An Overview of Theranostics and Its Applications in Cancer Treatment

Many exciting and promising medical treatments have emerged in recent years, especially in the field of oncology — the research, identification, and treatment of cancer. One treatment, theranostics, is the combination of diagnostics and therapeutics to diagnose and treat tumors.

In addition to saving time and money by combining the diagnosis and treatment, theranostics promotes patient-centered care by avoiding unnecessary therapies and coordinating care in a single procedure. For example, a patient can receive an imaging diagnosis and undergo treatment at the same time. Because of this, theranostics is sometimes described as a “P4 treatment” — predictive, preventive, participatory, and personalized to the patient.

The diagnostic component of theranostics involves imaging tests and/or agents that can identify cancerous tumors. Often, this includes PET scans. A PET (positron emission tomography) allows doctors to analyze the health of organs and tissues in the body. Before a PET scan is performed, radiotracers such as gallium-68 or scandium-44 are ingested by the patient or injected into the patient. Once inside the body, these radiotracers are absorbed by organs and tissues. Certain areas in the body, especially diseased tissues, absorb larger amounts of the radiotracer agents, which then show up as bright areas on PET scans.

PET scans and radiotracers are the most common tools used for a cancer diagnosis. However, other tests and tools, such as contrast agents, particulates, dual ultrasounds, optical imaging, and magnetic resonance imaging also are commonly used.

The therapeutic component of theranostics follows the diagnostic component. Typically, this stage involves the insertion of a drug molecule into a carrier system that directs the drug to a tumor, where the drug can attack and kill cancer cells. This may involve a radionuclide such as lutetium-177 (Lu-177) or yttrium-90 (Y-90). Each of these therapeutic agents binds to specific proteins found only in cancer cells and avoids healthy cells around the tumor.

When treating prostate cancer, for example, theranostics may include the identification of cancerous cells by a PET scan and then the delivery of high doses of targeted radiation. In cases of neuroendocrine tumors, theranostics can help send targeted radiation to cancerous cells in the nervous system. This radiation damages cells in the tumors, which may stop them from growing and even reduce their size. In both cases, a PET scan helps target the radiation so it avoids damaging healthy tissue.

As the field of theranostics has matured, specialty areas of study have arisen that explore the role of genetics in disease risk. These areas include pharmacogenetics, proteomics, and biomarker profiling.

Pharmacogenetics, which is useful for tailoring drug therapies in theranostics, focuses on variations in DNA sequences and genetic responses to treatment. Proteomics is the study of proteins encoded in the human genome to customize therapies. Biomarker profiling uses molecules, referred to as biomarkers, in the body that can indicate an underlying disease. For example, biomarkers may be produced by cancerous tissue or by the body itself in response to cancer, heart disease, or other diseases.

Going forward, theranostics may deliver personalized therapies by using more effective treatments at a lower cost to patients and with improved clinical outcomes.