Prostate cancer is the most widespread type of oncological pathology among men. Doctors from all over the world pay attention to timely prophylaxis and diagnostics, because at the early stages this disease is treated much easier. At the late stages, especially when there are metastases in other organs and skeleton, there are only few therapeutic options. Targeted alpha irradiation with the help of radioisotope Actinium-225 is an innovative technique that precisely destroys tumor cells and metastases even when the other methods of treatment are ineffective. Results of the clinical trials that have been completed in 2018 give many patients a chance to defeat this disease.
How does the targeted radionuclide therapy work?
During the search of new therapy methods for patients with advanced stages of the prostate cancer, the scientists from the German Cancer Research Center (Deutsche Krebsforschungszentrum, DKFZ) created a unique molecule, called PSMA-617. PSMA is a "prostate specific membrane antigen". It is a kind of protein that is located on the surface of the prostate cells. It is important to notice that its content in cancer cells is hundreds of times higher than in the healthy ones.
Molecule PSMA-617 purposefully finds prostate cancer cells, including primary tumor and distant metastases, and binds to them. Scientists used this ability to develop a new technique called targeted alpha therapy.
According to the intention of the nuclear medicine doctors, the molecule PSMA-617 acts as a carrier for radionuclides. Upon decay, these substances release radioactive radiation. After the administration of these drugs, PSMA-617 binds to prostate cancer cells, and the tumor undergoes targeted irradiation. Oncological cells die, and surrounding healthy tissues remain viable. Due to this method, targeted alpha therapy is better tolerated than a conventional irradiation.
Of course, not all radioactive substances are used in nuclear medicine. Only therapeutic radionuclides correspond to the requirements of the human radiation safety. For example, Lutetium-177 and the innovative Actinium-225 have been used in this field for a long time.
Why do the doctors need Actinium-225, if they already have Lutetium-177?
PSMA-therapy with Lutetium-177 has become firmly established in the practical medicine of developed countries. Lutetium-177 is an active source of beta radiation. This isotope helps in the diagnostics and treatment of metastatic prostate cancer.
Despite the high effectiveness of the method, not all patients responded to Lutetium-177 therapy, so the trials continued. Clinical trials of the Actinium-225 isotope lasted for more than 2 years. The final result has fully justified such a time-consuming process. Two patients with the extensive metastases of the prostate cancer who were in critical condition at the time of enrollment responded to therapy and achieved stable remission after 3-4 sessions.
Actinium-225, as opposed to Lutetium-177, is a unique source of alpha radiation. Each atom of Actinium-225 emits four high-energy alpha particles during the decay. Alpha radiation causes double breaks of the DNA helix in tumor cells. Cells with destroyed DNA are unable to live or reproduce. At the same time, a similar influence on the neighboring healthy cells is absent due to the short range of alpha radiation, namely 0.04 mm.
PSMA-therapy with Actinium-225 is effective even in cases when all other therapeutic possibilities have already been tried. It helps patients with metastatic cancer, resistant to chemotherapy and hormonal drugs. Even in case of PSMA-therapy with Lutetium-177 ineffectiveness, substitution of the radionuclide with Actinium-225 significantly improves the results of therapy and future forecasts.
How the treatment will be carried out?
The patient stays in the department of nuclear medicine when PSMA-therapy with Actinium-225 is performed. This is a specialized department equipped according to the strict requirements of radiation protection. Only clinics of the highest level have such departments. Both, a therapy session and monitoring in the hospital, take only 3-4 days. After that, the person returns to his normal life. Such period is sufficient to ensure that the power of radioactive radiation is reduced to the permissible level and the patient may return to the society.
Before starting the therapy, an obligatory examination is carried out. It includes the following aspects:
- PSMA-PET-CTion of metastases in the spine
When the results of the examination are received, the preparation for the procedure begins. It implies the following:
- Insertion of venous catheters for the convenience and safe injection of radiopharmaceutical.
