Which Patients can benefit from PRRT

PRRT is a short form for Peptide Receptor Radionuclide Therapy. It is also known as molecular therapy or radioisotope therapy. PRRT has been found to be very effective in the treatment on certain cancers called Neuro endocrine tumours or NETs as some of you may know them.

PRRT is an integral part of Nuclear Medicine Therapy and when a PRRT is conducted, the following steps are carefully undertaken and reviewed by trained Nuclear Medicine Physicians.

1. A cell targeting protein or peptide is combined with a Radioactive Material, creating a Radio Peptide. This cell targeting peptide is similar to Somatostatin a naturally occurring hormone in the human body.
2. This radio peptide created with a combination of a Peptide and Radioactive Material is then injected in the patient’s blood stream.
3. This radio peptide has a property to bind with the neuroendocrine tumour cells in the body of a patient. This is achieved because of a cell surface protein (Somatostatin Receptors) present in the tumour cells which have the property to bind to Somatostatin
4. This radio peptide has the capability to deliver high dosage of radiation directly to the cancer cells - this leads to structural changes in the tumour cells and ultimately killing them.
5. There are two types of Somatostatin Receptors – which are made in the labs at our Nuclear Medicine Centre in Gurgaon India – These are DOTATOC and DOTATATE.

This completes the fundamental steps of the PRRT process, now let’s also understand the radioactive chemicals (also called radionuclides) involved – this would help us understand the process a little deeper. So, which are these radionuclides?

Yttrium 90 (Y90) and Lutetium 177 (Lu177) are the most commonly used radionuclides.

What conditions can be treated by PRRT?

PRRT, like we mentioned earlier, is a procedure that is used for treating Neuroendocrine Tumours (NETs) – gastro-entero-pancreatic NETs, which arise from the stomach, gastrointestinal tract, pancreas, islet cell carcinomas of the pancreas (These NETs are included in the US Federal Drug Administration {FDA} approved indication)

PRRT is a recommended option for patients typically with the following conditions:

1. Patients with Advanced Metastatic or progressive NETs which are positive on Somatostatin Receptor Imaging (Ga68-DOTATATE PET CT or other equivalent scans your Doctor may recommend)
2. Patients without options for Surgery
3. Patients who are not responding to other therapies

The objective of PRRT therapy is symptom relief, slow down or stoppage of tumour progression and to improve survival and quality of life.

Now that we know about which patients can benefit from PRRT, let’s go a bit further to understand: 

1. How is PRRT performed?
2. What are the advantages of PRRT?
3. Is PRRT safe?
4. What are the post-therapy guidelines?

How is PRRT Performed?

The most common procedure followed during the PRRT process (as per US FDA and European Medicine Agency Approval) includes a series of 4 cycles of PRRT Treatments with Lu177 DOTATATE approximately 8 weeks apart. The treatment at our Nuclear Medicine Department at Fortis Memorial Research Institute, Gurgaon India can be done on an outpatient basis or may require hospitalisation of a few days. The Nuclear Medicine Physicians at our centre led by Dr. Ishita B Sen and Dr. Vineet Pant decide if a particular patient requires hospitalization or can be discharged the same day from the hospital.

The procedure begins with a discussion with the Patient and the caregiver and proceeds with the patient's scan or review of the medical history and medical reports. The patient is then given appropriate anti-nausea pre-medicines followed by Amino acid solution. The amino acid solution is given intravenously to protect the Patient’s Kidneys from the effects of the treatment. The treatment in total last about 7-8 hours. The patient is then injected with the treatment followed by Amino Acid Solutions again. 

Post the treatment, a Dosimetry Molecular Imaging Scan is done to note where the injected radio-peptide has travelled in the patient’s body.

What are the advantages of PRRT?

PRRT Treatment offers personalized cancer treatment, the radio peptides used (Lu 177 or Y 90) can be tuned to the tumour characteristics and the molecular property of the tumour cells.

PRRT is a selective therapy because the radio peptide cells bind themselves with the tumour cells directly and deliver a high dosage of radiation to kill tumour cells (Targeted Therapy). This also prevents damage to healthy cells in the body by limiting their exposure to radiation. PPRT has been found to be effective in inoperable or metastatic and progressive Neuroendocrine Tumours (NETs)

PRRT is well tolerated and is known to help relieve symptoms, arrest tumour growth, shrink tumour lesions, trials with PRRT have noted improved progression-free survival for the patients.

Is PRRT safe?

PRRT is generally well tolerated but like all other therapies it has its side effects and risks. Nuclear Physicians at our centre will take you through the details of the risks and side effects before the patient opts for this therapy

Side Effects of PRRT may include Nausea, vomiting, long term side effects include suppression of blood counts, permanent renal toxicity, Myelo Dysplastic Syndrome (MDS)

What are the post-therapy guidelines?

• Maintain good bathroom hygiene. 
• Follow radiation safety protocols provided by highly skilled Nuclear Medicine Physicians at our centre. 

If you find this article informative please leave a word in the comment section below.

