For patients with high risk localized prostate cancer and advanced prostate cancer, it is important to think about bone health, especially if you will be receiving androgen deprivation therapy (ADT) for a set period of time or as part of your long-term prostate cancer treatment. Many men may take bone health and bone strength for granted.
Yes, prostate cancer can spread to the bones — in fact, it is one of the common locations for prostate cancer to spread. When it does so, it can weaken the bone and increase the risk of breaks, or fractures. Additionally, ADT, which is the mainstay of systemic therapy for patients with locally advanced and metastatic prostate cancer, will also weaken your bones. Other advanced prostate cancer treatments including steroids, novel hormonal therapies, and chemotherapy may also cause bone health problems.
Bone Health Assessments for Patients
There are several assessments that patients should receive before starting ADT and while on ADT. First, it is important to know your fracture risk. A fracture risk assessment can be easily done using the Fracture Risk Assessment Tool (FRAX) at the start of ADT.[1] It is important when you are calculating this score online to select “secondary osteoporosis” as a risk factor, which is a result of receiving ADT for your prostate cancer.
The FRAX score estimates your 10-year risk of hip fracture and major osteoporotic fractures (such as spine, shoulder, or wrist fractures). Patients starting androgen deprivation therapy (ADT), especially if it is expected to be long-term, should generally have a baseline dual-energy x-ray absorptiometry (DEXA) scan at the start of treatment or within a few months of starting.
Ongoing DEXA scans are recommended during ADT based on fracture risk. A DEXA scan measures bone mineral density, which tells your treatment team how strong or dense your bones are. The following table adapted from the NCCN prostate cancer guidelines summarizes the timing of DEXA scans throughout your prostate cancer journey while receiving ADT:
| Clinical Scenario | Recommendation |
|---|---|
| Baseline when starting ADT | A baseline DEXA scan is recommended for most patients starting ADT. In select patients with a low estimated fracture risk based on the FRAX risk assessment tool, a DEXA study does not have to be done |
| During ADT | Repeat DEXA scanning every 1–2 years, with the frequency guided by fracture risk as assessed using the FRAX tool |
| Patients receiving antiresorptive therapy (see below) | Repeat DEXA scanning at 12 months after starting this treatment to assess treatment response and ongoing fracture risk |
Making Your Bones Stronger
There are ways that you can make your bones stronger and protect from fractures while you are receiving ADT:
- All men who are taking ADT should take supplemental calcium and vitamin D. These are critical building blocks for the body to build and maintain bones. You can get these without a prescription from your local pharmacy, and you should take them daily. Patients should generally aim for 800-2,000 international units of vitamin D daily (to maintain a level of 30–50 ng/mL) and 1,000-1,200 mg of calcium per day from diet and/or supplements.
- Weight-bearing exercise is very important. When men lose muscle, the risk of falls increases and this increases the risk of bone fractures. This means an activity that improves strength and puts a (manageable) stress on the bones helps to keep them strong. Walking is a great start. Talk with your doctor first to see if more intense exercise may be helpful too.
- Smoking and excessive alcohol use can weaken bones, so avoiding smoking and large amounts of alcohol are also important.
- Use of antiresorptive (also called “bone-protecting”) medications may be recommended. These medications improve bone density and reduce the risk of fractures and other bone complications. Options include alendronate (Fosamax), denosumab (Prolia for treatment-related bone loss; Xgeva for advanced cancer involving the bones), and zoledronic acid (Reclast for bone loss; Zometa for advanced cancer involving the bones). These medications are used at different doses and schedules depending on your specific situation, so it is important to discuss with your doctor whether treatment is appropriate and which option is best for you.
The following table adapted from the NCCN prostate cancer guidelines summarizes how to optimize your bone health during your prostate cancer journey:
| Patient Population | Category | Intervention |
|---|---|---|
| All patients receiving ADT | Lifestyle modifications | • Weight-bearing exercise (≥30 minutes daily), balance training, and safe movement strategies to reduce fall risk • Limit alcohol consumption • Smoking cessation |
| Calcium and vitamin D supplementation | • Calcium intake of 1,000–1,200 mg daily, preferably from dietary sources with supplementation if needed • Maintain serum vitamin D3 levels of 30–50 ng/mL with supplementation as needed |
|
| Patients receiving ADT with treatment-related bone loss | Antiresorptive agents | • Alendronate 70 mg by mouth weekly, or • Denosumab 60 mg under the skin injection every 6 months, or • Zoledronic acid 5 mg via a vein every year |
| Patients with very advanced prostate cancer (ie. bone mCRPC) for prevention of symptomatic fractures | Antiresorptive agents | • Denosumab 120 mg under the skin injection every 4 weeks, or • Zoledronic acid 4 mg via a vein every 12 weeks |
Patients starting these medications may need a dental evaluation beforehand, as some treatments can affect jaw health.
Unfortunately, bone health is often inadvertently overlooked during treatment of advanced and metastatic prostate cancer, so it is important to have these conversations with your treatment team.
Key Takeaways
- Bone loss is common with ADT and increases fracture risk
- Regular monitoring with DEXA scans is important
- Calcium, vitamin D, and exercise help maintain bone strength
- Bone-protecting medications may be appropriate for some patients
References:
[1] University of Sheffield. FRAX® Fracture Risk Assessment Tool. https://www.fraxplus.org/