If you or someone close to you has advanced prostate cancer, you may be hearing about newer treatments such as Actinium-225 PSMA therapy. This emerging approach uses targeted alpha radiation to deliver powerful treatment directly to PSMA-positive cancer cells, and researchers are studying whether it could help people whose cancer has become resistant to other therapies.
You should remember that Actinium-225 PSMA therapy is still emerging, with research continuing on its safety, dosage and long-term benefits. Your specialist can help you understand whether newer treatments could have a role alongside established prostate cancer treatments.
What Is Actinium-225 PSMA Therapy?
You may think of Actinium-225 PSMA therapy as a targeted treatment that carries radiation directly to prostate cancer cells. The PSMA-targeting molecule attaches to cancer cells, while Actinium-225 releases alpha particles that damage their DNA.
You receive the treatment through your bloodstream, allowing it to travel to PSMA-positive cancer cells throughout your body. Unlike external radiotherapy, you receive the radiation through a targeted carrier, which is why it is also called radioligand or targeted radionuclide therapy.
How Is Actinium-225 Different From Lutetium-177 PSMA Therapy?
You may notice that lutetium-177 uses beta radiation, while Actinium-225 uses alpha radiation. Alpha particles travel a much shorter distance but deliver more energy, causing severe DNA damage to nearby cancer cells.
You should know that this does not automatically mean fewer side effects. Your salivary glands and kidneys can also be affected, so researchers are studying how to destroy cancer cells while protecting healthy tissue.
Actinium-225 vs Lutetium-177 PSMA Therapy: Key Differences
| Feature | Actinium-225 PSMA Therapy | Lutetium-177 PSMA Therapy |
| Type of radiation | Uses alpha radiation with very high energy | Uses beta radiation with a longer travel distance |
| How it works | Delivers alpha particles to PSMA-positive cancer cells, causing severe DNA damage | Delivers beta radiation to PSMA-positive cancer cells to damage and kill tumour cells |
| Radiation range | Very short range, affecting cells close to where it binds | Longer range, allowing radiation to reach a wider area around the targeted cell |
| Current evidence | Promising early results, but long-term effectiveness is still being studied | More established evidence and approved use in selected patients |
| Typical use being studied | Mainly investigated for advanced or treatment-resistant prostate cancer, including after other PSMA therapies | Used for selected men with PSMA-positive metastatic castration-resistant prostate cancer |
| Potential advantage | May deliver stronger radiation damage to resistant cancer cells | Has more established clinical experience and treatment protocols |
| Main concerns | Long-term benefits, ideal dosing and side-effect management remain uncertain | Can cause side effects such as dry mouth, fatigue, kidney effects and blood-count changes |
| Effect on healthy tissue | Can affect PSMA-expressing tissues such as salivary glands | Can also affect salivary glands, kidneys and bone marrow |
| Future role | May become an option for selected patients if ongoing trials confirm benefits | Currently remains the more established PSMA radioligand therapy |
Why Are Researchers Interested in Alpha Radiation?
You may benefit from the high energy of alpha particles, which can cause severe DNA damage in prostate cancer cells. Their short travel distance may also help focus the treatment around PSMA-positive cancer cells.
You can receive PSMA-targeted therapy throughout your body, which may be useful when cancer has spread to multiple areas. However, researchers still need more evidence to know whether these potential benefits improve survival or quality of life.
How Does Actinium-225 PSMA Therapy Target Prostate Cancer Cells?
You may be eligible for this treatment if your prostate cancer cells produce enough PSMA. The targeting molecule travels through your bloodstream, attaches to PSMA-positive cancer cells and delivers Actinium-225 directly to the tumour.
You will usually have PSMA imaging, such as a PSMA PET/CT scan, before treatment to check whether your cancer has enough PSMA. This helps your doctor decide whether targeted therapy is suitable for you.
Who Might Benefit From Actinium-225 PSMA Therapy?
You may hear about Actinium-225 PSMA therapy mainly for men with metastatic castration-resistant prostate cancer (mCRPC). Doctors may consider Actinium-225 PSMA therapy when prostate cancer has progressed despite other treatments, particularly when the cancer continues to show PSMA expression.
You should know that research is still limited, so doctors cannot yet say exactly who benefits most. Researchers are studying whether you should receive Actinium-225 before or after lutetium-177 PSMA therapy and whether you could benefit at an earlier stage.
What Have Early Studies Shown?
