Bone loss during neoadjuvant/adjuvant chemotherapy for early stage breast cancer: A retrospective cohort study

The present study aimed to evaluate the extent of loss in bone mineral density (BMD) during neoadjuvant and adjuvant chemotherapy for early stage breast cancer. A retrospective cohort study was conducted to quantify the loss of BMD one year following the start of chemotherapy and to identify potential risk factors of excessive BMD loss. Based on DXA-scans prior to and one year following chemotherapy, the loss of BMD was evaluated in early stage breast cancer patients treated from January 2012 to December 2014. A total of 492 patients received either eight cycles of neoadjuvant or six cycles of adjuvant chemotherapy. The final analysis included 152 patients with two DXA-scans. The patients had a significant loss of BMD in the hip [-0.0124 g/cm² (95% confidence interval (CI) -0.018; -0.007) P<0.001] and in the lumbar spine [-0.029 g/cm² (95% CI: -0.036; -0.023) P<0.001] corresponding to a change of -1, 3 and -2, 9%, respectively. Premenopausal women had a significant loss of BMD in the lumbar spine -0.045 g/cm² equivalent to -4.3%, which was significantly increased compared with postmenopausal women (P<0.001) in the univariate analysis, whereas only a trend persisted in the multivariate analysis (P=0.60). There was no significant difference in BMD loss (lumbar spine P=0.176) between patients receiving adjuvant and neoadjuvant chemotherapy. In conclusion, neoadjuvant and adjuvant chemotherapy is associated with significant BMD loss in both hip and lumbar spine. Furthermore, the results of the present study indicate that premenopausal women have a pronounced BMD loss in the lumbar spine. Further studies investigating osteoporosis prophylaxis in premenopausal patients are warranted.