This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Formative Research, is properly cited. The complete bibliographic information, a link to the original publication on https://formative.jmir.org, as well as this copyright and license information must be included.
Increasing evidence shows that lifestyle interventions can improve the symptoms, quality of life (QoL), and even overall survival of patients with cancer. Digital therapeutics (DTx) can help implement behavioral modifications and empower patients through education, lifestyle support, and remote symptom monitoring.
We aimed to test the feasibility of a DTx program for patients with cancer, as measured by engagement, retention, and acceptability. In addition, we explored the effects of the program on cancer-related QoL.
We conducted a 4-week single-arm trial in Iceland, where DTx was delivered through a smartphone app. The intervention consisted of patient education about mindfulness, sleep, stress, and nutrition; lifestyle coaching; and the completion of daily missions for tracking physical activity and exercise, reporting patient-reported outcomes (PROs), practicing mindfulness, and logging healthy food intake. Information on program engagement and retention, step goal attainment, as well as PROs were collected throughout the study. QoL was measured using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 at baseline and follow-up.
In total, 30 patients with cancer undergoing active therapy were enrolled, and 29 registered in the app (23 female, 18 with breast cancer; mean age 52.6, SD 11.5 years). Overall, 97% (28/29) of participants were active in 3 of the 4 weeks and completed the pre- and postprogram questionnaires. The weekly active days (median) were 6.8 (IQR 5.8-6.8), and 72% (21/29) of participants were active at least 5 days a week. Users interacted with the app on average 7.7 (SD 1.9) times per day. On week 1, all 29 participants used the step counter and logged an average of 20,306 steps; 21 (72%) participants reached their step goals of at least 3000 steps per day. On week 4, of the 28 active users, 27 (96%) were still logging their steps, with 19 (68%) reaching their step goals. Of the 28 participants who completed the satisfaction questionnaire, 25 (89%) were likely to recommend the program, 23 (82%) said the program helped them deal with the disease, and 24 (86%) said it helped them remember their medication. QoL assessment showed that the average global health status, functioning, and symptom burden remained stable from baseline to follow-up. In all, 50% (14/28) of participants reported less pain, and the average pain score decreased from 31 (SD 20.1) to 22.6 (SD 23.2;
The high retention, engagement, and acceptability found in this study demonstrate that multidisciplinary DTx is feasible for patients with cancer. A longer, full-scale randomized controlled trial is currently being planned to evaluate the efficacy of the intervention.
According to the latest statistics, the global prevalence of all types of cancers is projected to increase by nearly 50% in the next 20 years, with female breast cancer being the most prevalent in 2020 [
Research over the last 2 decades has shown that lifestyle modifications can effectively improve the quality of life (QoL) of patients with cancer. Mindfulness exercises, muscle relaxation, and cognitive behavioral therapy can help patients cope with stress [
The advent of digital technology and the wide reach of smartphones provide a potential avenue for motivating and delivering structured lifestyle programs for patients. Several digital intervention programs have been developed for patients with cancer and cancer survivors to provide psychological support and help manage symptoms [
The primary aim of this study was to assess the feasibility of a holistic DTx program to improve the lifestyle and health-related QoL of patients in active anticancer therapy. This was measured in terms of user engagement, retention, acceptability, and step goal attainment. An additional objective of the study was to gather preliminary indications of the program’s efficacy through secondary endpoint measures. The results of this feasibility trial will be used to inform a future definitive randomized controlled trial (RCT).
We conducted a 4-week single-arm trial from August to November 2021 at the Ljósið cancer rehabilitation clinic in Iceland. Patients were invited to participate in the study, which was promoted as a support program aimed at improving QoL for patients with cancer, via emails and educational lectures at the clinic, and they were recruited after voluntarily reaching out. Inclusion criteria were (1) diagnosed with cancer and receiving anticancer treatment at the National University Hospital of Iceland (chemotherapy, radiation therapy, or other nonhormonal cancer medication) at the start of participation; (2) aged ≥18 years; (3) speaks Icelandic; (4) has the capacity to give informed consent; and (5) owns and knows how to operate a smartphone.
All participants provided informed consent before enrolling in the study. The protocol was approved by the National Bioethics Committee (institutional review board registration number VSN-21-102). This study was conducted in accordance with the ethical principles of the Declaration of Helsinki 2008.
