Lutetium-177 PSMA Treatment

What is Lutetium-177 PSMA Therapy ?

Cancer is caused by uncontrollably growing and proliferating cells. When cancer begins in the prostate gland tissue, it is called prostate cancer. The condition in which prostate cancer cells spread to other parts of the body forming multiple focuses is called metastatic prostate cancer.

Theranostic is an emerging field in the medical world. It is an approach in which tumor and metastases detected by imaging with a tumor-specific drug and they can be treated with a same specific drug, which is previously known, how far it will go, and how its power will affect the diseased tissue. In prostate cancer, on the one hand, GA-68 PSMA PET/CT can visualize the tumoral tissues of prostate cancer with high sensitivity and specificity, on the other hand, specific and targeted treatment of these tumoral tissues can be performed with Lu-177 PSMA. This is a very successful and new method for theranostic applications.

Lu-177 PSMA therapy is an innovative and effective treatment that is increasingly used to treat metastatic castration-resistant prostate cancer. Generally, it is used with the recommendation of the referring physician when other approved methods are insufficient, shown to be ineffective or patients cannot tolerate them. This treatment; It helps to reduce tumor size and prevent tumor proliferation, as well as reduce signs and symptoms caused by the tumor.

Lu-177 PSMA therapy has passed phase I and phase II trials and is being tested in phase III randomized clinical trials. Therefore, it is not yet a part of routine clinical therapy. Nevertheless, it has been shown that long-term improvement can be achieved with Lu-177 PSMA treatment in many prostate cancer patients. Currently, there are a limited number of clinics in our country and in the world that offer this treatment service for patients with advanced and metastatic prostate cancer.

Most types of prostate cancer have high levels of tumor-like PSMA sought for treatment. However, it is also known that 5 to 10 percent of all prostate cancer patients do not produce PSMA. Therefore, before starting Lu-177 PSMA therapy, imaging with GA-68 PSMA PET/CT is performed to determine if the treatment is targeting the tumor tissue.

How Does Lutetium-177 PSMA Treat?

PSMA is a type of protein found in healthy prostate cell membranes with multiple cellular functions. Although healthy prostate cells naturally produce very low levels of PSMA, cancerous prostate tumors produce extremely high levels of PSMA (usually 1000 times higher than normal prostate cells). This is also valid for prostate cancer metastases in other parts of the body. The 177Lu atom is a radioactive element emitting radioactive beta particles that can be attached to a carrier molecule called PSMA. When Lu-177 PSMA is administered intravenously, it goes to all tumor tissues where PSMA is present and destroys these cancer cells by emitting radiation. Since Lu-177 PSMA therapy targets cancer tissue, the radiation dose received in other parts of the body is very low. The part of Lu-177 PSMA that is not retained by tumor cells passes into saliva, urine and feces and is excreted from the body.

Lu-177 PSMA therapy is performed after the evaluations of a multidisciplinary team.

Who is Lutetium-177 PSMA Treatment Applied?

In patients with metastatic castration-resistant prostate cancer (mCRPC) and approved (alternative) no treatment methods are left / suitable, it can be applied with the recommendation of the responsible physician.

Before therapy, the patient must have gone through the following procedures :

Detection of increased PSMA expression in tumor tissues in GA-68 PSMA PET/CT imaging, at most 2 months before treatment
Having a complete blood count with serum biochemistry including AST, ALT, creatinine, PSA level in serum at least 2 weeks before treatment
Providing information about the pre-treatment stage of the disease and the treatments applied, previous procedures, pathology results
The appropriateness of Lu-177 PSMA therapy should be evaluated by a multidisciplinary team.

Lutetium-177 PSMA therapy cannot be applied in the following situations :

The ECOG performance scale to be 3 or 4 (unless the goal of Lu-177 PSMA therapy is to reduce the symptoms of your disease)
Severe obstruction and enlargement in the urinary tract
Presence of progressive and uncontrolled diseases; including liver and kidney diseases and infections
Suppression of bone marrow function:

– Total white cell count to be less than <2.5×10⁹/L

– Platelet count to be less than <75×10⁹/L

ECOG Performance Scale

0	Fully active, able to perform all pre-illness activities without restrictions.
1	There is a limitation in vigorous physical activity, but he can stand and do soft work. For example; mild home and office work
2	Standing and doing his own work, but unable to work and able to spend more than half of the daylight hours on his feet.
3	Difficulty self-care, sleeping for more than half of the daylight hours or sitting in a chair.
4	Cannot self-care, fully dependent on chair or bed.

Is Lutetium-177 PSMA Therapy Safe ?

The radiation used in Lu-177 PSMA treatment is designed only to destroy cancer cells. Treatment with theranostics is more individual, so that cancer and metastases are effectively detected first. Then, the whole body dose is kept to a minimum and the cancer cells are destroyed by irradiation. Blood tests to ensure that the radiation does not damage healthy tissues; Imaging is also performed to ensure that the radioactive material in the tumor sites is properly placed.

