Why Bone Health Matters Now
If you have metastatic castration-resistant prostate cancer (mCRPC) and are considering Lu-177 PSMA therapy, your bones face pressure from two sources. Bone metastases develop in up to 90% of men who reach the castration-resistant stage of prostate cancer. Androgen deprivation therapy, or ADT, the hormone therapy most men with this diagnosis receive, also weakens bones over time in areas with no cancer. Both problems can happen at the same time and increase your fracture risk.
This article explains what happens to your skeleton during Lu-177 PSMA treatment, how the therapy affects bone disease, and what steps you and your care team can take to protect your bones before, during, and after infusion cycles.
Two Bone Problems You May Already Have
Bone disease in mCRPC has two distinct causes. They often overlap but require different approaches.
Bone Metastases
When prostate cancer spreads to bone, it disrupts the normal cycle of bone renewal. Some cancer deposits cause new bone to form in weak, abnormal patterns. Others cause bone to break down faster than new bone replaces it. Either way, the affected bone becomes fragile and can fracture from a minor fall or bump. These fractures are called pathological fractures and can cause severe pain, spinal cord compression, and loss of mobility.
ADT-Induced Bone Loss
ADT lowers testosterone, which bones need to stay dense. When testosterone drops, bones lose mineral density faster. Men on ADT have a higher risk of osteoporosis and fractures, even in parts of the skeleton with no tumor. The Prostate Cancer Foundation reports that prostate cancer survivors who received ADT had a 19% fracture rate, compared to 13% in those who did not receive ADT, over five years. If you are on ADT and starting Lu-177 PSMA treatment, you face both risks at once.
How Lu-177 PSMA Therapy Affects Your Skeleton
Lu-177 PSMA therapy delivers beta radiation to prostate cancer cells that carry the PSMA protein. Many of these cells live inside bone metastases. The therapy destroys tumor cells but does not rebuild bone or reverse osteoporosis. It differs from radium-223, which is approved to treat bone metastases in prostate cancer.
Reducing the tumor burden inside bone lesions can slow damage to bone structure. In the VISION trial, the large phase 3 study that led to FDA approval of 177Lu-PSMA-617, researchers tracked time to first symptomatic skeletal event as a key measure. According to data from the VISION study, men treated with 177Lu-PSMA-617 plus standard care had a longer time to first symptomatic skeletal event compared to those on standard care alone. A symptomatic skeletal event includes fractures, spinal cord compression, and the need for bone surgery or radiation. Delaying these events helps protect daily function and quality of life.
However, Lu-177 PSMA therapy does not rebuild bone or address osteoporosis from ADT. Protecting bone requires separate steps taken alongside your radioligand therapy cycles.
ADT Continues During Lu-177 PSMA Treatment
Most men receiving Lu-177 PSMA therapy stay on ADT throughout treatment. This means the bone loss from low testosterone continues during your infusion cycles. Lu-177 PSMA therapy does not change this. Without bone-protective measures in place, bone mineral density may decline during treatment.
The Urology Care Foundation says keeping bones strong during prostate cancer treatment takes deliberate steps: regular bone density monitoring, appropriate supplementation, and in some cases prescription medication. You and your care team must plan these steps explicitly, ideally before your first infusion.
Bone-Protective Medications: What the Evidence Shows
Two types of medication protect bones in men with mCRPC: bisphosphonates such as zoledronic acid and denosumab, a biologic therapy that blocks a protein called RANK ligand. Both slow bone loss from cancer and ADT. Both have been studied in large clinical trials with mCRPC patients who have bone metastases.
The National Cancer Institute reports that denosumab reduces the risk of fractures and other skeletal-related events in men with castration-resistant metastatic prostate cancer. In a large randomized clinical trial, denosumab delayed time to first skeletal-related event by a median of 3.6 months longer than zoledronic acid: 20.7 months versus 17.1 months. Both medications are standard options in this setting.
Neither denosumab nor zoledronic acid works for every patient. Both carry potential side effects. Denosumab can cause low calcium levels. Both drugs carry a small risk of osteonecrosis of the jaw, a condition where part of the jawbone fails to heal properly, usually after a dental procedure. Your care team will check your kidney function, calcium levels, and dental health before recommending one. Schedule a dental check-up before starting either medication.