After signing informed consent forms, participants completed a preintervention QoL questionnaire on the web, and exercise physiologists or physical therapists at the cancer clinic collected information about baseline physical measurements, physical fitness and body composition. Participants were also instructed to download the Sidekick smartphone app and received an access code to the program. During the intervention, data on participants’ retention, engagement, and self-reported in-app activity were collected through the app. QoL, fitness, and body composition measurements were repeated after the intervention, and participants’ feedback on the program was collected through a web-based satisfaction questionnaire.
The program was delivered through the Sidekick app, which was created by a group of data scientists, designers, gamification experts, behavioral scientists, psychologists, medical doctors, and other health care professionals and uses the principles of behavioral economics combined with gamification elements to achieve behavioral modifications for the primary and secondary prevention of lifestyle-related chronic diseases [
The intervention was designed to provide patients with cancer with tools to better deal with side effects during cancer treatment and to improve their overall QoL, with the main focus on stress management and improving sleeping habits. A general program overview is provided in
Presentation of main program missions and expected outcomes.
Mission type | Content or action | Outcome |
Education | Videos and other content every day | Increased knowledge of tools for building healthy habits |
Food logger | Log vegetables and water consumed every day | Healthier eating habits and better nutrition |
Step counter | Log number of steps every day | Increased awareness and motivation for physical activity |
Guided meditation | Meditate 3 times per week | Improved mental health and stress management |
Patient-reported outcomes | Indicate energy levels, stress levels, and quality of sleep 3 times per week | Increased self-awareness |
The Sidekick app interface. Program overview (left): the program was composed of 4 weekly modules with introduction on week 1, followed by modules on stress and sleep, nutrition, and mindfulness in the following weeks. Users could access educational videos in each topic (middle) as part of their daily missions. The missions included reaching step goals and logging food and water intake (right).
Retention and engagement were assessed using data on user-reported interactions by completing missions on the Sidekick app. Treatment completion was defined as being active in-app at least 3 of 4 weeks (or 75% of the program duration) and completing the prestudy and poststudy QoL questionnaires. Although previous studies found that attrition rates can be as high as 50% [
Participants’ health-related QoL was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 (QLQ-C30). QLQ-C30 is a clinically validated and well-established questionnaire composed of 30 questions that measure QoL across 3 domains: functional scales (physical, role, emotional, cognitive, and social), symptom scales (fatigue, nausea or vomiting, pain, dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties), and global health status [
Aerobic fitness was measured using the Åstrand submaximal test on a cycle ergometer (Monark) [
Body composition was measured using the InBody 770 bioelectrical impedance analyzer [
Step counts were automatically measured by the app based on data from the built-in accelerometer of the smartphone. However, at the end of each day, the steps had to be manually registered by the user by clicking
PROs on quality of sleep, stress, and energy levels were measured using the app 3 times a week. Users received these as part of their daily missions on 3 random days of the week and were composed of a prompt (“Please indicate last night’s quality of your sleep/today’s energy level/today’s stress level”) and a 10-point visual analog sliding scale, where 10 represents the highest sleep quality, energy levels, or stress levels. Users could rate these at any time of the day but received no additional reminders for them.
Characteristics are presented as mean and SD with the corresponding number and percentage of participants. User engagement information is presented as medians and IQR for weekly active days and total active days (active days out of 28 days), as these were nonparametric variables. Active days were defined as days when the user logged at least one mission. The average number of daily mission interactions is the number of events a user completes per mission; it was calculated as total mission interactions divided by total active days and is presented as mean and SD. Step goal attainment is shown as the number and percentage of users who used a step counter in the first and last weeks, along with weekly step counts as mean and SD, and step goal attainment is shown as the percentage of users who used the step counter.
Scores from QLQ-C30 were calculated according to instructions in the scoring manual (open source) [
PROs on sleep, stress, and energy levels were compared at the beginning and end of the study using 2-tailed paired
In total, 30 patients with cancer were initially enrolled in the program; 1 (3%) did not download the app and was therefore excluded from further analysis, and 29 (97%) completed the program with in-app activity in 3 of 4 weeks (
The baseline characteristics and measurements are shown in
Participant flow through the study.
Participants’ baseline characteristics (N=29).
