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.

Lu177 PRRT For Neuroendocrine Tumors (Nets)

Summary (10 sec read)

Peptide Receptor Radionuclide Therapy (PRRT) is a nuclear medicine treatment for Neuroendocrine Tumors (NETs) used worldwide. PRRT involves combining a cell-targeting protein, or peptide, with a radioactive material to create a radiopeptide. This radiopeptide is injected into the patient's bloodstream, where it targets NET cells that have somatostatin receptors, unlike healthy cells. The radiopeptide binds to these receptors and emits radiation to kill the tumor cells.

The treatment process involves creating a peptide that binds to tumor cell receptors, pairing it with a radioactive atom using a chelator, and injecting this radiopeptide into the bloodstream. The radiopeptide locates and binds to the NET cancer cells, delivering a lethal dose of radiation.

Patients typically undergo 4-6 PRRT sessions, spaced 2-3 months apart, as outpatient procedures. Clinical trials have demonstrated that PRRT can increase progression-free survival, improve quality of life, relieve symptoms, and reduce tumor size. While generally well-tolerated, PRRT can cause side effects such as nausea, vomiting, abdominal pain, and fatigue. Rare side effects include bone, liver, and kidney toxicity, and mild hair loss.

Nuclear Medicine, as a treatment protocol for Neuroendocrine Tumors (NETs) has been used in many countries across the globe for many a years.

PRRT or Peptide Receptor Radionuclide Therapy is a type of Nuclear Medicine Therapy in which a cell-targeting protein or peptide is combined with a small amount of radioactive material that created a special type of radiopharmaceutical known as a Radiopeptide. This radiopeptide is injected into a Neuroendocrine Tumor patient’s bloodstream.

Unlike healthy cells, the neuroendocrine tumor cells or NET cells have proteins on their cell surface. These proteins, also known as receptors, bind themselves to hormones, such as somatostatin. Peptide Receptor Radionuclide Therapy or PRRT with lutetium 177 dotatate or Lu177 targets these receptors with radiopeptides and deliver a high dose of radiation to the tumor cells.

How PRRT for NET works? – Method of Action

A peptide i.e. a group of amino acids is created that can bind to the receptors on the tumor cell’s surface.
This peptide is then paired with a radioactive atom using a chelator (a bonding agent).
This combination of the peptide and the radioactive material creates a radiopeptide.
This radiopeptide is injected into a Neurodendocrine Tumor (NET) patient’s bloodstream.
The radiopeptide finds the NET cancer cell’s somatostatin receptors and binds itself to them.
The radiopeptide emits radiation that kills the NET cancer cell.

Benefits of PRRT

Depending on the type of cancer being treated, patients may need to undergo up to 10 PRRT sessions. Usually, there would be around four-six sessions and these sessions are spaced two-three months apart. In most cases, this procedure is done as an outpatient procedure.

Several studies and clinical trials have shown that PRRT can…

Increase progression-free survival and in many cases likely survival.
Improve the quality of life.
Relieve symptoms.
Decrease tumor size.

While PRRT is generally well-tolerated, there occur some common side-effects, such as nausea, vomiting, abdominal pain and fatigue. Some very rare side-effects are bone, liver & kidney toxicity and mild hair loss.

Also Read: Which Patient can Benefit with PRRT

For more information on how PRRT can help, please call Dr. Ishita Sen, Director & Head, Department of Nuclear Medicine & Molecular Imaging, Fortis Memorial Research Institute (FMRI)on +91 9811 12 7080, or send an email to info@nuclearmedicinetherapy.in