What is Lu PSMA (Lutetium-Prostate Specific Membrane Antigen) Therapy?

Lu177 PSMA Therapy is a treatment for patients with prostate cancer, especially those who have become refractory to conventional therapy. Lutetium PSMA therapy helps to slow down the growth of the cancer cells, reduce the size of the tumours and most importantly improve the quality of life of the patients by reducing the pain caused by the cancer.

Many prostate cancers, in particular those that have spread or become resistant to hormonal therapies, express a unique receptor on their cell surface called Prostate Specific Membrane Antigen (PSMA). When Prostate Cancer metastasizes i.e. spreads to other parts of the body, the PSMA receptor is expressed over the sites of metastases as well.

How does Lu PSMA Therapy Work?

Lutetium-177 is a radioactive substance that emits beta radiation, a destructive kind of radiation. Lutetium-177 is bound to a small peptide which attaches to the PSMA receptor expressed on the cancer cell surface. The Lutetium 177 – PSMA complex, thus attached to the prostate cancer cell, then emits killing radiation causing cell death of the cancer cell. Since the penetration of the emitted beta particle is very small, the surrounding normal cells are spared.

How is the Therapy Done?

Lu177 PSMA is administered intravenously. The patient is admitted to the hospital for 24 hours. A kidney function scan called a MAG3/EC scan is done prior to the administration of the Lu177 PSMA.

What are the Side Effects of Lu PSMA Therapy?

Lu177 PSMA is well tolerated. The most common side effects are a slightly dry mouth, fatigue and nausea. There may also be a slight fall in the white blood cells and platelets about 2 – 3 weeks after the Lu177 PSMA administration.

What is the Response Rate With Lu PSMA Therapy?

The response rates of Lu177 PSMA depend on the tumour biology of prostate cancer, the initial Gleason Score, the extent of disease and the responses to prior therapies. Typically, more than 70% of patients demonstrate a reduction in S. PSA and a shrinkage of tumours following Lu177 PSMA therapy.

When would the doctor consider using this Therapy?

Lu PSMA Therapy is a very specific therapy and is used for managing metastatic Prostate Cancer or when Prostate Cancer is no longer responsive to other types of treatment.

What are the Treatment Schedules with Lu PSMA Therapy?

Most patients undergo three-four treatment cycles at intervals of 8-12 weeks. The number of cycles and the interim duration may vary between individuals depending on the response and interim assessments.

Why should I choose the nuclear medicine therapy center at Fortis Memorial & Research Institute (FMRI), Gurugram (Haryana, India)?

The Nuclear Medicine Therapy Centre at FMRI was one of the first institutes to offer Radio-ligand Therapy with Lu PSMA, and today, the center receives patients from the country and from across the world.

Combating Xerostomia: Botox Shows Promise in Actinium-225 Therapy

Summary (10 sec read)

This article explores the potential of Botox injections in preventing xerostomia (dry mouth), a common side effect of Actinium-225 cancer therapy. Research suggests Botox may offer a promising solution for improving the quality of life for cancer patients undergoing this treatment. Imagine struggling to enjoy a simple meal, having trouble speaking clearly, or constantly feeling parched. These are just some of the daily challenges faced by individuals living with xerostomia, or severe dry mouth.

Unfortunately, individuals battling cancer can face an increased risk of developing xerostomia as a side effect of certain treatments, including Actinium-225 (Ac-225) therapy. While Ac-225 therapy shows great promise in targeting cancer cells, it can inadvertently damage the salivary glands, leading to decreased saliva production and the uncomfortable symptoms of dry mouth.

However, there's hope on the horizon. A 2021 pilot study published by Y. Baum et al. investigated the use of Botox injections to prevent xerostomia in patients undergoing Ac-225 therapy. The study's results were encouraging, showing a significant reduction in the severity of dry mouth in patients who received Botox injections before their treatment. Botox, primarily known for its cosmetic applications, works by temporarily reducing saliva production. In the context of Ac-225 therapy, this reduction helps minimize the uptake of radioactive isotopes by the salivary glands, thus protecting them from radiation damage and lowering the chances of developing xerostomia.

Mechanism Summary:

Neurotoxin Action: Botox blocks acetylcholine, preventing salivary stimulation.
Reduced Radiation Absorption: With reduced gland activity, there is less uptake of radioactive isotopes like Actinium-225.
Preservation of Salivary Gland Function: Temporary inhibition reduces radiation-induced fibrosis and maintains long-term gland function.

