The Cancer Exercise app (CEA) is designed to promote physical activity among cancer survivors. The proposed randomized controlled clinical trial will investigate, in adults who have completed cancer treatment, the effects of a 12-week home-based exercise program, delivered using CEA, on physical activity levels. Participants will be randomized into one of two groups: (1) CEA or (2) Usual Care.

Inclusion Criteria:

• 18 to 85 years of age
• Diagnosed with stage I-III cancer
• Completed all primary cancer treatments (e.g., surgery, radiation, chemotherapy) at least 6 months prior to enrollment. Adjuvant endocrine therapy, CDK4/6 inhibitors, PARP inhibitors, immunotherapy, and bisphosphonates are allowed within 6 months of study enrolment and during study participation.
• Own a smartphone with data plan or access to WiFi (Apple or Android)
• Medical clearance provided or no medical clearance needed based on exercise preparticipation screening.

Exclusion Criteria:

• consistently engage in >300 min/week of moderate-intensity physical activity or 150 min/week of vigorous-intensity physical activity in the past 3 months
• receiving or scheduled to receive surgery or radiation during study participation
• have stage IV metastatic cancer or evidence of cancer recurrence
• have multiple myeloma
• have received bone marrow or hematopoietic stem cell transplant within past year
• are unable to walk without support or have severe weakness or balance problems that limit safe participation in exercise
• contraindications to participate in unsupervised exercise
• are pregnant
• unable to read, speak and understand English