Targeted therapy or molecularly targeted therapy
is one of the major modalities of medical treatment. Targeted therapy is a cancer treatment that uses drugs. But it is different from traditional chemotherapy, which also uses drugs to treat cancer. Targeted therapy works by targeting the cancer’s specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. These genes and proteins are found in cancer cells or in cells related to cancer growth, like blood vessel cells.
It is helpful to know how cancer cells grow in order to better understand how targeted therapy works. Cells make up every tissue in your body. There are many different cell types, such as blood cells, brain cells, and skin cells. Each type has a specific function. Cancer starts when certain genes in healthy cells change. This change is called a mutation.
Genes tell cells how to make proteins that keep the cell working. If the genes change, these proteins change, too. This makes cells divide abnormally or live too long. When this happens, the cells grow out of control and form a tumor.
Researchers are learning that specific gene changes take place in certain cancers. So they are developing drugs that target the changes. The drugs can:
- Block or turn off signals that tell cancer cells to grow and divide
- Keep cells from living longer than normal
- Destroy the cancer cells
Types of targeted therapy
There are several types of targeted therapy:
- Monoclonal antibodies. Drugs called “monoclonal antibodies” block a specific target on the outside of cancer cells and/or the target might be in the area around the cancer. These drugs work like a plastic cover you put in an electric socket. The plug keeps electricity from flowing out of the socket.
Monoclonal antibodies can also send toxic substances directly to cancer cells. For example, they can help chemotherapy and radiation therapy get to cancer cells better. You usually get these drugs injected into a vein, or "intravenously" (IV).
- Small-molecule drugs. Drugs called “small-molecule drugs” can block the process that helps cancer cells multiply and spread. These drugs are usually taken orally as capsule or tablet. Angiogenesis inhibitors are an example of this type of targeted therapy. These drugs keep tissue around the tumor from making blood vessels. Angiogenesis is the name for making new blood vessels. A tumor needs blood vessels to bring it nutrients. The nutrients help it grow and spread. Anti-angiogenesis therapies starve the tumor by keeping new blood vessels from forming.