Smart Radiation Therapies: Radionuclide Treatments

As cancer, one of the most significant diseases of our time, becomes increasingly widespread, new and more effective treatments are emerging. One of the most important treatments is "Radionuclide Treatments"... In the Nuclear Medicine Department, patients diagnosed with prostate cancer and neuroendocrine tumors can be treated with the most advanced methods using radioactively labeled substances with targeted radiation. Radiation, labeled with a substance that targets the tumor tissue, is administered to the patient through the bloodstream and travels to all tumor cells in the body, destroying them. This treatment works similarly to radiotherapy, but provides the opportunity to destroy the tumor from the inside with internal radiation. As a targeted treatment, this method does not harm healthy cells in the body; not only does it preserve the patient's quality of life, but it also prolongs their lifespan. Focusing solely on destroying tumors without affecting other healthy tissues and organs, this treatment can also be referred to as "Smart Radiation Therapies."

 

Anadolu Health Center Nuclear Medicine Specialist Assoc. Prof. Dr. Kezban Berberoğlu answered questions about radionuclide treatments...

What are Radionuclide Treatments?

"Radionuclide therapy" can be summarized as a treatment using radiation-emitting substances. These treatments make a significant difference for patients with diseases such as prostate cancer and neuroendocrine tumors. They offer an additional treatment option for patients, different from chemotherapy and radiotherapy.

Nuclear Medicine Specialist Assoc. Prof. Dr. Kezban Berberoğlu appeared as a guest on the live broadcast of "A New Day with Çağla," hosted by Çağla Şikel on FOX TV.

In the Nuclear Medicine Department, we use radioactive substances for disease diagnosis. These include radioactive substances such as Technetium 99m and Fluorine-18. We add substances that are specific to the organ or the application we want to perform to the radioactive part. For example, if we want to perform a bone scan, we use a bone-specific agent, or if we want to image a tumor, we use substances like glucose that enter the tumor and show its vitality. Until now, in nuclear medicine, we have mainly discussed FDG PET-CT with F18-labeled glucose, a method we use in many types of cancer and which has become a routine practice in guidelines. However, as medical science progresses, we have seen that we are unable to visualize certain types of cancer effectively, such as prostate cancer. Studies have shown that imaging with a substance specific to the prostate, labeled with Gallium-68, has become the gold standard for imaging prostate cancer, its diagnosis, staging, and response to treatment. Similarly, in neuroendocrine tumors, where the FDG PET/CT method is not very effective, we can achieve a highly reliable imaging method by combining the Dota substance, specific to this tumor, with Gallium-68. By routinely using these methods in our clinic, we are able to make meaningful contributions to patient care.

It is very important to visualize diseases with appropriate radioactive substances, because if we label them with therapeutic radiation, we can treat them by administering targeted radiation through the bloodstream. In medicine, we refer to these imaging agents as "theranostic" agents. This can be considered the beginning of a groundbreaking era in medicine. Thanks to PET/CT studies with agents specific to diseases like prostate cancer or neuroendocrine tumors, we can diagnose the disease, stage it, and determine whether it is responding to treatment. Another key piece of information provided by these theranostic agents is whether the disease can be treated with radiation that is specifically labeled for it. By performing imaging on the patient to be treated, we can determine in advance whether the treatment will be beneficial. If we see lesions in a Gallium-68 PET-CT scan before treatment and can distinguish cancer cells, we know that radionuclide therapy will be effective.

What Agents are Available for Treatment?

We have two radioactive substances available for treatment: Lutetium-177 and Actinium-225. Both can be used in cancer treatment. Actinium-225 delivers pure alpha energy to the tumor, while Lutetium-177 enters the tumor cell with beta energy. Both radioactive substances damage the tumor cell's DNA, leading to its death. This treatment can be considered "internal" or "internal radiation therapy." The greatest advantage of this treatment is that the radioactive substance targets only the tumor and destroys it, minimizing harm to surrounding tissues and organs. Radionuclide treatments are smart and targeted therapies. After receiving these treatments, patients are discharged on the same day or the following day and do not emit significant radiation to their surroundings.

Targeted, Smart Treatments, that’s what they are...
Exactly. We can refer to these as "targeted radionuclide therapies" or "smart radiation therapies."

When Are These Treatments Applied?

Radionuclide treatments are typically used when radiotherapy and chemotherapy are not effective. Most of the time, treatments complement each other. In a multidisciplinary setting, where many branches work together and support each other, the timing of treatment is evaluated by the team and decided upon. Therefore, referring to these as "last-resort treatments" is not accurate. Treatments applied at the appropriate time are more successful. It is important for the entire team to be sensitive to ensure that the patient does not miss this opportunity.

How Common Are Radionuclide Treatments?

As publications on the success of these treatments increase, their prevalence is also rising. We see that the success rate is higher in teams with a well-established, multidisciplinary work culture. Personalized planning and appropriate patient follow-up increase the success of the treatment.

Which Patients Are These Treatments Applied To?

These treatments are used in patients diagnosed with hormone-resistant metastatic prostate cancer and neuroendocrine tumors. With these treatments, we see that, for example, patients with metastatic prostate cancer who were unresponsive to treatment start responding to the therapy, and their pain decreases. Since there are no side effects during this process, patients experience a comfortable period, which is especially important for elderly patients. It brings us great joy to take a patient off ineffective treatments that have side effects and allow them to live more comfortably. We often experience the satisfaction of a patient who comes for their first cycle in a wheelchair and walks in for the second cycle.

How Many Cycles of Radionuclide Treatment Are Applied?

The radiation dose required to eliminate the entire cancer is very high. We cannot administer it in a single dose because high doses would also kill normal cells. Therefore, we apply these treatments every 2 months, typically 4-6 cycles. Thanks to the low probability of side effects during the treatment and the good responses to the therapy, this method allows us to offer patients a comfortable treatment process, making meaningful contributions to their care.