Gallen, Switzerland.
⁸ Department of Biostatistics at the Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland.
⁹ IUFRS Institute of Higher Education and Research in Healthcare, Faculty of Biology and Medicine, University of Lausanne and Lausanne University Hospital, Lausanne, Switzerland.
¹⁰ Department of Oncology, Lausanne University Hospital, Lausanne, Switzerland.
¹¹ Institute of Social Medicine, Epidemiology and Health Economics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

^# Contributed equally.

PMID: 40348854
PMCID: PMC12065826
DOI: 10.1038/s41746-025-01688-x

Abstract

Mindfulness and relaxation exercises are effective face-to-face interventions for reducing distress in people with cancer. Their effectiveness in mobile health settings has yet to be investigated. This study evaluated the effectiveness of the CanRelax 2 app in reducing distress in people with cancer. German-speaking adults diagnosed with cancer within the last five years with elevated distress levels (Distress Thermometer ≥5) were recruited. Participants were randomized to the CanRelax 2 app or a waitlist control group. The primary endpoint was the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS) after 10 weeks (210 participants). We observed a clinically meaningful larger reduction in PHQ-ADS scores in the intervention group compared to the control group (-3.7, 95%-CI from -5.7 to -1.6; p = 0.0005). Similar effects were found for distress, well-being, and self-regulation. Our results confirm the effectiveness of a mobile health app in reducing distress in people with cancer. Registration: German Clinical Trials Register (DRKS00027546) on 23.02.2022.

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Conflict of interest statement

Competing interests: C.M.W. has active research grants to the University for digital health projects from the DIZH, the Swiss Cancer Research foundation, the German health care Innovation Fund, and Newsense Lab GmbH and has received honoraria from Swiss hospitals for scientific presentations on the digitalization and AI in medicine. F.S. is founder of Byldr, which is company for developing mobile health solutions. During the development of CanRelax 2, T.K., F.S., and P.S. were developers and promoters of the open-source software platform MobileCoach. T.K. and P.S. are affiliated with the Centre for Digital Health Interventions (CDHI), a joint initiative of the Institute for Implementation Science in Health Care, University of Zurich, the Department of Management, Technology, and Economics at ETH Zurich, and the Institute of Technology Management and School of Medicine at the University of St.Gallen. C.D.H.I. is funded in part by CSS, a Swiss health insurer, MTIP, a Swiss digital health investor company, and Mavie Next, an Austrian health provider. T.K. was also a co-founder of Pathmate Technologies, a University spin-off company that creates and delivers digital clinical pathways. However, Pathmate Technologies, CSS, MTIP, and Mavie Next were not involved in this research. J.B. received honoraria for workshops on digital health. M.E. received institutional research grants from Kaiku Health and reports grants from Bristol Myers Squibb, Roche and institutional fees as a Scientific Advisory Board Member/Consultant from Roche, outside the submitted work. The remaining authors have no conflicts of interest to declare.

Figures

**Fig. 1. Flow chart from download to data analysis.**
This figure presents a CONSORT diagram detailing the participant flow through the CanRelax trial. It includes numbers from the download, eligibility check, randomization and data analysis. Participants were included from 20.07.2022 to 16.02.2023 (asterisk). People with low distress were excluded from the CanRelax trial but received the app intervention (double asterisk).

**Fig. 2. CanRelax 2 app group compared with waitlist control (primary endpoint PHQ-ADS) before and after 10 weeks.**
Main analysis of the primary endpoint PHQ-ADS after 10 weeks. Results are from a linear model (ANCOVA) with treatment as fixed effect and adjusted for sex and baseline distress (PHQ-ADS).

**Fig. 3. Course of secondary outcomes (baseline to week 10).**
The four Figures show four different outcomes of the CanRelax trial. a DT: Distress Thermometer; (b) PHQ-4: Patient Health Questionnaire 4; (c) WHO-5: World Health Organization-Five Well-Being Index; (d) MAIA: Multidimensional Assessment of Interoceptive Awareness (subscale self-regulation). Dashed lines indicate the mean measurements across time points. Results are based on a linear mixed effects model with treatment group (fixed effect), sex (fixed effect), and random intercept and slope for each participant.

See this image and copyright information in PMC

References

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Mobile health intervention CanRelax reduces distress in people with cancer in a randomized controlled trial

Affiliations

Mobile health intervention CanRelax reduces distress in people with cancer in a randomized controlled trial

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References

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