by CMRI | Published on 05/08/2020
Targeted therapy is a type of cancer which uses specific drugs to target cancer cells without causing any harm to the normal cells. Typically, these drugs target particular parts of cancer cells, like proteins or genes, which particularly promote the growth of cancer in the body. In some cases of cancer, target therapy proves very useful.
There are essentially two types of target therapies, including small molecule medicines and monoclonal antibodies. Some of the most common small molecule and monoclonal antibodies that are increasingly used to treat cancer include:
Hormone therapy: In this type of therapy, the focus is to stop the body from producing hormones that support the growth of breast and prostate cancer or keep the other healthy hormones from working efficiently.
Signal transduction inhibitors: These are the most common types of targeted therapies. In this particular treatment, the doctors restrict the signals which promote the cells to divide abnormally.
Gene expression modulators: This particular type of targeted therapy is more focused on changing the proteins that control how instructions in the cancer cells are carried out since they are abnormal.
Apoptosis inducers: Apoptosis is the natural process by which healthy cells die when they become old or damaged. However, in apoptosis inducer targeted therapy aims to find a way around this natural procedure of the body. This causes the cancer cells to follow the natural process of apoptosis.
Angiogenesis inhibitors: In this form of targeted therapy, the blood vessels that supply nutrients and oxygen to the cancer cells are blocked.
Immunotherapies: This particular treatment uses the body’s immune system to end cancer cells. In some cases, the immune system is made stronger to fight cancer cells. Alternatively, the immune system can be trained to recognise cancer cells and fight them.
That said, targeted therapy is best suited for cancers that have a target origin on which the treatment can be focussed. Hence, in many cases, the doctor would need to test the tumour to confirm if there are any targets. In most cases, the doctor conducts a biopsy to check for cancer. Targeted therapy is often given along with other treatments.
Targeted therapies are fairly new and can cause some significant complications. Some of the common issues include diarrhoea, live infections such as hepatitis, and modifications to the hair, skin and nails.
In some cases, the therapy causes skin issues, which are very difficult to bear. This is major because the targeted therapy attacks the growth elements, which promote healthy skin. That said, some of the major complications of targeted therapy include:
A rash that typically looks like acne on the areas such as the neck, face, chest, back and scalp. The rash can cause burning, stinging or itching. However, sometimes it can get infected. A feeling of sunburn even before any symptoms appear on the skin Increases sensitivity to sunlight
Cracks in the skin, making it look dry. This particularly happens in the feet and hands, making it hard for a person to use hands or feet properly
Sores on the finger and toenails that become swollen and painful Sores on the head, hair loss and often baldness.
Swollen and red eyelids often turn inward or outward. This can in many severe cases damage the cornea, the clear layers in front of the eye
To minimise complications, it is best to start using soaps and other skin products that are chemical-free and also do not have a strong fragrance. In cases, there are any skin changes, the patient must inform the doctor immediately to avoid infection. In case of severe skin infections, the patient might need to stop the targeted treatment.
Targeted therapies are not completely successful in all cases. They also have specific limitations. One limitation is that the cancer cells can eventually grow resistant to the therapy. Resistance can occur basically in two forms – first when the target modifies the mutation to block the interaction of target therapy. Alternatively, it can also find a new pathway to build the tumour, which does not rely on a target. Because of this limitation, targeted therapies are often considered to provide the best results when combined with a different treatment plan.
Another limitation of targeted therapy is that the drugs used in some specific targets are very hard to develop because of the structure of the target or the way it is engraved in the cell.
Targeted therapies are different from standard chemotherapies in many ways, including:
Targeted therapies base their treatment on certain molecular targets, which are linked to cancer. On the other hand, standard chemotherapies, act on the cells that rapidly divide.
Targeted therapies are specifically chosen or structured to interact with the target. However, chemotherapies aim to kill cancer cells.
Targeted therapies aim to block cell proliferation of the tumour cells, implying that they are cytostatic. However, standard chemotherapy is cytotoxic.
Overall, targeted therapies have become increasingly popular; however, the area is being researched to minimise complications and improve effectiveness. The applicability of the targeted therapy depends on the patient’s case and the final decision is taken by the healthcare professional.