Technique uses the same molecule that identifies and treats cancer – 09/05/2023 – Health

The same molecules used to diagnose a tumor in exams such as scintigraphy and PET-CT are also being used in the treatment of the disease.

Baptized “theranostic”, this concept that combines the words therapy and diagnosis is the central theme of the Brazilian Congress of Nuclear Medicine, which will take place at the end of September, in Pernambuco.

Traditionally, this medical specialty uses radiopharmaceuticals, which are molecules combined with radioactive elements that are captured by organs or lesions, both for diagnosis and treatment of diseases.

When injected into the patient, they not only reveal the shape, but also the functioning of organs such as the heart, brain, thyroid, kidneys, liver and lungs, which makes it possible to identify conditions ranging from pulmonary embolism to heart attacks, kidney diseases, cancer and Alzheimer’s disease.

In addition, these radiopharmaceuticals are also used in the treatment of conditions such as hyperthyroidism and thyroid cancer, among others.

In the case of the “theranostic”, the same molecule is linked to two types of radioactive elements, with different objectives: one makes the diagnosis and the other is used in the treatment of the disease.

“Based on the imaging test, we can screen the patient and find out whether he will respond to treatment”, explains nuclear physician Lilian Yamaga, from the Imaging Department at Hospital Israelita Albert Einstein.

Recently, the technique has shown promising results in patients with prostate cancer who have not responded to other treatments.

In these cases, the process begins with the diagnosis, which uses a molecule present in greater quantity in the membrane of the cells of that tumor, known as PSMA. This molecule is linked to a radioactive material and is captured by the tumor, revealing its characteristics and location. Then, based on this information, the same molecule is associated with another radioactive element that has the power to destroy cancer cells.

“The advantage is being able to take the radiation to the exact location of the tumor anywhere in the body and in the necessary amount, even in cases where the tumor is spread out, seeking to avoid reaching healthy cells as much as possible”, explains Paulo Rosado, scientific director of the Sociedade Brazilian Institute of Nuclear Medicine.

“It can cause fewer side effects than other therapies, it increases the quality of life and survival of these patients, becoming one more weapon in the treatment arsenal.”

According to Yamaga, it is a systemic treatment, well targeted, capable of taking the right medicine to the exact location. “We got good results in cases that didn’t respond well to standard cancer treatment.”

With the discovery of new molecules, the development of increasingly personalized therapies for different types of tumors is expected. It is important to note that the amount of radiation used in diagnostic tests is very small. Both tests and treatments with radiopharmaceuticals are safe procedures, with rare adverse events.

“Our challenge now is to expand access to these tests and treatments, as not all are included in the procedures approved by the SUS [Sistema Único de Saúde] and in supplementary health, as well as prioritizing investments to guarantee the production of the necessary inputs”, says Rosado.