GutCheck: Optimization of a Personalized Mobile Health App for Survivors of Gastrointestinal Cancer

There are two components to the study: a patient and a clinician study. The clinician study will include one-hour semi-structured interviews with oncology specialists to identify facilitators and barriers to integrating digital diet interventions into the clinical workflow, and to understand their needs and preferences for digital diet interventions. The patient study aims to investigate initial feasibility, efficacy and acceptability of the GutCheck app and intervention. It will last 9 weeks and involves 2 study visits and 2 active phases with a transition week and optional transition visit between phases. During active phases, participants will be asked to use the GutCheck app every day. Prior to the first active phase, participants will go through informed consent and app training. The first active phase will last two weeks and will focus on tracking participants' diet, gastrointestinal (GI) symptoms, and stress. The data collected during the first active phase will be used to identify any potential trigger foods that may contribute to GI symptoms, but only if the participant reports experiencing GI symptoms. Between active phases, participants will have one Transition Week, where results from the first phase are given to the participants with the option to attend a Transition Week Visit. The second active phase will last four weeks and will involve the message intervention. A single-blind, micro-randomized trial design will be used to repeatedly randomize participants to different intervention combinations, determining both the timing and frequency of intervention message delivery throughout the day. Lastly, there will be an exit visit and interview within a week from the intervention to collect post-intervention measures and ask about the participant's experience with the GutCheck app.

Study Overview

• Status: Not yet recruiting
• Conditions: Gastrointestinal Cancer; Survivorship; GI Cancer; Gastrointestinal; Mobile Health; Gastrointestinal Symptoms; Gut Health
• Intervention / Treatment: Diagnostic test: Stool Sample; Other: App Activity

• Study Type: Interventional
• Enrollment (Estimated): 200
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Annie W. Lin, PhD, RD; Phone Number: (612) 356 2001; Email: awlin@umn.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion

Survivors of GI cancer are eligible if they are:

• ≥18 years old
• reside in or have received cancer care in Minnesota
• own a smartphone • consent to install the GutCheck app and discontinue diet tracking in other lifestyle apps (e.g., MyFitness, Fitbit, Noom).
• are English-speaking
• have received a GI cancer diagnosis (e.g., esophageal, gastric, colorectal, liver, pancreatic, etc)
• At least 2 months post-cancer treatment

Inclusion criteria for oncology specialists (oncologists, advanced practice providers, nurses, dietitians, and patient navigators) include:

• Have interacted with at least 1 cancer patient or survivor in the past month.
• Have experience working with electronic health records (EHR).

Exclusion

• Currently pregnant (Patient Study ONLY)
• Pregnancy status may be self-reported by the participant.
• Individuals who are postmenopausal, surgically sterile, or otherwise unable to become pregnant are not subject to this exclusion.
• Active cancer or receiving treatment for another cancer.
• Currently taking or has taken antibiotics in the last 3 months.
• Diagnosis of inflammatory bowel disease (e.g., Crohn's Disease, ulcerative colitis), and/or celiac disease.
• Involuntary weight loss of 10% or more of usual body weight within 6 months, or involuntary loss of 5% or more of usual body weight in 1 month.

Oncology specialists' exclusion criteria include:

• Unable to participate in an interview

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Personalization Level - No; The "no personalization" group will receive generic push messages based on United States Department of Agriculture and Centers for Disease Control and Prevention recommendations. Within their personalization level, participants will be automatically randomized daily to varying message frequency (one vs. three times per day) and timing (preferred times vs. established times). After each message, all participants will be asked to evaluate whether the message was useful using a 3-point Likert-type visual scale in the app.	Diagnostic test: Stool Sample; Participants who were selected to collect their stool samples will be mailed their second kit before the last week (week 8) of intervention. Participants will collect their stool sample during week 8 and mail them to be processed prior to the Exit Interview Visit.; Other: App Activity; Participants will be asked to log their food and beverages, stress, and gastrointestinal symptoms daily. They will also track physical activity.
Active Comparator: Personalization Level - Low; The "low personalization" group will receive similar messages, with occasional use of their names and references to GI cancer. Within their personalization level, participants will be automatically randomized daily to varying message frequency (one vs. three times per day) and timing (preferred times vs. established times). After each message, all participants will be asked to evaluate whether the message was useful using a 3-point Likert-type visual scale in the app.	Diagnostic test: Stool Sample; Participants who were selected to collect their stool samples will be mailed their second kit before the last week (week 8) of intervention. Participants will collect their stool sample during week 8 and mail them to be processed prior to the Exit Interview Visit.; Other: App Activity; Participants will be asked to log their food and beverages, stress, and gastrointestinal symptoms daily. They will also track physical activity.
Active Comparator: Personalization Level - High; The "high personalization" group messages will be further tailored to age and gender to provide social comparisons. This group will receive food-related GI messages based on their responses from the personalization quiz during Week 1. Messages will emphasize affordable, commonly available foods to increase likelihood of accessibility. Within their personalization level, participants will be automatically randomized daily to varying message frequency (one vs. three times per day) and timing (preferred times vs. established times). After each message, all participants will be asked to evaluate whether the message was useful using a 3-point Likert-type visual scale in the app.	Diagnostic test: Stool Sample; Participants who were selected to collect their stool samples will be mailed their second kit before the last week (week 8) of intervention. Participants will collect their stool sample during week 8 and mail them to be processed prior to the Exit Interview Visit.; Other: App Activity; Participants will be asked to log their food and beverages, stress, and gastrointestinal symptoms daily. They will also track physical activity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adherence of Diet Tracking	Average count of days where the participant tracked at least two episodes a day.	1 year
Adherence of Gastrointestinal (GI) Symptom and Stress Level Tracking	Average count of days of GI symptom and stress tracking combination (i.e., once a day for two weeks for both).	1 year

Collaborators and Investigators

• Sponsor: Masonic Cancer Center, University of Minnesota
• Collaborators: Minnesota Clinical Trials Network

Study record dates

Study Major Dates

• Study Start (Estimated): December 1, 2026
• Primary Completion (Estimated): June 1, 2029
• Study Completion (Estimated): June 1, 2030

Study Registration Dates

• First Submitted: June 16, 2026
• First Submitted That Met QC Criteria: June 16, 2026
• First Posted (Actual): June 22, 2026

Study Record Updates

• Last Update Posted (Actual): June 22, 2026
• Last Update Submitted That Met QC Criteria: June 16, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Gastrointestinal Neoplasms
• Other Study ID Numbers: 2025LS135; MNCCTN038 (Other Identifier: Minnesota Clinical Trials Network (MNCCTN))

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No