Background: Physical exercise should be an essential component of the therapeutic plan for every person diagnosed with cancer. However, most of these patients are inactive and only a few of them receive prescription and follow-up for safe and effective exercise plans.

Objective: in a first experimental phase, we will evaluate actual implementation (reach and adherence) and clinical effectiveness (physical fitness, quality of life and symptoms) of the BIZI ORAIN (BO) exercise program, for all patients diagnosed with cancer, compared to standardized physical activity counseling. In a second, observational phase, we will evaluate the association between levels of physical activity actually performed by all the participants and their 12 months evolution, in terms of physical fitness, quality of life, symptomatology and survival.

Design: Hybrid study, with a first experimental phase in which patients diagnosed with cancer will be randomly assigned to two parallel groups, one that immediately performs the BO program for 12 weeks and the other one that performs the same programme three months later (delayed treatment). In the second phase, observational, the entire cohort of participants will be followed-up for one year. Population: Any person diagnosed with cancer in the previous two years (minimum sample size = 1013) free of bone metastases, hematological or other exercise contraindications.

BIZI ORAIN program: based on the "Life Now" program of the Australian Cancer Council, BO is a 12-week small-group exercise program supervised by specially trained instructors combining moderate to high intensity aerobic and strength exercises (three 1 hour sessions a week).

Outcome measurements: the main outcome variable will be the change in functional capacity at three months (400 meters walk test). Secondary variables include mortality, quality of life (general SF-36 and cancer specific quality of life -European Organization for Research and Treatment of Cancer QLQ-C-30-), symptoms (Cancer-related fatigue - Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue), exposure to physical activity level objectively registered with Actigraph wGT3X-BT accelerometer, chronic inflammation (C-reactive protein, adiponectin, and pro-inflammatory cytokines Il-1, Il-6 , and TNF-), body composition and bone health (dual-energy X-ray absorptiometry), measured at 0, 3, 6, and 12 months.

Analyses: changes observed in the outcome variables at three months will be compared between patients assigned to BO and to the reference group (delayed treatment) using analysis of the covariance, adjusted for baseline levels. To analyze the association between over time change in physical activity and the outcome variables mixed effects longitudinal models will be used for repeated measures throughout the 12 months of follow-up. Cox proportional hazards models will be used for the survival analysis. Qualitative analyses will combine a deductive approach with an inductive one based on Grounded Theory. In the deductive approach, the researchers will identify several thematic categories related to the Consolidated Framework for Implementation Research. Conclusions: BO is the first experience in Spain of a population-based exercise program that will guarantee, through a scientific evaluation, both clinical and implementation results. This will drastically advance the treatment of people suffering from cancer helping them to reverse the effects of their disease, the adverse effects of the therapies and to improve anti-cancer treatment efficacy, their quality of life and survival

Inclusion Criteria:

• People diagnosed with cancer within the previous 2 years, under treatment or finished

Exclusion Criteria:

• Neutropenia
• severe anemia
• bone metastases
• any musculoskeletal, cardiovascular or neurological disorder that could place the participant at risk of injury or illness resulting from the exercise program