You may find early research encouraging, as some men have experienced meaningful PSA reductions and tumour responses with Actinium-225 PSMA therapy. You may be especially interested if you have already received several treatments, including chemotherapy or lutetium-177 PSMA therapy.
You should remember that these studies are often small and use different treatment doses and response measures. You cannot yet know how much benefit comes specifically from Actinium-225, so larger clinical trials are needed before it can become a routine treatment.
Research Insight
Early studies suggest that Actinium-225 PSMA therapy may help some men with metastatic castration-resistant prostate cancer, including those whose cancer has progressed after several previous treatments. Some studies have reported PSA reductions and tumour responses, showing potential for this targeted alpha therapy.
However, current evidence mainly comes from small retrospective studies, so researchers still need larger clinical trials to understand the best dose, treatment timing and which patients are most likely to benefit. Actinium-225 remains an emerging therapy rather than a replacement for established PSMA treatments such as lutetium-177 PSMA therapy.
Could Actinium-225 Help Patients Resistant to Lutetium-177?
You may be interested in Actinium-225 if your cancer has stopped responding to lutetium-177 PSMA therapy. You may benefit from its different Type of radiation used damage, which researchers hope could overcome some treatment resistance.
You should know that the best treatment sequence is not yet established. Researchers are studying which patients respond, how long benefits last and whether you should receive Actinium-225 earlier in treatment.
What Are the Potential Advantages of Actinium-225?
You may benefit from the high-energy alpha radiation, which can cause extensive DNA damage over a very short distance. You may also receive treatment to cancer deposits in multiple parts of your body through PSMA targeting.
You should remember that these are potential advantages rather than proven benefits. Researchers still need to show whether Actinium-225 helps you live longer, reduces symptoms or improves your quality of life.
What Are the Possible Side Effects?
You may experience side effects such as dry mouth, kidney effects, reduced blood counts, fatigue or nausea. You may be more at risk of blood-count changes if you already have bone metastases or have received treatments that affect your bone marrow.
You should know that Actinium-225 can also affect healthy tissues, particularly the salivary glands. Researchers are studying safer doses and protective measures, while longer-term side effects continue to be assessed.
Why Can Actinium-225 Affect Salivary Glands?
You may develop dry mouth because your salivary glands naturally contain small amounts of PSMA. When Actinium-225 targets PSMA, some radiation can reach these healthy tissues and reduce saliva production.
You may notice effects on eating, speaking or dental health if the dryness is significant. Researchers are exploring better targeting, dosing and protective treatments to reduce these effects.
How Does Actinium-225 Compare With Standard Prostate Cancer Treatments?
You should not see Actinium-225 as a replacement for established prostate cancer treatments. If your cancer is localised, you may be offered surgery or radiotherapy, while advanced disease may require hormone therapy, chemotherapy or other systemic treatments.
You may be considered for Actinium-225 mainly when prostate cancer has spread and other treatments have been used. Researchers are still studying whether you could benefit more from Actinium-225 alone or as part of a combination treatment.
UK Guidance Note
In the UK, lutetium-177 PSMA radioligand therapy is an established treatment option for selected men with PSMA-positive metastatic castration-resistant prostate cancer. Actinium-225 PSMA therapy remains an emerging treatment and is currently being investigated through clinical studies and specialist programmes.
Your oncology team can advise whether approved treatments or clinical trials are most appropriate based on your cancer characteristics.
Is Actinium-225 Better Than Lutetium-177 PSMA Therapy?
You cannot say yet that Actinium-225 is better than lutetium-177 PSMA therapy. Lutetium-177 has stronger clinical evidence and established use, while Actinium-225 is still being studied.
You may eventually receive these treatments at different stages depending on your cancer and response. Researchers are studying whether Actinium-225 could be useful after lutetium-177 resistance or earlier in treatment.
What Clinical Trials Are Needed?
Before Actinium-225 becomes routine care, researchers need well-designed clinical trials to understand how effective and safe it is. These studies need to show whether you benefit from Actinium-225, which dose works best and whether you should receive it before or after lutetium-177.
You should also know that researchers are studying whether side effects can be reduced and whether you could benefit from combining treatments. Randomised trials are particularly important because they compare Actinium-225 with existing treatments, helping doctors understand whether any benefits come from the treatment itself.
Could Actinium-225 Be Used Earlier in Prostate Cancer?
You may currently hear about Actinium-225 mainly in advanced metastatic prostate cancer, but researchers are exploring whether it could be used earlier. Treating you before resistance develops could potentially target smaller amounts of cancer, although this approach needs careful testing.
