PROSTATE CANCER AND ATOM TREATEMENT

What is PSMA?

It is a acronym of Prostate Specific Membrane Antigen (PSMA). PSMA is a kind of protein that settles on to the cell surface of various tissues and organs in the body. Although it is found in normal tissues and cells, what makes PSMA so important is that it is very intense in prostate cancer cells. The reason for it being intense in prostate cancer cells is unknown. However, this feature of PSMA have led to very effective use in the diagnosis and treatment of prostate cancer. The remarkable increase in the number of scientific studies show that it will give rise to the use of radionuclide labeled PSMA in the coming years.

How does PSMA affect the diagnosis and the treatment of prostate cancer?

Although PSMA name is used because of its widespread understanding, the drug used in the diagnosis and treatment is not PSMA. In the 1980s, small molecules have been developed that inhibit PSMA (inhibitor) to inhibit the function of PSMA. When these molecules are delivered intravenously, they find and stick to the PSMA protein. So, these drugs are programmed to find and stick to the PSMA. However, these drugs (molecules) did not have any positive effect on the patients and they were fallen into disuse. However, in 2012, these inhibitory molecules were labeled with radioactive material and led to a breakthrough in the diagnosis and treatment of prostate cancer. These molecules, which are programmed to find the PSMA protein on prostate cancer, could now carry radioactive material, meaning that now these radioactive material carrying molecules can be used in the diagnosis and treatment of prostate cancer. These small molecules which inhibit the functions of PSMA, are generally referred to as PSMA.

What is PMSA PET/BT?

PSMA molecules are molecules that are programmed to find and stick to prostate cancer cells in the body. Therefore, these are called intelligent molecules. If this molecule is bound to the Ga-68 radioactive material, then PSMA sticks to the prostate cancer cells by taking Ga-68 radioactive material. With the rays of Ga-68 the most advanced imagining device PET makes the imaging possible. The placement of the prostate cancer cells and where it spread can be determined in this way. Ga-68 has a half-life of 60 minutes and disappears in a very short time. The substance Ga-68 emits radiation, which we call gamma ray, and has no curative properties. It gives low dose of radiation to the patient and it is harmless. It is only used for imaging and diagnosis.

What is Lu-177-PSMA and Ac-225-PSMA?

PSMA molecule is an intelligent molecule that is programmed to find and stick to prostate cancer cells in the body. When market with Lutetium 177 (Lu-177) or Actinum-225 (Ac-225), it takes these radioactive substances and makes them enter into the prostate cancer cells. The Lu-177 and Ac-225 contain very high dose of radiation. When the Lu-177 and Ac-225 enter into the prostate cancer cell, it releases very high dose of radiation into the cancer cell and causes the cell to die. Prostate cancer is affected by this treatment regardless of it is position in the body. Lu-177 and Ac-225-PSMA find and kill prostate cancer cells even if in lymph or bone metastases.

What is the difference between Lu-177 and Ac-225?

Radioactive substances mainly emit 3 types of radiation. These are A) gamma, B) beta and C) alpha rays. Gamma rays have no curative effect. These are only used for imaging and diagnosis. Ga-68 emits gamma rays and is used for PSMA PET/CT imaging. Beta radiation is a high radiation containing particles. Lu-177 emits beta particle. The particle can travel up to 10 mm in air and 1-5 mm in tissue. This way the particle leaves very high dose of radiation into the tissue and allow cell to die. Lu-177-PSMA is used for treatment. The alpha ray is a particle with very high dose of radiation. This particle can travel up to less than 0.1 mm in tissue and 1-2 mm in air. This particle leaves 10-15 times more radiation from Lu-177 into prostate cancer and kills prostate cancer cells much more effectively.

What is the difference between Alpha (Ac-225) and beta (Lu-177) treatments?

The radiation released into the prostate cancer cells kill and destroys the prostate cancer cells. The alpha radiation contained by the Ac-225 is much more than the beta radiation contained by the Lu-177. For this reason, Ac-225 effects prostate cancer cells more effectively. Other normal tissues are no affected by the radiation as the distance traveled in the tissue is much shorter. Since the radiation cannot reach to the organs such as bone marrow that make blood cells the risk of being affected negatively is much less. Studies have shown that Ac-225-PSMA treatment is very effective even in patients who progress after Lu-177-PSMA treatment.

How is Ac-225-PSMA treatment is applied?

Ac-225-PSMA is not a ready to use medicine. It needs to be prepared in a hospital laboratory. In order for Ac-225 to be prepared in the laboratory conditions and technical equipment must be sufficient. The preparation of the Ac-225-PSMA is carried out by well-trained radiopharmaceuticals or chemists. In order to understand whether the drug is prepared properly and to determine the amount of the dosage given to the patient experienced physicists are needed. It is to be understood that a well-trained team work is necessary for the application of the treatment. Prepared drug is given to the patient intravenously. Ac-225-PSMA does not emit harmful radiation out of the body. Therefore, the patient does not need to stay in hospital.

Are there any side effects of Ac-225-PSMA treatment?

In most of the patients receiving Ac-225-PSMA, salivary glands are destroyed, and patients develop dry mouth. This problem can be largely eliminated through artificial oral fluids. Patients can tolerate the treatment very easily. Side effects seen in other drugs such as nausea, vomiting, hair loss does not apply to Ac-225-PSMA treatment. 

Do you have any studies regarding the treatment of Ac-225-PSMA?

Ac-225-PSMA treatment is a team work. A medical professional experience is required to determine and deliver the right treatment options to the patient. Appropriate laboratory conditions are required to prepare the drug. Experienced pharmacists or chemists are required to prepare the drug. Experienced physicists are necessary to determine the appropriate dose of the drug. Each member of our team is highly qualified and knowledgeable and experienced in this field. In addition, our team collaborates with the United States Brookhaven National Laboratory as well as the United Research Center in the EU and shares experiences reciprocatively.