Talk with your oncologist about both bone threats: bone metastases and ADT-related bone loss. The right dose and type of bone-protective medication may differ depending on which problem you need to treat. This distinction matters.
Lifestyle Steps That Support Bone Strength During Treatment
Medication is one tool. Several lifestyle approaches can help slow bone loss and lower fracture risk during Lu-177 PSMA treatment. While not a substitute for medical care, evidence shows they add benefit when combined with medical treatment.
- Calcium and vitamin D supplementation. Men on ADT need adequate amounts of both. Vitamin D helps your body absorb calcium and supports bone cell activity. Your care team can check your blood levels and recommend the right supplementation for you. Continue supplementation throughout your entire ADT period, not just when you start it.
- Weight-bearing and resistance exercise. Walking, resistance training, and other weight-bearing activities build bone-forming cells and help maintain density. Exercise also reduces fall risk by improving balance and muscle strength. Even modest, consistent activity makes a difference. Ask your care team before starting or changing your exercise routine, especially if you have bone metastases in the spine, hips, or pelvis.
- Fall prevention at home. Fragile bones mean that falls can cause serious fractures. Remove loose rugs and trip hazards, add grab bars in the shower and by the toilet, and improve lighting in hallways to reduce fracture risk at home.
- Reducing alcohol and not smoking. Both accelerate bone loss. Cutting back on alcohol and quitting smoking support bone health and treatment tolerance.
- Dental care before bone-protective medications. If you will take denosumab or a bisphosphonate, have a thorough dental check-up before starting. This reduces the risk of osteonecrosis of the jaw by addressing any infections or necessary procedures first.
For more information on approaches that complement Lu-177 PSMA treatment, see our guide to integrative therapies and lifestyle changes that can support Lu-177 PSMA treatment in men with PSMA-positive prostate cancer.
Getting a DEXA Scan: Why Baseline Bone Density Matters
A DEXA scan, short for dual-energy X-ray absorptiometry, is the standard test to measure bone mineral density. It differs from a nuclear medicine bone scan used to detect metastases. A DEXA scan measures how dense your bones are, usually at the hip and lumbar spine. The test is painless, quick, and uses a very small dose of radiation. It typically takes 10 to 20 minutes.
A comprehensive bone health management review states that men starting or already on ADT should have a baseline DEXA scan to check for osteoporosis or reduced bone density. If you have been on ADT for more than a few months and have never had one, ask your oncologist or primary care provider to arrange it. The result tells your team whether you need bone-protective medication and how soon.
The FRAX score is often used with DEXA results. It estimates your 10-year risk of a major osteoporotic fracture by considering your age, body weight, prior fractures, family history, and whether you are on ADT. Ask your oncologist if a FRAX score has been calculated for you. If not, request one. It takes only a few minutes and can guide treatment decisions.
Bone Pain During Treatment: What to Watch For and Report
Report new or worsening bone pain during or after a Lu-177 PSMA infusion to your care team right away. Some patients have a brief flare of bone pain in the first few days after an infusion, usually from the treatment reaching active disease sites. However, sudden severe pain, especially in the back or near the spine, requires prompt medical evaluation. Other urgent symptoms include new numbness or weakness in the legs, difficulty controlling the bladder or bowel, and pain after a minor bump or fall. These can signal a fracture, spinal cord compression, or another skeletal emergency. Do not wait for your next appointment if any develop.
If bone pain from metastases concerns you, there is growing evidence that Lu-177 PSMA therapy may provide pain relief. Read more in our article on whether Lu-177 PSMA therapy can help with bone metastases pain.
A Practical Bone Health Checklist for Patients Starting Lu-177 PSMA
Here are the key bone health steps to discuss with your care team before and during treatment:
- Ask whether you have had a DEXA scan and what the result showed.
- Ask whether a FRAX fracture risk score has been calculated for you.
- Ask whether a bone-protective medication such as denosumab or a bisphosphonate is right for you and whether you are already taking one.