In a 2021 pilot study published by Y. Baum et al. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9693763/], researchers investigated the efficacy of Botox injections in preventing xerostomia in patients undergoing Ac-225 PSMA therapy. The study involved a small cohort of 10 patients, each receiving Botox injections directly into the parotid and submandibular glands before the administration of Actinium-225 radiopharmaceuticals.

The results demonstrated a significant reduction in the severity of xerostomia, with the following key findings:

60% of patients reported no or mild dry mouth symptoms post-treatment, compared to a historical control group where 90% of patients reported moderate to severe xerostomia.
MRI and scintigraphy of the salivary glands showed reduced uptake of the radiopharmaceuticals in Botox-treated patients.
Long-term follow-up (6 months post-treatment) indicated that salivary function in Botox-treated patients returned to near-baseline levels, suggesting that the protective effect was temporary and did not cause permanent glandular dysfunction.

If you are planning your Actinium 225 or Pluvicto/Lutetium 177 therapy, do discuss these points with Dr. Ishita B Sen, our centre has a very advanced Plastic & Reconstructive Surgery department headed by Additional Director, Plastic and Reconstructive Surgery Dr Rashmi Taneja who will be willing to guide you on the benefits of Botox for prevention of Xerostomia post Ac 225 and Lu 177 therapy.

Additional Resources:

National Cancer Institute: Xerostomia [https://www.ncbi.nlm.nih.gov/books/NBK545287/]

Also Read

Medical Imaging: Shedding Light on Cancer Diagnosis and Treatment

Alpha Emitters Are 5 Times More Potent Than Beta Emitters By Dr. Ishita B. Sen

Frequently Asked Questions

What is xerostomia?

Xerostomia, commonly known as dry mouth, is a condition where the salivary glands do not produce enough saliva to keep the mouth moist. It can cause discomfort, difficulty in speaking, eating, and an increased risk of oral infections.
Why does xerostomia occur during Actinium-225 therapy?

Actinium-225 (Ac-225) therapy, while effective in targeting cancer cells, can inadvertently damage the salivary glands, leading to reduced saliva production and xerostomia. The radiation exposure from the therapy can cause fibrosis or scarring of the glands, reducing their function.
How can Botox help in preventing xerostomia during Ac-225 therapy?

Botox injections work by temporarily reducing salivary gland activity, which decreases the uptake of radioactive isotopes like Actinium-225 by the glands. This protects the glands from radiation damage, helping to prevent the onset of xerostomia.
Is Botox commonly used to treat xerostomia caused by cancer treatments?

While Botox is more commonly known for its cosmetic applications, its potential to treat xerostomia in patients undergoing nuclear medicine therapies like Ac-225 is gaining attention. A pilot study has shown promising results in reducing dry mouth symptoms.
What were the results of the 2021 pilot study involving Botox and Ac-225 therapy?

The 2021 study by Y. Baum et al. demonstrated that 60% of patients who received Botox injections before Ac-225 therapy reported no or mild xerostomia, compared to 90% of patients in a historical control group who reported moderate to severe symptoms. Additionally, MRI and scintigraphy showed reduced radiopharmaceutical uptake in the treated patients' salivary glands.
How long do the effects of Botox last for preventing xerostomia?

According to the study, Botox injections provided temporary protection to the salivary glands during Ac-225 therapy, with most patients’ salivary function returning to near-normal levels within six months of treatment.
Can Botox cause permanent damage to the salivary glands?

No, Botox does not cause permanent damage to the salivary glands. The effects are temporary, allowing the glands to return to their normal function after a period of time.
Should I consider Botox if I am undergoing Ac-225 or Lutetium-177 (Pluvicto) therapy?

If you are concerned about xerostomia during Ac-225 or Lutetium-177 therapy, it's a good idea to discuss Botox injections with your healthcare team. Specialists like Dr. Ishita B Sen and Dr. Rashmi Taneja may offer guidance on whether Botox is appropriate for your treatment plan.
Are there any risks associated with using Botox for xerostomia prevention?

As with any medical procedure, there are some risks associated with Botox injections, including localized discomfort or infection at the injection site. However, the procedure is generally considered safe when performed by a qualified healthcare provider.

Consult Dr Ishita B Sen

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