Lutetium-177 PSMA therapy

Lutetium-177 PSMA therapy is a targeted radiotherapy for advanced prostate cancer that has spread to other parts of the body. A radioactive medicine is injected into your bloodstream, where it seeks out and attaches to prostate cancer cells wherever they are, delivering radiation that destroys them while causing little damage to the healthy tissue nearby.

What conditions does it treat?

This treatment is for advanced, or metastatic, prostate cancer, where the cancer has spread from the prostate to other parts of the body, most often the bones. It's specifically used for metastatic castration-resistant prostate cancer, meaning the cancer keeps growing despite hormone treatment.

Your team may recommend it if:

• Blood tests and scans show your cancer is progressing
• Other treatments haven't been successful, including chemotherapy or newer hormonal therapies such as enzalutamide or abiraterone
• You're experiencing cancer-related pain, often in your bones
• Your cancer cells carry enough of a marker called PSMA, confirmed by a PET scan beforehand.

What are the benefits?

Clinical trials have shown that, if successful, this therapy can help improve:

• Your chance of survival
• How long the disease is controlled before it gets worse
• Cancer-related symptoms
• Your quality of life.

It works by reducing tumour size and helping stop tumours growing, and most people who have it see their symptoms and quality of life improve. In one major trial, people having this treatment had a longer period before their pain levels increased, alongside improved survival and quality of life, compared with standard care alone. Because the radiation dose is delivered directly to cancer cells wherever they are in the body, the rest of your body is exposed to very little radiation.

Is treatment tailored to me?

This is a ‘theranostic’ treatment, meaning it's closely paired with a matching diagnostic scan. Before starting, you'll have a PET scan using a different radioactive tracer, to check whether your cancer cells carry enough PSMA to respond to the therapy; only if they do will lutetium-177 PSMA be recommended.

Your treatment plan, including how many cycles you have and the gap between them, is tailored to you based on:

• Your general fitness
• How severe your condition is
• Whether you experience treatment-related side effects
• Whether you've had other prostate cancer treatments before.

What happens before treatment?

You'll meet a specialist doctor and nurse to talk through whether this treatment is right for you, with plenty of chance to ask questions. Nothing is decided on the spot: you'll be given time to think it over and discuss it with family or friends if you'd like to, and treatment only goes ahead once you've given your consent, usually at a later appointment.

• Most people have this as a day case, with no need to stay in hospital overnight.
• Make sure you've eaten and had something to drink before you arrive.
• Drinks and food are usually provided during your appointment, or you're welcome to bring your own.
• It's worth bringing something like a book to help pass the time afterwards.

What happens during treatment?

1. Your team goes through a checklist with you, talks through the therapy, and answers any questions. If you're happy to proceed, you'll sign a consent form.
2. A thin tube (a cannula) is placed into a vein in your arm or hand.
3. The lutetium-177 PSMA is injected through the cannula into your bloodstream. This takes only a few minutes.
4. The cannula is flushed and removed.
5. You'll then stay in the room alone for around 4 to 6 hours. This is because the treatment makes you temporarily radioactive, and staying in the room protects other people from unnecessary radiation exposure while your levels drop. You're free to eat, drink and move about during this time, with a toilet nearby for you to use.
6. Your radiation levels are checked regularly with a monitor, to work out when it's safe for you to go home, usually by late afternoon, though this varies from person to person.

What does recovery look like?

On the day

You'll go home the same day, once your radiation levels have dropped to a safe level. Because of the radioactive nature of the treatment, you won't be able to have someone stay with you during the appointment, so arrange for a lift home in advance; staff can contact them with an approximate time. Sometimes, a scan the following day checks how well the treatment has been taken up by the cancer cells, similar to a CT or PET scan, and you won't need to undress for it.

At home

A small amount of radiation stays in your body for a few days, so you'll be given written instructions to follow at home, covering things like limiting close contact with others, especially children and pregnant women, and hand washing and bathroom hygiene, since some of the radiation leaves your body in your urine and stools.

Most people have up to 6 cycles of treatment in total, roughly 6 to 8 weeks apart. How many cycles you have, and the exact gap between them, depends on your fitness, how severe your condition is, any side effects you experience, and any previous prostate cancer treatment. You'll be contacted around 10 days before each new cycle is due, to confirm the date and check you're well enough to go ahead, and you'll need a blood test after each cycle.

What are the risks and complications?

This treatment is generally well tolerated by most people, though as with any treatment, there are some possible side effects.

• Dry mouth, and sometimes dry eyes, loss of appetite, nausea and fatigue, since normal tissues such as the salivary glands also carry a small amount of PSMA.
• A temporary dip in blood counts in the first few weeks, usually not noticeable day to day but checked with blood tests; research suggests this can occasionally reach more serious levels, most often affecting red blood cells, white blood cells or platelets.
• If you had extensive cancer in your bones, the amount of healthy bone marrow may be reduced, which can mean needing a blood transfusion to help you recover.
• A small risk that radiation damage to healthy cells could lead to a new cancer developing in the future; your team believes the potential benefit of treatment outweighs this risk, and will discuss it with you.

Most side effects are temporary and settle without further treatment, often within a few days.