One of the most important advancements in cancer treatments is Immunotherapy. It is a biologic therapy which uses your body’s own immune system to fight cancer by either stimulating it or revving it up to recognize and fight cancer. With decades of research beyond what we know about our immune system and its ability to recognize and attack foreign substances, this therapy has come into fruition quite recently.
The immune system is a pack of organs, special cells and tissues that aids in safeguarding one’s body from infections or other diseases. The ability to discriminate body cells (self) from foreign materials (non-self) and attack or eradicate invaders are the fundamental properties of the immune system. Immune cells travel within one’s body to guard it from germs that may grow into infections and diseases.
So, in cancer, the immune system tries to prevent and curb the maturation of many cancers. Immune cells sometimes rest in and around tumors. These cells are known as tumor-infiltrating lymphocytes or TILs; this signifies that the immune system is responding to the tumor. Cancer patients, whose immune system reacts in this particular way, often do better than the others.
You might now wonder that if the immune system can fight from cancer cells, then why we need other treatments to cure cancer. Well, cancer cells have several ways to escape from the destruction done by the immune system as cancer cells may:
- Be genetic in nature that can make them less visible to the immune system.
- Contain proteins on their surface that could turn off immune cells.
- Convert the normal cells around the tumor so they interfere with how the immune system responds to the cancer cells.
Hence, to ensure that the immune system reacts in a better way against cancer, it is supported by immunotherapies. Different kinds of immunotherapies can be put in use to treat cancers:
- Immune Checkpoint Inhibitors– Immune checkpoints are considered to be a normal part of the immune system. They prevent an immune response from maturing so strongly that it damages healthy cells in the body. With the help of some drugs, called immune checkpoint inhibitors, the checkpoints proteins are blocked from binding with their partner proteins. This averts the “off” signal from being sent, letting the T cells fight cancer cells.
Cancers that are treated with immune checkpoint inhibitors: Breast cancer, Bladder cancer, cervical cancer, colon cancer, head and neck cancer, Hodgkin lymphoma, liver cancer, lung cancer, renal cell cancer, skin cancer, rectal cancer etc.
- Immune System Modulators– Immune-modulating agents are used to amplify the body’s immune response against cancer. Some immune-modulating agents are:
- Interleukins (ILs) Number of white blood cells, including killer T cells and natural killer cells are boosted up by IL-2. These increasing cells can double activate the immune system and promote it further to fight against the cancer.
- Interferons (INFs) Once these agents are active they may slow down the growth of cancer cells or even kill the cancer cells.
- BCG, stands for Bacillus Calmette-Guerin. Mainly used to treat bladder cancer.
Immunomodulatory drugs that stimulate the immune system are: Thalidomide, Lenalidomide, Pomalidomide, Imiquimod. Immune-modulating agents are commonly used to treat advanced stage cancers.
- T-Cell Transfer Therapy– To boost the immune cells, few most active cells against the cancer, are extracted from the tumor, which are then upgraded in the lab to fight even better. The two types of T-cell transfer therapies: Tumor-Infiltrating Lymphocytes Therapy and CAR T-Cell Therapy. Both the therapies involve a lab process, where some immune cells are collected from the body, grown in large numbers in the lab and then given back to the body via a needle directly in the vein. T-cell transfer therapy is also known as adoptive cell therapy, adoptive immunotherapy and immune cell therapy. These treatments are effective for people with melanoma and for other cancers, such as cervical squamous cell carcinoma and cholangiocarcinoma.
- Monoclonal Antibodies– These are targeted cancer therapies, which signify that they are designed to interact with certain targets. Antibodies are naturally formed by humans’ own body and aid the immune system in acknowledging germs that cause diseases, like bacteria and viruses plus spot them for destruction.
Immune system proteins (monoclonal antibodies), created in the lab, spot the cancer cells in the body and mark them for further destruction. Monoclonal antibodies are also known as therapeutic antibodies.
- Cancer Treatment Vaccines– The goal of these vaccines is to work against the cancer cells, not against something that may be the cause of cancer. These vaccines guide the immune system to recognize and respond to tumor-associated antigens (found in cancer cells) and kill cancer cells.
Cancer treatment vaccines could be made in three main ways.
- Made from one’s own tumor cells. They are customized and are quite unique to one’s cancer.
- Made from tumor-associated antigens that can be present in cancer cells of many people with a particular kind of cancer. This kind of vaccine is still experimental.
- Made from one’s own dendritic cells, which are a kind of immune cells. Dendritic cells vaccines energize the immune system to react to an antigen on tumor cells.
Side effects might vary from person to person. No certain time or stage has been mentioned by the doctors or nurses in this therapy. Whereas, some common side effects are listed here,
|Nausea or vomit||Muscle pain||Fatigue||Headache||Low or high BP|
Stimulation of the natural defenses of one’s immune system, so that it attempts to work harder and smarter to spot and attack accordingly against the disease, has completely revolutionized approach towards cancer. There is learning and development on how to combine immunotherapy with other therapies to improve outcomes for all patients.