Testing the Effects of Exercise on Colorectal Cancer Development After Treatment With Pelvic Radiation Therapy for Prostate Cancer

Inclusion Criteria: * Documented informed consent of the participant and/or legally authorized representative * Assent, when appropriate, will be obtained per institutional guidelines * Agreement to allow the use of archival tissue from diagnostic tumor biopsies * If unavailable, exceptions may be granted with study principal investigator (PI) approval * Age: 40-80 years * Body mass index (BMI): \> 25 kg/m\^2 * Has Apple Health application (app) on personal device with valid iOS operating software (i.e., iOS 15.0 or higher) * Has a registered MyChart/MyCityofHope account (or be willing to register for one) and the app downloaded onto personal device * Ability to read and understand English to review MyChart/MyCityofHope on-screen instructions to sync and share Apple Health data, and for safety during exercise testing * Previously diagnosed with localized prostate cancer * Completed pelvic radiotherapy 12-20 months ago * Presence of abnormalities (e.g., polyps, lesions) in the colon * Assessed for exercise participation as per pre-screening clearance via the Physical Activity Readiness Questionnaire (PAR-Q+) (stage 2 only) * Low physical activity, defined by \< 5,000 steps/day over the last 12 months as per Apple Health data (stage 2 only) Exclusion Criteria: * Enrollment in any other program (e.g., weight loss program) that may alter the impact of exercise on outcomes * Presence of any other concurrent, actively treated malignancy * Distant metastatic malignancy of any kind * Any other condition that would, in the Investigator's judgment, contraindicate the patient's participation in the clinical study due to safety concerns with clinical study procedures * Prospective participants who, in the opinion of the investigator, may not be able to comply with all study procedures (including compliance issues related to feasibility/logistics)