 A multicenter phase III open randomised trial of the efficacy of exercise in the prevention of long-term adverse effects of adjuvant treatments and breast cancer recurrences in women with primary breast cancer. The aim of the study is to investigate whether regular exercise training could reduce the long-term side effects of adjuvant treatments of primary breast cancer and improve quality of life and well being. Large controlled prospective studies are needed to confirm the preliminary findings of exercises benefits in cancer patients, and to investigate the type, the frequency, intensity and tolerability of exercise training in cancer patients, before any clinical recommendations can be given. Prevention of osteoporosis, improvement of weight control, and muscular and cardiovascular fitness is been waited. The second aim of the study is to investigate, whether regular exercise training reduces the risk of breast cancer recurrence, prevents other diseases and reduce all-cause mortality and is cost effective in women with primary breast cancer. 