You should know that a treatment suitable for you when other options are limited may not be appropriate earlier in the disease. Long-term side effects become more important when you could otherwise live for many years, so future trials must assess both cancer control and your quality of life.
How Does PSMA Imaging Help Select Patients?
PSMA PET/CT can help your doctor see where PSMA-positive prostate cancer is located and decide whether Actinium-225 therapy may be suitable for you. If your cancer has little PSMA expression, the treatment may be less likely to work because it relies on attaching to PSMA.
You should know that PSMA imaging is not perfect, as a visible signal does not guarantee that every cancer cell will respond. Some aggressive cancers may have mixed biology, with some cells producing little or no PSMA, making treatment selection more complex.
What Challenges Could Limit Widespread Use?
You may not have easy access to Actinium-225 PSMA therapy because Actinium-225 is rare and difficult to produce in large quantities. Treatment also requires strict manufacturing standards, specialised facilities, trained teams and careful handling of radioactive materials, which can affect cost and availability.
You should also know that doctors are still working out where Actinium-225 fits into your overall prostate cancer treatment. Even a promising therapy needs reliable supplies, safe treatment systems and stronger evidence before it can become widely available.
What Does the Future of PSMA Therapy Look Like?
You may see PSMA therapy becoming more personalised, with your tumour biology, PSMA imaging, previous treatment response and genetic information helping doctors choose the right approach. Actinium-225 is one part of this evolving field, alongside improved PSMA-targeting treatments and combination therapies.
You should know that the goal is not simply to give you stronger radiation, but to find the right treatment for you at the right stage of disease. If research confirms its benefits, alpha therapy could become an important option for people with advanced prostate cancer.
Should Patients Ask About Actinium-225 Now?
- Actinium-225 PSMA therapy is still an emerging treatment and is mainly being studied for advanced prostate cancer.
- Your suitability depends on factors such as PSMA expression, previous treatments, cancer stage and overall health.
- PSMA PET/CT imaging can help doctors identify whether your cancer may respond to this targeted approach.
- Early studies show promising responses in some men, but larger clinical trials are needed to confirm long-term benefits.
- Actinium-225 may cause side effects because healthy tissues, especially salivary glands, can also receive radiation exposure.
- It is not currently considered a replacement for established treatments such as lutetium-177 PSMA therapy.
- Your oncology team can help you understand whether clinical trials or specialist programmes may be appropriate for your situation.
What Questions Should You Ask About New PSMA Treatments?
If Actinium-225 or another advanced PSMA treatment is being discussed, you can ask why it is being considered, whether it is approved or part of a clinical trial, and how it compares with lutetium-177 PSMA therapy. You may also want to ask about the possible benefits, side effects and how your doctor will know whether the treatment is working.
You should also ask what other treatment options remain available to you. Understanding why a treatment is recommended can help you feel more involved in your care, especially when decisions depend on several factors rather than one test result.
Myth vs Fact
| Myth | Fact |
| Actinium-225 is already replacing lutetium-177 PSMA therapy. | No. It is still being studied and its best role is not yet established. |
| Stronger radiation automatically means better treatment. | No. The right treatment depends on cancer biology, PSMA expression and overall health. |
| A positive PSMA PET scan guarantees treatment success. | No. PSMA uptake helps selection but does not guarantee response. |
| Actinium-225 only affects cancer cells. | No. Healthy tissues such as salivary glands can also receive radiation exposure. |
| Actinium-225 can cure all advanced prostate cancer. | No. It is a promising treatment being investigated mainly for advanced disease. |
Key Takeaways
- Actinium-225 PSMA therapy is an emerging form of targeted alpha radiation treatment for prostate cancer.
- It uses PSMA targeting to deliver radiation directly to cancer cells.
- Alpha particles cause powerful DNA damage but may also affect healthy PSMA-expressing tissues.
- Early studies show promise, particularly in advanced treatment-resistant prostate cancer.
- Actinium-225 is not yet proven superior to lutetium-177 PSMA therapy.
- PSMA PET imaging helps identify patients who may be more suitable for treatment.
- Side effects can include dry mouth, kidney effects, fatigue and low blood counts.
- Larger clinical trials are needed before routine use becomes widespread.
Frequently Asked Questions
1. What is Actinium-225 PSMA therapy?
Actinium-225 PSMA therapy is a targeted radioligand treatment that uses a PSMA-targeting molecule to deliver Actinium-225 radiation directly to PSMA-positive prostate cancer cells.
