Bone-targeted radionuclide therapy is a Nuclear Medicine treatment that delivers radiation to areas of increased bone activity caused by cancer. A radiopharmaceutical is administered through a vein and travels through the bloodstream to areas where bone is actively responding to metastatic disease.
Once concentrated at these sites, the radionuclide releases radiation over a short distance, damaging nearby cancer cells while limiting exposure to much of the surrounding healthy tissue. Because the treatment circulates throughout the body, it can reach multiple bone metastases during the same treatment session.
Different bone-targeted radiopharmaceuticals have different purposes. Beta-emitting agents such as strontium-89 or samarium-153 may be used primarily to relieve pain from multiple bone metastases. Radium-223 is an alpha-emitting treatment used for appropriately selected patients with metastatic castration-resistant prostate cancer involving the bones. These agents are not interchangeable, and availability may vary.
- Painful bone metastases affecting multiple sites
- Bone pain that is not adequately controlled with medicines or that has returned after external radiation therapy
- Multiple painful bone metastases that cannot all be treated conveniently with local radiation therapy
- Osteoblastic or bone-forming metastases visible on bone imaging
- Prostate cancer that has spread predominantly to the bones
- Breast cancer with multiple painful bone metastases in selected circumstances
- Selected other cancers producing bone metastases that take up the proposed radiopharmaceutical
- Metastatic castration-resistant prostate cancer with symptomatic bone metastases when radium-223 is clinically appropriate
- Adequate bone-marrow function to tolerate the planned treatment
- Adequate kidney function for radiopharmaceuticals that are cleared through the urinary system
- A need for systemic treatment of pain arising from several skeletal sites
How Bone-Targeted Radionuclide Therapy Is Performed
Before Treatment
The Nuclear Medicine physician reviews the cancer diagnosis, symptoms, imaging, previous treatments and medical history.
A bone scan, PET-CT, CT, MRI or other imaging is reviewed to confirm the extent and pattern of bone involvement.
The team determines whether the bone metastases are likely to take up the proposed radiopharmaceutical.
Blood tests are performed to assess hemoglobin, white blood cells and platelets.
Kidney and liver function may be assessed according to the radiopharmaceutical being considered.
The patient’s bone-marrow reserve is evaluated, particularly after previous chemotherapy or extensive radiation therapy.
Current cancer medicines, blood-thinning medicines, supplements and other treatments are reviewed.
Recent chemotherapy or external radiation therapy may affect the timing of treatment.
Pregnancy and breastfeeding must be discussed because radioactive material is used.
Patients who may conceive or father a child receive specific advice about contraception.
Hydration and eating instructions are provided according to the planned radiopharmaceutical.
The expected treatment goal is discussed, including whether therapy is intended primarily to relieve pain or to treat eligible prostate cancer involving bone.
The number and timing of planned administrations, possible side effects and radiation-safety precautions are explained.
Pain medicines are reviewed because symptom relief is not immediate and existing medicines may still be needed.
During Treatment
The patient attends a designated Nuclear Medicine treatment area, usually as a day-care patient.
An intravenous line is placed in the arm.
The prescribed radiopharmaceutical is administered slowly through the intravenous line.
The administration itself usually takes only a few minutes.
The radiopharmaceutical travels through the bloodstream and accumulates in areas of increased bone turnover.
Radiation emitted at these sites damages nearby cancer cells.
The patient is monitored for any immediate reaction.
Most patients do not feel the radiation being delivered.
Some treatments are administered as a single dose, while others are delivered as a planned series of injections separated by several weeks.
The intravenous line is removed after administration and monitoring.
Radiation levels and discharge requirements are assessed according to the radionuclide used.
After Treatment
Most patients can return home on the same day.
Hydration may be encouraged to help the body remove unbound radiopharmaceutical.
Patients are advised to empty their bladder regularly and follow careful toilet hygiene.
Temporary radiation-safety precautions are provided according to the radionuclide used.
Instructions may include careful handling of urine, blood or other bodily fluids for a specified period.
Close contacts or caregivers may be advised to use gloves if cleaning contaminated material.
Existing pain medicines should be continued or adjusted only under medical guidance.
A temporary increase in bone pain, known as a pain flare, may occur before improvement begins.
Pain relief may develop gradually over one or more weeks.
Blood tests are repeated to monitor haemoglobin, white blood cells and platelets.
For treatments delivered in cycles, blood counts and overall condition are assessed before each subsequent dose.
Follow-up includes review of pain, mobility, medicine requirements, side effects and quality of life.
Cancer-specific blood tests and imaging may be arranged according to the underlying disease.
Additional radionuclide therapy, external radiation therapy, systemic therapy or another treatment may be recommended according to the response.
Potential Benefits of Bone-Targeted Radionuclide Therapy
- Treatment delivered to multiple sites of active bone disease through a single intravenous administration
- Relief of pain caused by widespread bone metastases
- Reduced need for pain medicines in some patients
- Improvement in mobility, sleep or daily functioning when pain is reduced
- Treatment of skeletal sites that may not be suitable for separate local procedures
- A systemic option when pain arises from several areas of bone
- Targeting based on increased bone activity around the metastases
- Limited radiation range around the targeted bone sites
- The ability to repeat selected treatments when clinically appropriate
- Integration with pain medicines, systemic cancer treatment, external radiation therapy and supportive care
- Treatment of eligible prostate cancer involving bone with radium-223
- Delay of certain symptomatic skeletal complications and a survival benefit with radium-223 in appropriately selected patients with metastatic castration-resistant prostate cancer
Side Effects of Bone-Targeted Radionuclide Therapy
- Temporary increase in bone pain after treatment
- Tiredness or weakness
- Nausea or vomiting
- Diarrhoea, particularly with radium-223
- Reduced appetite
- Mild swelling of the legs or feet
- Reduction in red blood cells, causing anaemia
- Reduction in white blood cells, increasing infection risk
- Reduction in platelets, increasing bleeding or bruising risk
- Temporary or prolonged bone-marrow suppression
- Dehydration if vomiting or diarrhoea occurs
- Temporary changes in kidney function with some radiopharmaceuticals
- Incomplete pain relief
- Pain returning after an initial response
- Continued cancer progression outside the treated bone sites
- Rare severe reduction in blood-cell counts requiring transfusion or other treatment
- Rare longer-term bone-marrow disorders after cumulative radiation exposure