Characteristics | Value | ||
Age (years), mean (SD) | 52.6 (11.5) | ||
Female, n (%) | 23 (79) | ||
|
|||
|
Breast cancer | 18 (62) | |
|
Other cancer | 11 (38) | |
|
Stage I-III | 21 (72) | |
|
Stage IV (metastasis) | 8 (28) | |
|
|||
|
Chemotherapy | 26 (90) | |
|
Radiation therapy | 2 (7) | |
|
Both | 1 (3) | |
|
|||
|
Normal weight (18.5-24.9) | 5 (17) | |
|
Overweight (25.0-29.9) | 9 (31) | |
|
Obese (≥30.0) | 14 (52) | |
|
|||
|
Height (cm) | 168.3 (7.5) | |
|
Weight (kg) | 85.0 (17.6) | |
|
BMI (kg/m2) | 30.0 (5.8) | |
|
|
||
|
|
Femalea | 41.2 (7.6) |
|
|
Maleb | 26.5 (8.6) |
|
|
||
|
|
Femalea | 32.6 (11.8) |
|
|
Maleb | 25.4 (17.5) |
|
|
||
|
|
Femalea | 48.1 (5.5) |
|
|
Maleb | 63.1 (9.3) |
|
|||
|
Femaled | 27.7 (8.1) | |
|
Malee | 31.2 (11.6) |
aData available for 23 participants.
bData available for 5 participants.
cVO2max: maximum oxygen uptake.
dData available for 15 participants.
eData available for 6 participants.
Engagement metrics are presented in
Data on step counter use show that all 29 participants used this function in the first week, with 72% (21/29) achieving the set target. The number of users logging their steps remained high in the last week (27/28, 96% of active users), with 68% (19/28) reaching the target goal (
Engagement metrics (N=29).
Metric | Value |
Completion ratea, n (%) | 28 (97) |
Weekly active days, median (IQR) | 6.8 (5.8-6.8) |
Total active days, median (IQR) | 27.0 (23.0-27.0) |
Daily mission interactions, mean (SD) | 7.7 (1.9) |
Highly engaged usersb, n (%) | 21 (72) |
4-week retention, n (%) | 28 (97) |
aCompleted 75% of the program and all preprogram and postprogram questionnaires.
bUsers who were active in the app at least five days a week.
In-app measured step counts and goal attainment (N=29).
Metric | Week 1 | Week 4 |
Used step counter, n (%) | 29 (100) | 27 (96) |
Attained step goal, n (%) | 21 (72) | 19 (68) |
Weekly step counts, mean (SD) | 21,306 (11,411) | 24,449 (17,445) |
Overall, 28 participants completed the postintervention satisfaction survey. These results showed that program acceptability was high, with 89% (25/28) of participants likely to recommend the program to others and 93% (26/28) who found the Sidekick app user friendly. Regarding program content, of the 28 participants, 26 (93%) found the educational content helpful, 23 (82%) said they felt better equipped to deal with their illness after participating in the program, and 24 (86%) said the app helped them remember to take their medication. With regard to the lifestyle coaching feature, 93% (26/28) of the participants said they found the weekly messages from the coach useful, but only 54% (15/28) somewhat agreed with the statement that they would have liked more feedback from the coach. Overall, 86% (24/28) of participants agreed that the program had positive effects on their lives and well-being.
The results of the self-reported QoL questionnaire are shown in
Functioning in all subcategories remained the same or increased in approximately two-thirds of the participants, with most participants seeing an improvement in role functioning (
Quality of Life Questionnaire C30 scores for each item scale at inclusion and follow-up.
Domain | Inclusion (n=28) | Follow-up (n=28) | ||
|
||||
|
Physical | 85.5 (10.7) | 83.8 (14.1) | .39 |
|
Role | 60.7 (20.9) | 62.5 (26.7) | .54 |
|
Emotional | 72.3 (16.5) | 73.5 (18.0) | .63 |
|
Cognitive | 69.0 (21.6) | 70.8 (20.6) | .65 |
|
Social | 58.3 (23.4) | 64.3 (21.6) | .21 |
|
||||
|
Fatigue | 35.7 (14.3) | 40.1 (22.1) | .55 |
|
Nausea or vomiting | 8.3 (12.4) | 8.9 (14.0) | .67 |
|
Pain | 31.0 (20.1) | 22.6 (23.2) | .16 |
|
Dyspneaa | 22.2 (22.6) | 23.5 (27.4) | .94 |
|
Insomnia | 31.0 (25.5) | 29.8 (27.7) | .87 |
|
Appetite lossa | 19.8 (19.1) | 19.0 (26.3) | .48 |
|
Constipation | 11.9 (22.6) | 11.9 (20.7) | .85 |
|
Diarrhea | 11.9 (20.7) | 10.7 (18.3) | .74 |
|
Financial difficulties | 19.0 (30.7) | 15.5 (21.2) | .52 |
Global health status, mean (SD) | 61.6 (17.0) | 61.9 (15.8) | .78 |
a1 missing value; n=27 answers were analyzed.