2. How does Actinium-225 PSMA therapy work?
The treatment travels through your bloodstream and attaches to prostate cancer cells that produce PSMA. Actinium-225 then releases high-energy alpha particles that damage the DNA of nearby cancer cells.
3. How is Actinium-225 different from Lutetium-177 PSMA therapy?
Lutetium-177 uses beta radiation, while Actinium-225 uses alpha radiation. Alpha particles travel a shorter distance but deliver more energy, potentially causing extensive DNA damage to cancer cells.
4. Who might benefit from Actinium-225 PSMA therapy?
You may hear about Actinium-225 mainly for people with metastatic castration-resistant prostate cancer, particularly when the disease has progressed despite other treatments. Your suitability depends on factors such as PSMA expression and previous treatment.
5. Can Actinium-225 help if Lutetium-177 PSMA therapy stops working?
It may be an option for some people whose cancer has become resistant to Lutetium-177. However, researchers are still studying which patients benefit and the best sequence for using these treatments.
6. What are the possible side effects of Actinium-225 PSMA therapy?
You may experience dry mouth, fatigue, nausea, reduced blood counts or kidney effects. The salivary glands can be particularly affected because they naturally contain small amounts of PSMA.
7. How does PSMA imaging help before Actinium-225 treatment?
A PSMA PET/CT scan can help your doctor identify PSMA-positive prostate cancer and assess whether targeted therapy may be suitable for you. However, having PSMA uptake does not guarantee that every cancer cell will respond.
8. Is Actinium-225 better than Lutetium-177 PSMA therapy?
You cannot say yet that Actinium-225 is better. Lutetium-177 has stronger clinical evidence and established use, while Actinium-225 is still being investigated in clinical studies.
9. Is Actinium-225 PSMA therapy approved as a routine treatment?
Actinium-225 PSMA therapy is still an emerging treatment, and research is continuing into its safety, dosage, effectiveness and long-term benefits. Depending on where you live and your circumstances, you may encounter it mainly through clinical trials or specialised treatment programmes.
10. Should you ask your doctor about Actinium-225 PSMA therapy?
If you have advanced prostate cancer, you can ask your oncology team whether Actinium-225 clinical trials or treatment options may be suitable for you. Your doctor can explain how it compares with established treatments, including Lutetium-177 PSMA therapy, and discuss the potential benefits and uncertainties.
Final Thoughts: The Future of Actinium-225 PSMA Therapy
Actinium-225 PSMA therapy could become an important option for some people with advanced prostate cancer, particularly when other treatments are no longer working. However, you should remember that it is still an emerging treatment, and researchers are continuing to study its benefits, risks and place in prostate cancer care.
If you are exploring advanced prostate cancer treatment options, our team at Prostate Clinic London can help you understand the available approaches and discuss which treatments may be suitable for your situation.
References:
- Herrmann, K. et al. (2021) ‘Radioligand therapy in prostate cancer: Current status and future perspectives’, European Journal of Nuclear Medicine and Molecular Imaging, 48, pp. 4150–4165. Available at: https://pubmed.ncbi.nlm.nih.gov/34169378/
- Sathekge, M. et al. (2022) ‘Actinium-225-PSMA radioligand therapy of metastatic castration-resistant prostate cancer: A systematic review’, European Journal of Nuclear Medicine and Molecular Imaging, 49, pp. 3037–3048. Available at: https://pubmed.ncbi.nlm.nih.gov/35192218/
- Kratochwil, C. et al. (2018) ‘Targeted alpha therapy of metastatic castration-resistant prostate cancer with 225Ac-PSMA-617’, Journal of Nuclear Medicine, 59(5), pp. 795–801. Available at: https://pubmed.ncbi.nlm.nih.gov/29301910/
- Sartor, O. et al. (2021) ‘Lutetium-177–PSMA-617 for metastatic castration-resistant prostate cancer’, New England Journal of Medicine, 385, pp. 1091–1103. Available at: https://pubmed.ncbi.nlm.nih.gov/34161051/
- Herrmann, K. et al. (2025) ‘Alpha-emitting radioligand therapy with actinium-225 PSMA-targeted agents in metastatic prostate cancer: Current evidence and future directions’, European Journal of Nuclear Medicine and Molecular Imaging. Available at: https://pubmed.ncbi.nlm.nih.gov/