For patients with cancer who received hormone-disrupting chemotherapy, improved long-term survival has come with a catch: decreased bone mineral density (BMD). Survivors of prostate and breast cancer and their clinicians need to monitor bone and dental health because the essential hormones used for bone remodeling have been depleted by androgen deprivation therapy and premature menopause and chemotherapy, respectively.1

Cancer treatment-induced bone loss can occur when the body is depleted of androgens and estrogens, which are essential for bone growth and maintenance.1 Evidence also points to the role of other hormones in maintaining bone health, including inhibins and activins.1

Breast Cancer and Bone Health

With more women surviving breast cancer, in large part because of the availability of tamoxifen and aromatase inhibitor therapy, lifelong monitoring for bone health has never been more important.2 In women who received chemotherapy with ovarian-suppressing agents, treatment-related lumbar spine bone loss was up to 10% after just 1 year of therapy.2

Antiresorptive medications may help prevent bone loss related to cancer treatment. A 3-year study found that 4 mg zoledronic acid every 6 months during receipt of adjuvant endocrine therapy increased bone mass in women with early-stage breast cancer who had undergone premature menopause because of cancer treatment.2

One of the main causes of bone loss in postmenopausal women who received adjuvant endocrine therapy has been aromatase inhibitors, which are linked to a 2% loss of BMD at the lumbar spine annually.2 Several international medical organizations introduced a joint statement in 2017 on monitoring and treating women who received aromatase inhibitor therapy to prevent bone loss and the resulting fractures.3 Guidelines recommend denosumab or bisphosphonates for postmenopausal women at high risk for fractures (ie, patients with a baseline T score of <-2.0 or with ≥2 clinical risk factors).3 Premenopausal women at high risk for fractures should receive zoledronic acid or clodronate to prevent bone loss and bone metastases.3

The consensus bifurcates according to the primary risk: denosumab is recommended for women whose primary concern is fracture risk, and bisphosphonate therapy for those at high risk for cancer recurrence.3 For women whose T-score is >-2.0 with no additional risk factors, the guidelines suggest exercise, supplements of vitamin D and calcium, and monitoring BMD every 1 to 2 years.3