DESCRIPTION: Innovative treatments for the rehabilitation of the growing number of cancer survivors are sorely needed. Breast cancer patients who have completed medical treatment for cancer experience considerable psychological distress (e.g., anxiety, depression, poor body image), and physical symptoms of fatigue and weight gain that can last several years post-treatment. With increased survival rates, these psychosocial difficulties have become more salient. The investigators propose to offer early-stage breast cancer survivors an innovative treatment program to ameliorate some of the physical and psychological symptoms that accompany cancer diagnosis and treatment, and to facilitate resumption of life-tasks. Exercise participation in other populations has been shown to reduce affective distress, improve body image, increase sense of empowerment, and reduce fatigue and weight gain. This study proposes to examine the feasibility of a home-based moderate exercise program among breast cancer survivors and the benefits that these women could gain from participating in such a program. One hundred and thirty-four women with early-stage breast cancer (Stages 0, I and II diagnosed within the past two years) who have completed surgery and adjuvant therapy will be invited to participate. Subjects will be randomized to a 12-week home-based exercise program or a contact control condition. Participants will be asked to complete standardized measures of exercise, mood, quality of life, physical symptoms, body image and coping before treatment, at 12 weeks, 6 months and 9 months (3 and 6 month follow-ups). Exercise participation will be measured by self-report and by Caltrac accelerometers. A 12-minute walk test will be conducted at pretreatment and at 12 weeks. Analyses of covariance will be used to assess treatment effects and regression analyses will be used to determine which types of patients benefit from this unique cancer rehabilitation program. By evaluating the effects of a home-based exercise program on quality of life and mood in cancer survivors, this study can serve as a precursor to examining the long-term effects of exercise on quality of life and cancer recurrence. This study also raises the intriguing possibility of elucidating the physiological effects of exercise on hormonal and immune mechanisms involved in breast cancer.