WHAT IS PRRT AND HOW DOES IT WORK?
PRRT - Peptide Receptor Radionuclide Therapy, also known as Radioisotope Therapy, is a molecular therapy that is used to treat a specific type of cancer called Neuroendocrine Carcinoma or NETs (Neuroendocrine Tumours).
In PRRT, a cell-targeting protein (or peptide) is combined with a small amount of radioactive material, or radionuclide, creating a special type of radiopharmaceutical called a Radiopeptide. When this radiopeptide is injected into the patient’s bloodstream, it travels to and binds itself to the neuroendocrine tumour cells and delivers a high dose of radiation to cancer.
In PRRT, Yttrium 90 (Y-90) and Lutetium 177 (Lu-177) are the most commonly used radionuclides.
WHAT CONDITIONS ARE TREATED WITH PRRT?
PRRT or Peptide Receptor Radionuclide Therapy may be used to treat patients with Neuroendocrine Tumours (NETs) including:
- Islet Cell Carcinoma of the Pancreas
- Small Cell Carcinoma of the Lung
- Pheochromocytoma (a rare tumour that forms in the adrenal glands)
- Gastro-enteropancreatic (stomach, intestines, and pancreas) Neuroendocrine Tumours, and
- Rare Thyroid Cancers that are unresponsive to treatment with radioiodine.
WHEN WOULD THE DOCTOR CONSIDER USING THIS THERAPY?
Doctors might consider this therapy as an option for patients who
- have advanced and/ or progressive Neuroendocrine Tumours.
- are not candidates for surgery.
- have symptoms that do not respond to other medical therapies.
WHAT IS THE MAIN GOAL OF PRRT?
The main goals of PRRT are:
- To provide symptom relief,
- To stop or slow down the tumour progression, and
- To improve overall survival
WHAT ARE THE ADVERSE EFFECTS OF THE THERAPY?
While the administration of PRRT is well tolerated, some patients might experience nausea and vomiting during the amino acid infusion that is managed with anti-nausea medication.
HOW IS PRRT PERFORMED?
Depending on the type of cancer being treated and the medical facility performing the procedure, patients may need to undergo up to 10 PRRT sessions (usually there would be around four-six sessions) spaced two to three months apart.
The procedure may be done as an outpatient procedure or may require a few days of hospital stay depending upon the type of radionuclide being used.
Each PRRT session begins with an Amino Acid Solution delivered intravenously. This is done to protect the patient’s kidneys from the effects of radiation. The radiopeptide is then injected into the patient and that is followed by an additional Amino Acid Solution. The session lasts for approximately four hours.
In some cases, Molecular Imaging Scans may be taken during and following the treatment process to see where the injected radiopeptide has traveled in the body.
WHAT ARE THE ADVANTAGES OF PRRT?
- PRRT and other such molecular therapies offer a more personalised cancer treatment as the radiopharmaceuticals can be tailored to the unique biological characteristics of the patient and the molecular properties of the tumour.
- PRRT is also considered a targeted therapy as the radiopeptides are highly selective in their ability to damage the neuroendocrine tumour cells while limiting radiation exposure to the healthy tissues.
- Also, since PRRT can target the neuroendocrine tumour cells while not affecting the healthy tissues, it has milder adverse effects as compared to chemotherapy.
While PRRT is a treatment option that is extremely effective in controlling Advanced Progressive Neuroendocrine Tumours, it is not a curative procedure. However, it has shown to help relieve symptoms and slow the progression of the disease.
HOW SAFE IS PRRT?
PRRT, like any other therapy, has some adverse effects and risks. It is advised that patients discuss the risks and benefits of PRRT with the Specialist Doctors at the centre. The doctors at the centre will determine whether the therapy is right for the patient given the patient’s medical history. It is also advised that the patients should inform the team of any prior therapies as it can play a role in determining the correct therapy and dosage.