Diagnosis and therapy in Teragnostics: a significant innovation in personalized and precision oncology medicine.

Teragnostics: diagnosis and therapies united toward personalized cancer medicine 

What is teragnostics?

We are used to thinking of diagnosis and therapy as two distinct moments, but innovations can come to change some ingrained ways of thinking and spread words that were previously used only among specialists. Teragnostics is one of them and can be translated as "making diagnosis and therapy together."

In clinical practice, Teragnostics consists of two phases:

- In the diagnostic phase, radioactive substances are used that are placed on tumor cells, making them visible on PET examination, precisely defining the tumor area;

- In the therapeutic phase, the substances, bound to the diseased cells, become targets for therapy with radiopharmaceutical molecules, which recognize them and selectively target them: once positioned, the radiopharmaceutical releases its radioactive charge, destroying the diseased cell.

This approach represents a significant innovation in precision medicine because it enables physicians to provide at an early stage, targeted treatments tailored to the specific needs of individual patients. It is currently used: 

- In oncology, where physicians, using molecular imaging techniques, can accurately detect prostate cancer cells and deliver targeted radiation therapy to affected tissues;

- In cardiovascular disease, to assess the risk of coronary artery disease. By using molecular imaging to identify specific biomarkers, physicians can identify patients at higher risk for cardiovascular events and provide targeted interventions to reduce their risk;

- In neurodegenerative disorders, to detect the presence of amyloid plaques in the brain, a hallmark of Alzheimer's disease. By using molecular imaging to identify these plaques, clinicians can make an early diagnosis and provide targeted treatments to slow the progression of the disease.

Neuroendocrine tumors

There are several molecules available for theragnostic purposes. Some are radioisotopes, administered as such, and which are capable of emitting beta particles and gamma particles simultaneously. The example is that of Iodine-131, a radioactive isotope of iodine used by the thyroid gland as a substrate for the synthesis of thyroid hormones. Thyroid cells, when well differentiated, are able to avidly concentrate iodine. In thyroid cancer patients, Iodine-131 can be administered after surgery to remove any remaining thyroid tissue, or to treat distant metastases. After administration, whole-body scintigraphy can be performed one week later to assess the stage of disease and verify that any neoplastic lesions are indeed able to concentrate the radiotracer. 

Neuroendocrine tumors frequently also arise in the gastro-entero-pancreatic tract, the so-called GEP-NETs. These neoplasms when well differentiated express on the cell surface receptors for somatostatin, a peptide capable of mediating specific cell growth processes. Cold analogs of somatostatin, i.e., nonradioactive, are used in the treatment of neuroendocrine tumors because of their ability to inhibit tumor growth. The analogs themselves can be radio-marked with Gallium-68, a PET tracer. Imaging makes it possible to assess whether a neuroendocrine tumor patient expresses appropriate amounts of somatostatin receptor on the cell surface and is thus a potential candidate for treatment with analogs. These molecules can be radio-labeled with Lutetium-177, a beta-emitting radioisotope, and in this way the patient can undergo radio-receptor therapy. Lutetium, like iodine also has gamma emission, and this allows us to perform imaging procedures here as well. Currently, treatment with Lutetium-177is reserved for metastatic, inoperable GEP-NET patients. The results obtained are extremely satisfactory: lutetium therapy has proven effective in limiting disease progression in these patients, increasing their survival rate. 

Teragnostics in radiology

Numerous contrast agents that also possess therapeutic properties are being developed:

- Some are designed to deliver at the level of the target, visualized with the images, the chemotherapeutic drug. Contrast media of this type consist of microbubbles that, as they accumulate in the hypervascularized tissues and break up on contact with the sound wave produced by the sonographer, release the active ingredient only in the area chosen by the sonographer; 

- Another approach, however, is to bind monoclonal antibodies, capable of hitting different molecular targets, to a nanoparticle. On the one hand, one is able to increase the affinity and specificity of the drug toward the target, and on the other hand to visualize the area affected by the treatment. Such particles can also be designed to release a chemotherapeutic only in the area where they bind, producing a local synergistic effect with antibody action. 

Future Perspectives.

The concepts of precision medicine and personalized medicine, aim to identify the patient as an individual and no longer as belonging to a category. Therefore, teragnostics becomes a particularly valuable application, as it allows precise characterization of the disease and directs the patient to a specific treatment. The expectation is to reduce disease progression, more than the therapies available to date. The hope is that what is invested in rare diseases and cancers will also benefit those with more widespread diseases in a short time. The advantage of this approach is to be able to select precisely and accurately, through imaging, those patients who can benefit from a specific treatment.