Theranostics combines targeted molecular imaging and radiation therapy to personalize cancer care, deploying diagnostic tracers to locate specific biological targets before delivering localized therapeutic isotopes to individual tumor lesions.
- Targeted Delivery: The technique pairs a diagnostic imaging agent with a therapeutic radioisotope to find and treat cancer cells simultaneously.
- Heterogeneity Mapping: Scans often reveal that different metastatic lesions within the exact same patient display varying molecular targets.
- Supply Chain Challenges: Most specialized radioisotopes used in these procedures must currently be imported, though domestic production projects aim to alter this reliance.
The core methodology of theranostics relies on identifying a biological characteristic present in high concentrations within tumor cells, Poder360 reported. Clinicians attach a recognizing molecule to a radioactive material to visualize the lesion via advanced imaging scans.
If the patient exhibits the targeted marker and meets specific clinical criteria, that exact biological signature guides a therapeutic isotope straight to the disease site. The oldest clinical application of this approach is radioactive iodine therapy for thyroid cancer, which physicians initiated back in the 1940s.
Modern applications extend beyond the thyroid to include specific neuroendocrine tumors and prostate cancer. For prostate malignancies, a primary focus is the prostate-specific membrane antigen, known as PSMA, which is a protein expressed in much higher amounts on tumor cells than on normal tissue.
Positron emission tomography scans show precisely which lesions capture a PSMA-directed molecule and measure the intensity of that uptake.
“The image today is essential to treatment. And it is not just having a diagnosis of prostate cancer that it will necessarily express PSMA,” Marcelo Queiroz stated in the Poder360 reporting.
Tumors classified under the same pathological heading do not always share identical cellular profiles. This divergence frequently occurs within a single individual, where certain metastases demonstrate much higher target expression than others.
Carmino Antônio de Souza, the principal investigator and a professor at the State University of Campinas, noted that certain tumors show significantly higher marker avidity than others.
This characteristic can also vary between different areas of the tumor,” Souza explained in the coverage by Poder360.
Despite the high degree of personalization in patient selection, the administered quantity of radioisotopes frequently follows standardized dosing schedules. This standardization remains an active point of debate within the clinical community.
Or would others need 8 cycles to reach the necessary amount of radiation?” Queiroz questioned in the Poder360 report.
Adjusting the administered radiation according to the specific energy absorbed by healthy tissues and tumor lesions is known as dosimetry. While specialized international centers utilize dosimetry protocols, tailoring every cycle based on individual radiation absorption is not yet a universal standard of care.
Scientific investigations are also exploring combinations of theranostics alongside immunotherapy and standard targeted agents.
| Tumor Type | Primary Molecular Target | Therapeutic Isotope | Protective Adjunct |
|---|---|---|---|
| Prostate Cancer | PSMA Protein | Lutetium-177 | Salivary Gland Monitoring |
| Neuroendocrine Tumors | Somatostatin Receptors | Lutetium-DOTATATE | Amino Acid Infusion |
Brazil currently imports a substantial portion of its required radioisotopes, which drives up costs and constrains supply stability.
Plans for the Brazilian Multipurpose Reactor, scheduled for completion by 2030 in the interior of São Paulo, aim to establish national self-sufficiency for isotopes such as lutetium-177.
During PSMA-directed therapies, salivary glands frequently absorb the radiopharmaceutical, which can lead to xerostomia, or reduced saliva production.
- Hospital Israelita Albert Einstein / Agência Einstein.
- Fundação de Amparo à Pesquisa do Estado de São Paulo (Fapesp).
