Optimization of a mHealth Physical Activity Promotion Intervention With Mindful Awareness for Adolescent and Young Adult Cancer Survivors

Inclusion Criteria

Inclusion Criteria: For YACS * Diagnosis of nonmetastatic cancer (except non-melanoma skin cancer) within 5 years from the time of screening / study overview session * Age Diagnosis of cancer between 18-39 years at time of diagnosis and at time of screening / study overview session * Three or more months post-completion of primary treatment (i.e., surgery, chemotherapy, and/or radiation); may still be undergoing endocrine or hormone therapies * Score of 0 on two of the Exercise Preparticipation Health Screening Questionnaire items or willingness to obtain medical clearance from a primary care physician or oncologist * Self-report engagement in \<60 minutes total each week of MVPA at time of screening / study overview session * Ownership of a smartphone that is either an iPhone (version 5 or greater) or an Android (version 5.0 or greater) * Internet access * Fluency in spoken and written English * Willingness, at time of screening / study overview session, to find a Buddy (someone who knows about their cancer and participation in this study and who is willing to participate by supporting them during the 6-month study), if assigned to that condition For "Buddies" * Friend, co-worker, caregiver or family member of a participating YACS * Age 18 years or older * Score of 0 on the Exercise Preparticipation Health Screening Questionnaire or willingness to obtain medical clearance from a primary care physician * Ownership of a smartphone that is either an iPhone (version 5 or greater) or an Android (version 5.0 or greater) * Internet access * Fluency in spoken and written English * Willingness to share their Fitbit data with the study team Exclusion Criteria: * For YACS: Diagnosis of non-melanoma skin cancer * Absolute contraindications to exercise (i.e., acute myocardial infarction, severe orthopedic conditions), metastatic disease, or planned elective surgery * Currently pregnant or plans to become pregnant in the next 12 months * Plans to move out of the United States in next 18 months * For YACS: Current enrollment in another dietary or physical activity trial * Inability to provide informed consent * Prisoners or other detained individuals