Your Specialist Nuclear Medicine Physician will guide you about the possible side effects of the treatment and provide necessary advice. As the treatment is directed towards the tumor, serious side effects do usually not seen in most of the patients treated with Lu-177 PSMA. However, in some patients; Nausea, dry mouth, fatigue, decreased kidney function, and especially in patients with bone lesions, temporary decrease in blood cell production can be seen. The most common side effect is mild nausea. To prevent this, your physician will recommend anti-nausea medication if needed.

Preperation Before Lutetium-177 PSMA Therapy

Information Required During the First Visit

It is important that you bring the information and documents listed below with you on your first application to the clinic. The digital preparation of your patient information (DICOM, JPEG, PNG, PDF, Microsoft Word (.doc, .docx) etc.) will allow it to be shared quickly and easily by e-mail and will greatly facilitate the evaluation of your disease.

Contact information (home / work / mobile phone number, e-mail address) of you and your referrring physician
Your up-to-date physician reports
Your pathology reports
Blood tests
Reports of your previous images and original films / CDs / DVDs such as whole body bone scintigraphy, CT, MR and Ga-68 PSMA PET/CT

In addition, your Nuclear Medicine doctor will order the following blood tests. Since these tests are expected to show your condition during treatment, they should be done at least 2 weeks before treatment.

PSA
Complete blood count
Sodium
Potassium
Phosphate
Urea
Creatinine
Alkaline phosphatase
Albumin
AST
ALT
LDH
Bilirubin
Total protein
Creatinine clearance in 24-hour urine

Your physician may also order additional blood tests as needed.

Preperation Before Lutetium-177 PSMA Therapy

You need to make sure that at least 4 weeks have passed since your last chemotherapy administration. Before treatment, it is important that you have used the medication prescribed by your Nuclear Medicine Physician as recommended.

Since you will wear your own clothes during the treatment, we recommend that you bring comfortable and wide clothes with you. You can use the old clothes that you can throw away after wearing it during the treatment. Since the vascular access placed on your arm or the back of your hand will be used both for your treatment and to taking of blood for the tests, it will be useful to choose short-sleeved or wide-sleeved clothes.

How is Lutetium-177 PSMA Treatment Applied?

Before treatment, if you do not have any special restrictions, you will be asked to drink plenty of water. Lu-177 PSMA will be administered through a vein placed on your arm or back of the hand in less than 1 minute, then saline will be given slowly through the vein for about half an hour. During and after the injection, you must remain in the clinic for the period specified by your Nuclear Medicine Physician. Urinary catheters are used with the recommendation of the Nuclear Medicine Physician in our patients who have urinary retention problems.

Your total treatment consists of 2 to 6 cycles to be applied at 6-8 week intervals. You should avoid close and prolonged contact with people until 24 hours after the injection (it is recommended that you do not participate in flight / travel / public events).

If needed, anti-nausea medication can be given during or after your treatment.

Lu-177 PSMA to be used for treatment is produced in the radiopharmacy department of the institution to be treated and applied in treatment rooms specially prepared for radionuclide treatments. Unless otherwise stated due to radiation in your body, you will need to stay in the hospital in this special lead-covered room, in the form of a daily or overnight stay, where a specialist team will coordinate the treatment. During the first 12 hours after treatment, a large amount of radioactivity will be excreted through your urine.

Your physician will perform a whole body scan in the Nuclear Medicine Department between 1 and 48 hours after the medication is given.

As a precaution, no visitors are allowed during your stay in the hospital. However, if you want, you can make a phone call.

Blood tests will be done approximately 2 weeks to 6 weeks after treatment.

How Many Cure Treatments Are Applied?

Usually, 2 to 6 cures of treatment are given every 6-8 weeks. Your Nuclear Medicine physician will see you after each cycle in order to re-evaluate your health and response to treatment. Subsequent treatments is planned according to PSA level and based on its effect on your blood cells, kidney, and liver. This clinical evaluation will be done 2 weeks before the next course of therapy. In this evaluation, blood tests, bone scintigraphy, Ga-68 PSMA and 18F-FDG PET/CT are performed.

What Should You Do After Lutetium-177 PSMA Treatment?

You are usually discharged 24 hours after treatment. In such treatments, the radiation stays inside the body and emits very little outside the body. As we mentioned before, as a precaution, no visitors are allowed during the treatment. After your discharge, your family and friends are no longer at risk. However, we recommend that you take some reasonable precautions, as listed below:

For a week after treatment, flush the toilet twice after each toilet use.
Avoid all contact with young children and pregnant women for 3 days..
Restrict close contact with other adults for 3 days.
Avoid sharing a bed with another person for 3 days.
On the day of treatment and afterwards, follow the advice your physician will give you according to your personal conditions.