Int J Fertil 50 231 Exercise for Breast Cancer Survival: The Effect on Cancer Risk and Cancer-Related Fatigue (CRF) Jennifer A. Hewitt*† Kefah Mokbel, M.S.† Ken A. van Someren, Ph.D.* Andrew P. Jewell, Ph.D.* Rachel Garrod, Ph.D.† *School of Life Sciences Kingston University Kingston Upon Thames Kingston, Surrey, United Kingdom †St. George’s University of London Tooting, London, United Kingdom ABSTRACT: To date, all epidemiological research in this area has focused on the relationship between physi- cal activity level and the risk of breast cancer in healthy women, or more recently, those who have recovered from the disease. Most of this research highlights the fact that those women who are physically active are at a reduced risk of the disease. Although physical activity is similar to exercise, it lacks the specificity of a pre- scribed exercise training program. Consequently, such research can only be viewed as a promising indicator of the beneficial effect that regular exercise may have for breast cancer survivors. Furthermore, due to the nature of such research, there has been a failure to provide specific evidence concerning the most suitable modality, duration, intensity, and frequency of training for risk reduction in breast cancer survivors. Thus, evidence aid- ing the correct prescription of exercise for this population has been lacking. More promising evidence is pro- vided by randomized controlled trials, which examine the effect of exercise on specific risk factors and pro- vide convincing scientific rationale for the use of exercise among breast cancer survivors. These studies not only provide understanding of the physiological mechanisms by which exercise can be effective at aiding a reduction in breast cancer risk, but also allow conclusions on the correct prescription to be drawn. Additionally, exercise has proven to be effective in combating cancer-related fatigue (CRF), significantly improving both quality of life outcomes (QOL) and physiological capacity in women who have survived breast cancer. In order to promote a wider understanding of the beneficial effect that exercise holds for this popula- tion regarding reduction of breast cancer risk and CRF, this review discusses this research, making conclusions regarding the necessary training prescription to elicit such benefits. Int J Fertil 50(5):231–239, 2005 KEY WORDS: breast cancer survivors, exercise, breast cancer risk, cancer-related fatigue (CRF) INTRODUCTION I T IS ESTIMATED THAT 1 IN 7 WOMEN from first world countries will suffer from breast cancer during their lifetime [1]. Although sur- vival rates are high (85% in the first 5 years) [1], the reduction of risk factors within this population is crucial to longevity. Furthermore, it has been shown that as many as 61% to 76% of cancer sur- vivors report cancer-related fatigue (CRF), which may persist for up to 10 years post treatment [2]. As the symptoms (e.g., decreased stamina, muscle Int J Fertil, 50(5), 2005 p. 231–239 © 2005 Controversies in Obstetrics and Gynecology, Polish Society of Perinatal Medicine, the International Society of Reproductive Medicine, the World Foundation for Medical Studies in Female Health and the Center for the Study of Cryopreservation of Oocytes and Spermatozoa HewittArticle 11/29/05 2:23 PM Page 231 NOT FOR REPRODUCTION