Percentage of individuals with decreased, increased, or unchanged Quality of Life Questionnaire C30 scores on the functional and symptom scales. *1 missing value; n=27 answers were analyzed.
PROs on energy levels, quality of sleep, and stress levels collected within the app showed that they remained stable over time, with no significant changes (
Average weekly changes in users’ ratings of energy levels, quality of sleep, and stress levels (error bars show SD), with the number of users reporting these (n) each week shown under the graphs.
We carried out an exploratory correlation analysis between the QLQ-C30 and in-app–reported QoL measures to gain insight into the clinical validity of the QoL outcomes measured in the app (
Spearman rank correlation analysis of in-app quality of life (QoL) and Quality of Life Questionnaire C30 (QLQ-C30) item scores. The listed QLQ-C30 items below 0 are inversely correlated, while above 0, they are positively correlated with energy level, quality of sleep, and stress levels. Items that significantly correlate with either in-app QoL measure are shown in bold and are represented by large circles, while those items with no significant correlations are represented by small circles. *
This trial tested the feasibility of a DTx intervention targeted at patients with cancer in active treatment and gathered preliminary information on its effectiveness. We obtained encouraging results regarding retention and engagement; the program had a very high completion rate (97%) and high acceptability (>80%), and thus, the feasibility criteria were met. Engagement metrics painted a similar picture, with users staying active 96% of the time, or 27 out of 28 days, and completing on average 7.7 (SD 1.9) missions a day.
These engagement metrics are somewhat higher than those reported in other studies. A recent systematic review of 6 studies found that the average retention rate of digital behavioral interventions was 90.7% among cancer survivors [
In terms of goal attainment, >70% of users were able to achieve their step goals in this trial, and the average step count (approximately 3000-3500 per day) was comparable with that found in other studies with patients in active cancer treatment [
The patients in this study were on average more obese than similar patient populations in other trials [
The global QoL of patients with cancer found in this study agrees with scores reported from patients with cancer in previous studies [
We found that the in-app PROs positively or negatively correlated with certain QLQ-C30 items as expected. Higher energy levels indicated higher role and social functioning and lower fatigue and constipation, while higher stress levels indicated lower cognitive and emotional functioning. Surprisingly however, higher energy levels were also associated with increased loss of appetite and nausea or vomiting, and better sleep was associated with reduced appetite. It is important to further assess these associations in larger sample trials to better validate PROs used by the Sidekick app.
The strengths of this study were excellent retention, engagement, and questionnaire completion, which eliminated the need to correct for missing data. Feedback from the patients suggested that the supportive and familiar environment at the rehabilitation clinic could have played a key role in this finding. An additional strength is the multidisciplinary nature of the intervention, which has been shown to benefit the rehabilitation of patients with breast cancer [
A limitation of this study was the small sample size, which was composed of self-selected and likely self-motivated individuals. This restricts the generalizability of the results and reduces the study power for testing preliminary program efficiency. Another limitation arising from the study design was the short program duration of 4 weeks, which is likely too short a time frame to detect significant changes in physical and mental health parameters. Finally, the known limitations of the app are the lack of automatic step counting and the fact that step count missions could not be completed retrospectively for previous days; thus, if users did not claim their steps, the records showed 0 steps for the given day. Therefore, this feature likely underestimated the real physical activity that participants completed and hence should be further optimized in future programs and trials.
On the basis of evidence gathered, digital support delivered through the Sidekick app is feasible for patients with cancer, and a large-scale RCT can be initiated. Preliminary results suggest that participants’ health-related QoL remained stable for 4 weeks, but a longer, controlled trial will be required to gauge the efficacy of the digital intervention for improving QoL. Changes in the most burdensome side effects, fatigue and pain, should also be the primary focus and assessed using specific measures in future trials. In addition, the digital program could be further tailored to the cancer experience by including education about treatments and specific side effects, providing symptom tracking and medication reminders, and adapting the assigned daily tasks and workload to the individual’s stage on the cancer treatment journey and actual energy and motivation levels.
Details of the weekly education content.
digital therapeutics
patient-reported outcome
Quality of Life Questionnaire C30
quality of life
randomized controlled trial
maximum oxygen uptake
This study was sponsored by Sidekick Health. The authors thank Kolbrún Halla Gudjónsdóttir for providing support with recruitment and coaching at Ljósid as well as all the staff members at Ljósid who helped with the study procedures.
GHG, JM, ÁB, MLÁ, and HH are employees of Sidekick Health; in addition, SO is the cofounder of Sidekick Health.