activity during therapy and changes in metabolic rate that are associated with the menopause transition. Use of adjuvant therapy and onset of menopause are the strongest clinical predictors of weight gain when assessed 1 year from treatment (Goodwin et al., 1999a). Recent evidence suggests that obesity prior to diagnosis and decreased current physical activity, but not adjuvant treatment, were associated with obesity among breast cancer survivors when assessed approximately 6 years from the time of diagnosis (Herman et al., in press). Obesity can have serious health consequences and also impair psychosocial adaptation. Of great concern is the suggestion by some studies that weight gain may increase a woman’s risk of disease recurrence and death (Chlebowski et al., 2002a; Carmichael and Bates, 2004; Dignam and Mamounas, 2004; Kroenke et al., 2005). Exercise and dietary interventions may help alleviate weight gain among women receiving adjuvant breast cancer chemotherapy (Rock and Demark-Wahnefried, 2002; Demark-Wahnefried and Rock, 2003).

Estrogen is known to contribute to the risk of breast and endometrial cancer, but to be protective against osteoporosis. Women with breast cancer, who are more likely to have had relatively high exposure to estrogens, have a significantly lower risk of osteoporosis, according to both epidemiologic and clinical research (Lamont and Lauderdale, 2003; Lamont et al., 2003). Premenopausal women who experience ovarian failure following chemotherapy are, however, at much higher risk for accelerated bone density loss.

Osteoporosis is characterized by a reduction in bone density and strength, which predisposes individuals to an increased risk of fractures (Box 3-6). Post-menopausal women average a decline in bone mineral density of about 1 to 2 percent per year, but in one study of 35 premenopausal