Cancer-treatment-induced bone loss (CTBL) is a well-recognized co-morbidity that affects many cancer patients. Commonly used to treat breast and prostate cancer patients, hormone suppression therapy (HST) may accelerate bone loss, resulting in osteopenia or osteoporosis. Because of their broad clinical utility, lifestyle and dietary modifications, such as regular participation in bone-stressing exercise and calcium supplementation, are starting to play a much larger role in the prevention and treatment of CTBL. However, only limited information is available on the effects that these factors may have on bone mineral density (BMD). Purpose. The purpose of this investigation was to assess the degree of BMD change from the onset of HST to 6 months and to examine the impact that physical activity and calcium intake may have on BMD. Methods. Twelve subjects (8 females and 4 males) undergoing HST for breast or prostate cancer were enrolled in the study. BMD at the spine, dual femur, and total body was assessed by dual-energy x-ray absorptiometry at 0 and 6 months. In addition, subjects wore an accelerometer to assess physical activity level and completed a lifestyle questionnaire at baseline, 3, and 6 months after starting therapy. Aside from the 7 non-exercise subjects, 5 subjects chose to participate in The Cancer Exercise Program at Ball Memorial Hospital or complete bone-stressing exercises at home. Results. No significant changes in BMD were observed after 6 months of HST between the groups at any of the sites. When all subjects were examined together, a significant BMD decrease of 3.2% was observed at the lumbar spine. The accelerometer and lifestyle questionnaires revealed that the males were more active than the females and the exercisers were more active than the non-exercisers at both baseline and after 6 months of HST. Supplementation with calcium did not affect BMD changes at any site;although it is possible this is an effect of gender as all males were included in the same group. Lifestyle factors such as history of smoking and alcoholism were also examined, but were not correlated to changes in BMD. Conclusion. Treatment with HST results in decreases in BMD, particularly at the spine. Bone-stressing exercise helped maintain or improve total body BMD in 3 of the 5 subjects the exercise group. There appears to be no difference in BMD between those who supplemented with calcium and those who did not. / School of Physical Education, Sport, and Exercise Science

No abstract available. / Thesis (M.Med.Sc.)-University of KwaZulu-Natal, Durban, 2005.