- Cooling of the salivary glands in order to slow the blood flow and, accordingly, reduce the accumulation of the radiopharmaceutical. Usually, the tissue of salivary glands actively accumulates radionuclide and can be damaged.
- Intravenous injection of saline provides additional protection of the kidneys.
Intravenous injection of radiopharmaceutical through the catheter takes only 10-15 seconds. Actinium-225 spreads throughout the body with the blood flow and binds to the prostate cancer cells. Radionuclide distribution is controlled with the help of scintigraphy. This examination method is more accessible than PET-CT and allows to additionally assess the presence and the size of metastasis in the bones.
In order to achieve the most favorable result, PSMA-therapy with Actinium-225 is performed in several sessions. This increases the exposure time of the radionuclide to cancer cells and, accordingly, increases the effectiveness of the procedure. The number of procedures is determined by the physician individually based on the clinical situation and the results of the follow-up examinations.
The results of PSMA-therapy with Actinium-225
The first clinical, biochemical and radiological results of PSMA-therapy with Actinium-225 reveal themselves within a few weeks after completion of the procedure. The most notable aspects among them are:
- PSA level. PSA is the main oncologic marker associated with prostate cancer. After the treatment, its level reduces by 50% or more in all patients. In some patients, it even falls below the laboratory detection level – 0.1 ng/ml.
- Control PSMA-PET-CT. The results of tomography demonstrate a decrease in the number and size of metastases, as well as regression of the primary tumor.
It should be noted that the procedure is well tolerated. When PSMA-therapy with Actinium-225 is carried out, there are no side effects which are typical for conventional radiation therapy or intensive chemotherapy at the stage of metastasis. Short-term nausea is easily eliminated with the help of symptomatic medicines. The only significant side effect is dry mouth.
Another advantage of this technique is the low risk of relapse. The largest clinical trials of PSMA-therapy with Actinium-225 lasted 3 years. During this time, the remission periods up to 2 years were recorded in patients with the advanced stages of prostate cancer. In general, the life expectancy and its quality significantly increased after the treatment.
Where you can undergo PSMA-therapy with Actinium-225
PSMA-therapy with Actinium-225 is performed in Germany, at the home country of this type of treatment. The specialists of several German clinics in cooperation with the research centers have developed this technique, evaluated its effectiveness during the clinical trials, and introduced it into the practical medicine.
Undoubtedly, other countries also seek opportunity to provide medical care at the same level. For example, in Russia the similar project with the usage of another radionuclide is being developed. According to the plan of scientists, substituting Actinium-225 with other substance may probably make the technique cheaper and easier in terms of technology. Nevertheless, it is impossible to predict the effectiveness of such an approach.
Fortunately, German clinics are open for the international society and take foreign patients for treatment. The procedure of registration for the PSMA-therapy with Actinium-225 in this case has its own peculiarities. For competent and effective communication with the administration of clinics, it is better to use the help of a certified medical tourism operator, the company Booking Health.
Booking Health annually helps thousands of patients with prostate cancer to undergo treatment and defeat the disease. We accompany the patient from the moment of choosing the clinic till returning to his native country. Our company considers all the medical and organizational details, such as:
- Issuing of an invitation for getting a visa for treatment as quickly as possible
- Fixing an appointment at the suitable time
- Organization of a preliminary examination, including PSMA-PET-CT
- Transfer from the airport to the clinic and back to the airport
- Services of the interpreter and your personal medical coordinator
- Health insurance against complications covering up to 200.000 Euro
- Preparation and translation of medical reports and recommendations from the clinic
- Assistance in subsequent communication with the physician, including remote consultations with the help of unique medical document management system E-doc and the organization of further treatment
Booking Health makes the latest medical achievements available. Patients from all over the world can undergo PSMA-therapy with Actinium-225 right now, without waiting for adjusting of this technique to possibilities of their countries.
Choose treatment abroad and you will for sure get the best results!
The Booking Health portal presents 46 German clinics specializing in PSMA therapy with Actinium-225
Author: Dr. Nadezhda Ivanisova