Unlike chemotherapy, which is a more generalized treatment, targeted therapies are highly specialized. They treat the anomaly at the origin of tumor development, which is either molecular in nature (e.g., a mutation in the tumor, which is generally not hereditary) or a specific mechanism of tumor cell development. Targeted therapy is part of precision medicine.
Targeted therapies are mainly in administered orally, but they can also intravenous or subcutaneous.
Tumor cell multiplication consists of several stages, which are driven by signals from outside the cell (called growth factors) that trigger a chain reaction on the surface of, and then inside, the cell. This chain reaction leads to the division into two new cells, and then four, and so on. Targeted therapies are designed to stop this cell proliferation.
Targeted therapies can act at different levels:
By preventing the growth factor from attaching to the cell’s surface
Anti-angiogenic Treatments
Some cancers develop via a mechanism called tumor neoangiogenesis, whereby the tumor makes its own blood vessels. These vessels enable tumor vascularization, resulting in tumor growth and the dissemination of tumor cells into the patient’s bloodstream.
In this instance, anti-angiogenic (blood vessel growth prevention) treatments are used (either monoclonal antibodies by infusion or VEGF inhibitors).
Targeted therapies can be toxic to healthy cells which are significantly similar to target cells.
Side effects vary, but usually occur within the first weeks of treatment and can be easily managed.
Diarrhea
Targeted therapies often require a tissue biopsy or a surgical specimen to determine the targeted tumor abnormality.
Certain targeted therapies, in particular anti-angiogenics, are currently limited to certain tumor types where the vascularization process is identified as crucial to the tumor’s development.
