Bone mineral density after adjuvant chemotherapy for premenopausal breast cancer.

Lumbar bone mineral density (BMD) determination by dual photon absorptiometry was used to study the influence of adjuvant chemotherapy for premenopausal breast cancer on the risk of premature osteoporosis. Six cycles of combination chemotherapy caused ovarian failure in 31 of 44 (71%) women, amenorrhoea mostly already beginning during treatment. In contrast, only seven of 44 (16%) women, who were pair-matched for age and year of breast cancer surgery and had not been treated with chemotherapy, were post-menopausal at the time of measurement. The mean interval after breast surgery was 3.5 years. The significantly decreased BMD in the treated group (1.17 compared to 1.29 g cm-2) could only be explained by the high incidence of menopause in these women, which on average occurred 10 years prematurely. Extrapolation of these findings suggests that adjuvant chemotherapy may precipitate osteoporotic fractures by some 10 years in a considerable proportion of women cured of premenopausal breast cancer.