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.

An In-Depth look at Prostate Cancer

Cancer is an abnormal cellular growth in a specific body region that is able to spread internally and cover other areas. If left untreated, it causes a number of life-threatening conditions that may even lead to fatality.

World Health Organization (WHO) notes cancer to be the second leading cause of death. An estimated 9.6 million deaths have occurred due to it in 2018 alone. That amounts to 1 in every 6 losses of lives.

What is Prostate Cancer?

Prostate cancer refers to the development of cancer in the prostate gland of the male reproductive organ.

Its growth rate is observed to be highly inconsistent, with a majority of it being slow to form while some manifesting at a fairly rapid pace. But the fact that it may spread out towards other body areas, specifically bones and lymph nodes, is proven to be conclusive.

Symptoms of Prostate Cancer: Early Warning Signs

Prostate cancer may prove to be hard to detect due to it having zero or faint traces of initial symptom occurrence. However, if left untreated, a number of symptomatic constraints pertain to it can be seen. This includes –

Frequent fatigue
Pain in the back or hip
Blood in urine
Unexplained weight loss

Adverse effects and complications

Presence of prostate cancer in the body can result in a number of adverse effects and complications. Here are a few of the most common ones -

Spreading to other areas (metastasize) - Like every other cancer condition, prostate cancer has an in-born tendency to spread to other body areas such as the bladder or pancreas or even bones. The condition is still treatable but treatment is much harder.
Urination disorder (haematuria) - With the on-set of prostate cancer, the urinary tract of the patient may get damaged. This causes extreme difficulty in urinating or even the formation of blood during its dispensing. Treatment of prostate cancer may result in mitigation of this issue.
Inability to gain erection (erectile dysfunction) – Erectile dysfunction is a one of the most commonly occurring symptoms of prostate cancer. Through radiation therapy and surgery, this effect might be alleviated but treatment of prostate cancer, is noted to provide a long-lasting solution.

What increases the risk of prostate cancer development in the body?

Prostate cancer is known to be one of the most commonly occurring condition. It’s formation is attributed towards certain aspects. The 3 of them ae mainly associated with it are -

Age – 99% of prostate cancer cases appear in males aged 50 and above. This is primarily attributed to the fact that with advancement of age, body metabolism is known to depreciate. As a result, cancer-born defects and abnormalities are able to face minimal resistance from the body immune system.
Ethnicity – Medical studies have concluded that people of African descend are 1.6 times more likely to develop prostate cancer. This is primarily due to the difference MSMB gene secreted by certain cells in the prostate.

Dietary habits – A lower concentration of vitamin D is shown to present a higher chance for prostate cancer development. This is why, dieting on egg, fish, cheese, etc. can reduce chances of prostate cancer occurrence.

Prostate Cancer Screening and Diagnosis

In order to detect the presence of prostate cancer in the body, multiple tests are initiated on the patient. Here is a brief overview of the procedures followed –

1. Preliminary Screening

No symptomatic presence suggests prostate cancer development. However, specific changes in the inner body anatomy can be observed. Here are some of the tests performed -

Digital Rectal Examination (DRE) – The doctor examines lower body for issues. Anomalies in the prostate gland are subsequently detected in the process.
Prostate-specific antigen (PSA) test - The blood concentration levels in the body are substantially increased during prostate cancer occurrences. This proves its formation.

2. Diagnosis

If evidence of prostate cancer is found prior to the preliminary examination, the patient is recommended to undergo a diagnosis examination. Here are some of the diagnostic tests performed -

Ultrasound examination – A small cigar-shaped probe is inserted into the rectal cavity. The probe emits sound waves that create a clear picture of the prostate gland.
CT scan – A CT scanner allows a particular body region to be cross-examined. In this case, the scan is performed on the prostate region. Any anomalies relating to cancer growth formation can be subsequently detected.
Digital Rectal Examination (DRE) – This diagnosis procedure involves the insertion of finger into the rectal cavity by the diagnostic doctor. If the surgeon comes across any anomalies in the region that might point towards prostate cancer.

Biomarker test – A person with cancer will develop a substance known as biomarker within the blood or urine. It is produced by the body itself in response to cancer tumour growth and spread. The diagnosis doctor is set to run a diagnostic check-up on the obtained sample to verify it.
PSA test – PSA or Prostate-specific Antigen is a substance developed by certain body cells. Studies have found that it belongs to the protease family of kallikren, which is why it is dubbed human kallikrein 3 (HK3) By measuring its production rate from the Prostate gland, examiners can determine if prostate cancer is present in the body.

Prostate Cancer Treatment

Several promising treatment procedures to contain prostate cancer spread and growth are known to exist. A few of these include –

1. Radical Prostatectomy

This involves the surgical removal of the prostate gland and associated tissues nearby. Before it commences, a catheter tube is inserted into the bladder to drain out the urine.

This treatment is known to be only effective if the prostate cancer condition has not spread to other body regions.

2. Nuclear Medicine Therapy

Nuclear Medicine Therapy, also known as targeted radionuclide therapy (TAT), it involves the infusion of medical drug contain radioactive molecules. It travels to the cancer-afflicted region and delivers the therapy molecules which destroy the cancer cells.

3. Cryosurgery

This surgery technique refers to the Creation of a frigid temperature condition. This destroys abnormal tissue or cellular growth. For this surgery technique, the prostate gland is surgically removed first before enveloping it in cold temperature to destroy the cancer tumour cells. The surgery technique is still in experimental stages at this point in time.

4. High intensity Focus Ultrasound Therapy

In this therapy a high energy infused beam of ultrasonic sound, is projected onto the prostate cancer affected area. In doing so, cancer tumour cells are eradicated one by one. This therapy is still in its infantile stage, but the implications are noted to be promising.

5. Proton Beam Radiation Therapy

A single beam of proton consists of a number of high energy light particles. By focusing a beam of protons onto the cancer affected region in the prostate area, tumour cells can be removed. This therapy is considered to be the most consistent and reliable therapy in prostate cancer treatment.

6. Photodynamic Therapy

Photodynamic therapy or PDT uses special drugs that are noted to be photosensitizing agents or substances that can only react by applying a beam of light. These chemicals enter the prostate region of the patient prior to intravenous injection. Once it reaches its destination, it is autoactivated on the application of a certain ray of light to release chemicals. These chemicals destroy the prostate cancer tumour cells.

Stages of Prostate Cancer

To measure the degree of severity of the cancer spread, doctors assign a certain value to denote it. The stages and its implications are as follows-

Stage 1

At this stage, it is relatively harmless. The parent prostate cancer tumour is not noticeable due to the fact the size of the tumour is minimal. As a matter of fact, they tend to resemble healthy cells.

Stage 2

The parent cancer tumour is slightly larger now but is quite small. However, it is known to be in the process spreading at a rapid pace.

Stage 3

The parent cancer tumour is significantly larger and would likely spread to other body areas

Stage 4

Prostate cancer has spread out to other body areas.

With proper diagnosis, the doctor is able to find out the cancer stage and proceed with the treatment accordingly.

Ref:

https://www.who.int/news-room/fact-sheets/detail/cancer

https://en.wikipedia.org/wiki/Prostate_cancer

https://www.cancer.net/cancer-types/prostate-cancer/risk-factors-and-prevention

https://www.mayoclinic.org/diseases-conditions/prostate-cancer/diagnosis-treatment/drc-20353093

https://www.snmmi.org/AboutSNMMI/Content.aspx?ItemNumber=12772