The effects of adjuvant chemotherapy on bone density in postmenopausal women with early breast cancer

Purpose: Adjuvant chemotherapy for breast cancer can have adverse effects on bone. We investigated the effects of adjuvant chemotherapy on bone mineral density in postmenopausal women with early-stage breast cancer. Methods: We performed a chart review of all our breast center patients who had spine or hip bone density measured by dual-energy X-ray absorptiometry at our institution after treatment for stage I or II breast cancer. Patients who had other causes of metabolic bone disease were excluded. Multivariate regression analysis was used to adjust for confounding factors. Results were expressed as age-adjusted standard deviation units (Z scores). Results: Of the 130 eligible women, 36 (28%) received adjuvant chemotherapy and 94 (72%) did not. Mean adjusted bone density scores in both the hip (0.65 SD units; 95% confidence interval [CI]: 0.32 to 0.98 SD units; P = 0.0002) and spine (0.60 SD units; 95% CI: 0.01 to 1.19 SD units; P = 0.05) were significantly lower in patients who had received adjuvant chemotherapy compared with those who had not. Conclusion: Women who were postmenopausal when they developed breast cancer and who received adjuvant chemotherapy had lower bone density than those who did not. Whether this effect is caused by adjuvant chemotherapy remains to be determined.