Original Sources: https://nuclearmedicinetherapy.in/blog/which-patients-can-benefit-with-prrt

https://nuclearmedicinetherapy.in/blog/is-prrt-safe-for-you

Also Read: How PRRT Therapy works in Cancer Treatment

How PRRT Therapy works in Cancer Treatment

PRRT Therapy (Peptide Receptor Radionuclide Therapy) presents a reliable and consistent solution for cancer treatment. It is both versatile in dealing with several different types of cancer and provides a long-lasting measure to keep the spread and growth of the tumor cells. Let get into the specifications of it by taking a more in-depth look.

What is PRRT?

Peptide Receptor Radionuclide Therapy (PRRT) is a targeted therapy. Medication drugs and are provided to the patient, that identify and attack the cancer cells and cancer afflicted cells. Subsequently, the high amounts of radiation provided help reduce the growth and spread of the cells.

Being a targeted therapy, PRRT is noted to cause only minor side-effects post-treatment. The majority of the radiation is concentrated only on the affected cells and not anywhere else in the body.

How is PRRT administered?

Before the start of the procedure, certain medications are administered to the patient.

1. Amino acid solution – To prevent the development of toxicity in the kidneys (or nephrotoxicity), an amino acid solution is infused into the patient. Analgesia – These help in improving the patient's psychological state before the treatment by suppressing emotions of apprehension, anxiety, etc. In the process, this lowers the requirement for anesthetic medication.

2. Antimuscarinics – With the help of these, dry mouth during the treatment process or xerostomia is prevented.

Prior to administering these medications, as per the patient's condition, the treatment proceeds –

1.   Peptide protein is bonded with a radionuclide molecule

2.   The combination is introduced into the patient's bloodstream through intravenous injection.

3.   The radiopeptide travels through the bloodstream and enters the cancer-affected region.

4.   It forms a molecular bond with the protein receptors (somatostatin) in the cancer cells.

5.   Due to a high dose of radiation content, it destroys the bonded cancer cell.

Due to the targeted nature of this therapy, the other regions in the patient's body are not harmed. This mitigates the chances of unnecessary cellular damage.

What are the benefits of PRRT as compared with other cancer treatment therapies?

PRRT presents a host of advantages and benefits for cancer treatment. Which is why it is majorly the preferred choice of therapy. Here are some of the primary benefits of PRRT –

·  PRRT can be personalized to suit the patient's condition and medical characteristics.

· As a targeted therapy, PRRT only affects the specified body region, causing minimal radioactive exposure to healthy tissues

·  The treatment can readily progress to tumor cells in various body regions, making it suitable for metastasized cancer conditions

All these present PRRT as a promising treatment solution for cancer growth.

Does PRRT produce any side-effects?

PRRT is usually well tolerated by most. However, in certain aberrant cases, it is os associated with a series of side-effects that produce minimal discomfort and/or hindrance to bodily activities and functions. These include –

·  Nausea

·  Vomiting

·  Abdominal pain

·  Hair loss

The side-effects type, as well as its duration, varies from patient to patient, which usually lasts from a few hours to several days.

Terminologies associated with PRRT

Alpha PRRT

Alpha PRRT is a variant of the PRRT that utilizes alpha particle radionuclide from isotopes of Actinium (Ac), Bismuth (Bi) and Lead (Pb).

Lutathera

Lutethera or lutetium 177 DOTATATE is a medication used in PRRT. It is approved for usage by several major government bodies including the USA-based FDA (Food and Drug Administration). It is used in PRRT to create radio-peptide molecules.

Somatostatin

Normally, these refer to hormonal traces found in the body. Combining with alpha-emitted radioactive particles, they combine with the alpha radio-molecule to produce radio-peptide, which can bind with the tumor cells and destroy them.

Bone Metastases

Tumors spread to the bone are commonly referred to as bone metastases. They generally are the result of cancer tumour originating in an another body area and being spread to the bone-mass.

Variants of PRRT

Medical professionals and scientists have devised different approaches to PRRT which subsequently produced a varying list of results. Here are the different approaches used –

Bad Berka Approach

This is a specific technique used in PRRT developed by Dr. Baum and his team at the German town of Bad Berka. As per this approach, radioactivity would be dispensed on a lower amount at shorter bursts. This allowed PRRT to deliver treatment

Zentralklinik Approach

This resulted in the performance of PRRT under a single team comprising of medical professions specializing in an interdisciplinary approach. It consisted of the following medical specialists –

·  Surgeon

·  Endocrinologist

·  Radiologist

·  Anesthesiologist

·  Palliative medicine specialist

Together, they were able to provide rapid treatment for patients.

Availing PRRT

PRRT is readily available throughout the world. India happens to be one of the countries that provide one of the best facilities and specialists for diagnosis and treatment. This is why, if you happen to be on the lookout for PRRT, be sure to consider having the procedure done from there.

For further information and/ or consultation, Visit NuclearMedicine Therapy, do call or write to us: +91 98111 27080, info@nuclearmedicinetherapy.in

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