In this study of 174 male veterans with ADT-treated prostate cancer, we found that only 34% had either a recent DXA or concurrent pharmacological interventions for osteoporosis prevention or treatment. Even with less stringent management criteria, only 41% of the patients ever received DXA testing or therapeutic interventions. After excluding subjects with metastases, only 26% of the cohort was currently being managed for osteoporosis and 34% were ever managed. Whereas all subjects were at risk for osteoporosis because of their ADT treatment, a substantial proportion of even those with additional risk factors for osteoporosis or fracture, including diagnosis of diabetes, smoking, alcohol use or prescriptions for corticosteroids, phenytoin or thyroid hormone, were not evaluated or treated for osteoporosis.
Failing to appropriately address osteoporosis in men with ADT-treated prostate cancer is problematic because longer durations of treatment (1.9 years or more) are associated with increased risk for osteopenia, osteoporosis, and non-pathologic fractures.30
The numbers needed to harm for a fracture occurrence 12 to 60 months after diagnosis of prostate cancer is estimated to be 28 for men treated with GNRH-agonist and 16 for orchiectomy.31
The reasons why prostate cancer patients on ADT are not evaluated for osteoporosis or provided pharmacological interventions are probably multifactorial. One potential problem is that bone mineral density testing guidelines for high-risk populations are not uniform.32
(Table ) may be confusing to providers and patients.32
Although risk factor assessments can be used to identify patients for BMD testing, there is no consensus about the most important risk factors.35
Primary care providers may be unaware that ADT-treated men with prostate cancer are at risk for osteoporosis. Furthermore, expert opinion guidelines for managing osteoporosis in these patients have been published only in cancer and urology journals.21–24
Other barriers to osteoporosis screening include the paucity of clinical trial data assessing the efficacy of BMD testing for fracture prevention, the cost of testing, the limited availability of testing facilities, and the belief that results would not affect treatment decisions.36,37
Bone Mineral Density Testing Recommendations for Men
Barriers to osteoporosis treatment include medication costs, potential adverse effects, and uncertainty about osteoporosis treatment efficacy in high-risk individuals.38
Whereas there are effective treatments for male osteoporosis,39,40
the Food and Drug Administration (FDA) has not specifically approved any agents for preventing or treating osteoporosis in men with ADT-treated prostate cancer. Zoledronate is FDA-approved for use in metastatic hormone-refractory prostate cancer because it decreased skeletal events (including pathologic fractures) in these patients.41
In clinical trials with nonmetastatic prostate cancer patients on ADT, zoledronate increased mean bone mineral density,11
IV pamidronate prevented bone loss,12
and once-weekly oral alendronate prevented bone loss, substantially improved bone mass, and decreased bone turnover.42
Uncertainty about who is responsible for osteoporosis management in prostate cancer patients poses another problem. Prostate cancer care is often multidisciplinary and patients see primary care physicians, medical and radiation oncologists, and urologists. Calls have been made for primary care physicians and subspecialists to share responsibility for osteoporosis management in order not to miss screening, diagnostic, and treatment opportunities.43
Whereas complicated cases of osteoporosis may benefit from specialist expertise,44–46
a case can be made for primary care providers to take the lead in osteoporosis management because they are already providing other preventive services.47
In addition, primary care providers will be managing newly recognized nonosteoporotic ADT complications, including diabetes and cardiovascular disease.48
The low rate of osteoporosis management we observed is consistent with 1 study we found addressing this issue. In Tanvetyanon’s study,25
which included men with bone metastases, only 14.7% of patients received at least 1 intervention for osteoporosis prevention or treatment, as defined by DXA scanning within the previous 3 years or bisphosphonates, vitamin D, calcium, calcitonin or estrogen within the past year. That population was drawn from a large, suburban hospital and was mostly non-Hispanic White (64%) or African American (23%), and the only predictor for receiving osteoporosis intervention was bone metastases. Our subjects differed substantially because we had a racially/ethnic diverse population (43% were Hispanic, Native American, African American or Asian American) and a large rural population (36%). Although both these studies involved veterans, limited management was consistently found across all races and ethnicities and for both urban and rural populations, suggesting that this is a wide spread issue in prostate cancer patients on ADT treatment.
There are several imitations of this study. As this was a retrospective chart review, accuracy of data was dependent on comprehensiveness of documentation and consistency of data abstraction. This study could not determine whether a provider’s decision to order a DXA or prescribe medications such as calcium and vitamin D was influenced by the ADT treatment. Patients with bone metastases were more likely to receive IV bisphosphonates and see oncologists. Therefore, these treatments may have been for preventing pathologic fractures or treating hypercalcemia rather than for osteoporosis management. By including patients with bone metastases, we may have inflated the estimate of osteoporosis management related to ADT treatment. However, this allowed us to compare our results with the other study addressing this issue that we found in the literature.
We were also unable to ascertain why patients were not evaluated or treated for osteoporosis. Patient resistance has been documented even amongst groups that have sustained a low-impact fracture and are at high risk for future osteoporotic fractures.49
Osteoporosis risk may be a low priority for patients within the context of their general health care.50
We did not evaluate whether a limited life expectancy influenced clinical decisions regarding osteoporosis management. We examined charts from only one Veterans Administration system. Although this system included a main hospital and outlying community-based outpatient clinics (CBOCs), our results may not be generalizable to other sites. Although all study patients received ADT through the VA, many of the patients followed at the CBOCs have dual care. Based on chart reviews, we could not ascertain whether they received testing or medications from non-VA providers. The CBOCs do not have DXA scans at the facility, which could impact screening rates. Although Hispanic ethnicity significantly predicted receiving less appropriate management, we could not identify race or ethnicity for a substantial proportion of our subjects. Therefore, our findings regarding racial/ethnic disparities in osteoporosis management should be interpreted cautiously.
Our study demonstrated low rates of osteoporosis management for prostate cancer patients on ADT. These findings are concerning given the known increased risk for osteoporosis associated with ADT and the availability of effective treatments to prevent bone loss or increase bone mass in these patients. There are many potential barriers to osteoporosis management in this population. Further research is needed to determine optimal strategies for ensuring that men with ADT-treated prostate cancer receive appropriate screening, prevention, and treatment for osteoporosis.