- Make sure your calcium and vitamin D intake is adequate and ask about supplementation based on your blood levels.
- Schedule a dental check-up before starting any bone-protective medication.
- Ask a physical therapist or exercise specialist about safe weight-bearing activity given your bone metastases location.
- Report any new or worsening bone pain right away. Do not wait for your next routine visit.
- Review fall hazards in your home and consider occupational therapy if your mobility or balance is affected.
Bone health matters during mCRPC treatment. It affects your quality of life, your ability to stay mobile and independent, and your ability to continue treatment. Protecting your skeleton gives you the best foundation to move through treatment as safely as possible.
For a complete picture of side effects from Lu-177 PSMA therapy and how medical teams manage them, see our detailed guide on the real-world side effects of Lu-177 PSMA therapy for metastatic castration-resistant prostate cancer.
When to Talk to Your Doctor
Talk to your oncologist or care team if you have not had a DEXA scan since starting ADT, if you have had a prior bone fracture or significant fall, if you are experiencing new or worsening bone pain, or if bone-protective medication has not been discussed with you. These conversations matter before your first infusion and at regular intervals throughout treatment.
This article is for general information and is not a substitute for medical advice. Always consult your oncologist or care team about your specific situation.
Frequently asked questions
Does Lu-177 PSMA therapy directly damage or weaken my bones?
Lu-177 PSMA therapy does not directly target bone tissue the way radium-223 does. It targets prostate cancer cells that carry the PSMA protein, many of which are lodged in bone metastases. By reducing tumor activity in those lesions, it may slow the damage those cells were causing to bone structure. However, it does not reverse osteoporosis or rebuild the bone mineral density lost through androgen deprivation therapy. Separate bone-protective measures are needed to address those risks alongside your Lu-177 PSMA treatment.
Should I be on denosumab or a bisphosphonate while receiving Lu-177 PSMA therapy?
Many oncologists recommend a bone-protective medication for mCRPC patients with bone metastases, regardless of whether they are receiving Lu-177 PSMA therapy. The right choice depends on your bone density results, kidney function, dental health, calcium levels, and overall medical picture. Both denosumab and bisphosphonates such as zoledronic acid have been studied in mCRPC and may reduce the risk of fractures and other skeletal complications. Ask your oncologist specifically whether you have been assessed for bone protection and whether it is appropriate for you — this conversation is worth having explicitly before your first infusion.
What is a DEXA scan and do I need one before starting Lu-177 PSMA therapy?
A DEXA scan measures bone mineral density, usually at the hip and spine. It is different from the bone scan used to detect metastases — a DEXA scan assesses structural strength, not cancer spread. It is a quick, painless test that takes about 10 to 20 minutes and uses very low radiation. Guidelines recommend that men on androgen deprivation therapy for prostate cancer have a baseline DEXA scan to detect osteoporosis or low bone density. If you have been on ADT for more than a few months and have never had one, ask your oncologist or primary care provider to arrange it as part of your pre-treatment assessment.
Is it safe to exercise if I have bone metastases and am receiving Lu-177 PSMA therapy?
Light to moderate weight-bearing exercise — such as walking — can help maintain bone density, muscle strength, and balance, and may reduce fall risk. However, if you have metastases in load-bearing bones such as the spine, hips, femurs, or pelvis, some types of exercise may carry a fracture risk. A physical therapist with oncology experience can help design a safe, personalized activity program for your specific metastasis locations. Always let your care team know about your exercise plans before making any significant changes, especially during or just after a treatment cycle.
What bone pain symptoms during Lu-177 PSMA treatment should prompt an urgent call to my doctor?
A brief, mild flare of bone pain in the days after an infusion is sometimes reported and usually resolves on its own. However, sudden severe pain — especially in the spine or back — needs prompt medical evaluation and should not be waited out. Other symptoms requiring urgent contact include new numbness or weakness in the legs, difficulty controlling the bladder or bowel, and pain following a minor bump or fall. These could indicate a fracture, spinal cord compression, or another skeletal emergency. Always call your care team the same day if any of these develop rather than waiting for a scheduled appointment.