Dr. Kemal Unal, ACIBADEM expert in nuclear medicine
According to figures provided by the World Health Organization, prostate adenocarcinoma is the second most common cancer in men and ranks 4th in the top of the cancer types, after the lung, breast and colon. Usually, urinary problems and erectile dysfunction are symptoms that bring patients to the doctor. Prostate cancer occurs predominantly after age 65. Fortunately, the disease of the prostate gland can be initially diagnosed and successfully treated by chemotherapy, radiotherapy and surgery. The advances in medicine in the case of prostate cancer also regards the treatment of advanced cases. Prostate cancer is treated in a team, as is the protocol applied in ACIBADEM clinics in Turkiye. The medical team includes the urologist, oncologist, imaging specialist, surgeon, pathologist and radiation oncologist. In recent years, a major contribution to the staging of the disease and the treatment of advanced cases has been brought by nuclear medicine.
“In our department, we use the imaging protocol with Ga 68-PSMA in patients diagnosed with prostate adenocarcinoma, to determine the stage of the disease. We can also use Ga 68-PSMA in patients with prostate adenocarcinoma who have metastases, to evaluate the treatment response. Furthermore, if the patient has a new lesion, we use Ga 68-PSMA to reevaluate the disease stage. Ga 68-PSMA acts as follows: when we inject the patient with this radiotracer, it attaches to a receptor in the prostate adenocarcinoma membrane, then enters the cytoplasm. Thus, we manage to visualize prostate carcinoma cells. What we do is called molecular imaging with Ga 68-PSMA”, says Dr. Kemal Unal, an expert in nuclear medicine.
The use of protocols with Ga 68-PSMA is applied after a careful selection of patients, depending on certain parameters. These may be PSA levels in the blood or a cancer suspicion after an imaging investigation. The use of Ga 68-PSMA radiopharmaceutical does not require prior preparation and has no adverse effects.
“No special preparations are made before the test; the patient can continue the medication. We inject the radiotracer Ga 68-PSMA within the nuclear medicine department, and the patient stays quiet for one hour. Then follows the investigation that is done with the help of PET-CT: the scan of the whole body takes 20-30 minutes. Then, if there are no artifacts (situations that occur if the patient has metal implants or as a result of breathing), we send the patient home. The only thing the patient has to do is avoid contact with pregnant women and children for a day, because there is a radioactive emission. There are no side effects of imaging protocols using Ga 68-PSMA”, adds the nuclear medicine expert from ACIBADEM.
Another effective solution in nuclear medicine is the treatment with Lutetium 177-PSMA. This radiopharmaceutical is used especially in cases of metastases.
“If patients have metastases and are advised with hormone and chemotherapy, they may become resistant to these therapies (castration-resistant prostate adenocarcinoma) and then the only solution could be Lutetium-177 therapy. At present, it is known that if the tumor cells have a good uptake of Ga 68-PSMA, then they will also have for the Lutetium-177 therapy. The protocol is called theranostics, it is a new term in nuclear medicine. Lutetium -177 therapies are personalized and thus, we manage to treat all lesions at the same time. For example, if the patient has 100 metastases, no external radiation therapy may be applied to each lesion. But when we inject Lutetium-177 into the body, the tumors absorb lutetium and thus, we can irradiate several lesions in one cycle”, explains the benefits of Lutetium-177 therapy Dr. Kemal Unal.
For Lutetium-177 therapies, patients are carefully selected based on blood test values and the status of liver and kidney functions. This is because radiation therapy can worsen the condition of patients with kidney or liver problems. Patients will undergo analyzes during treatment to assess their health status. Adverse effects may occur in between 3 and 5 percent of the patients.
“We expect a 10 percent of patients to completely response to treatment. Most patients have a partial response to treatment, but this is a good thing because these patients have no other therapeutic options. Some have a stable response, which means that the disease stagnates, which is good for them. 20 or 30 percent of patients are experiencing a progression of the disease under the treatment with Lutetium-177, but for them we also have solutions such as actinium therapy that are already being done in Europe and Turkiye. Actinium is much more energetically active than Lutetium-177, it contains alpha particles, not beta like lutetium. It is an alternative for patients who do not respond to Lutetium-177. Anyway, most patients respond to lutetium or have a stable situation. Also, in half of the patients taking Lutetium-177, the level of PSA in the blood is reduced”, describes the nuclear medicine expert the effects of radiopharmaceuticals.
Treatment with Lutetium 177 can be done at any age and does not affect long-term fertility. At present, nuclear medicine offers diagnostic and treatment solutions for neuroendocrine tumors. These are rare cancers that develop from neuroendocrine cells in the body and are predominantly located in the lungs, appendix, small intestine, rectum and pancreas. Hormonal tests, imaging investigations and biopsies are included in the diagnostic protocol for endocrine tumors, along with the protocols with Ga 68- DOTATATE.
“GA 68- DOTATATE is the latest generation method that offers the best results in diagnosing neuroendocrine tumors. This method offers the best accuracy compared to other imaging methods; we are talking about molecular imaging. We use Ga 68- DOTATATE for staging, restaging and evaluation of treatment effect. Sometimes, we use the protocol to identify the initial outbreak of disease when patients have high blood levels of tumor markers for neuroendocrine tumors. There are cases when no obvious lesions appear during classic imaging investigations such as tomography or other radiological investigations. So, we turn to Ga 68-DOTATATE to investigate patients, to find the source of the disease and to stage the disease. For Ga 68-DOTATATE no special preparation is made for patients, but they should discontinue treatments with somatostatin analogues because they may interfere with the uptake of radiopharmaceuticals and influence the outcome. Thus, if patients have long acting therapy with somatostatin analogues, they should stop them before 4 weeks of the investigation with Ga 68- DOTATATE. In patients who do not have active therapies for a long time, the investigation can be done after a day’s pause”, details the investigation protocol with Ga 68-DOTATATE Dr. Kemal Unal.
And in the case of neuroendocrine tumors, doctors apply Lutetium-177 protocols, when other solutions do not work.“In the center where I work within ACIBADEM, we apply these therapies for two years. It is a relatively new technology; in many countries it is not available yet. But in advanced countries, it is routine, and we are very glad that we can apply it in ACIBADEM because it is the gold standard for these conditions. In these conditions, Lutetium-177 is not the first-line treatment, but when there are no other solutions for neuroendocrine tumors, it is good that we have this solution that we offer to patients, a solution that is increasingly available in the medical literature. Also, with these modern methods, we can provide solutions for patients with metastases, with few adverse effects. In the case of Lutetium 177- DOTATATE therapy, in most patients we expect a stable or partial response. In very few patients, there is resistance to radiopharmaceuticals. But most patients carefully selected by us can benefit from these therapies”, concludes Dr. Kemal Unal.
