Immunotherapy is a revolutionary approach to cancer treatment that harnesses the power of the body’s own immune system to fight cancer. It aims to stimulate or enhance the immune system’s natural ability to recognize and destroy cancer cells, offering a targeted and personalized approach to cancer care. This method can be used alone or in combination with other cancer treatments. Immunotherapy is a standard treatment for certain cancers, and is currently being explored in clinical trials for many others.
How the Immune System Fights Cancer with Immunotherapy
The immune system is a complex network of cells, tissues, and organs that defends the body against infection and disease. It includes organs like lymph glands and the spleen, as well as specialized cells like white blood cells. Typically, the immune system can identify and eliminate abnormal cells, preventing cancer development. However, cancer can arise when:
- The immune system is weakened, lacking sufficient white blood cells to detect and eliminate cancer cells.
- Cancer cells emit signals that suppress the immune response, preventing attack.
- Cancer cells evade detection or hide from the immune system.
Immunotherapy aims to counteract these mechanisms by boosting the immune system’s ability to recognize and attack cancer cells. Several types of immunotherapy treatments exist, each working in different ways to achieve this goal.
Who is a Candidate for Immunotherapy?
The suitability of immunotherapy as a treatment option depends on several factors, including:
- The specific type of cancer
- The stage of the cancer’s progression
- Prior cancer treatments received
Pre-treatment Testing
Before starting certain immunotherapies, tests may be conducted on cancer cells or blood samples. These tests identify specific proteins or genetic markers that indicate whether the treatment is likely to be effective. This is not always necessary for all immunotherapies, and your oncologist can advise you on whether this applies to your specific case.
To analyze cancer cells, a biopsy sample is required. Existing tissue samples from previous biopsies or surgeries may be used.
Types of Immunotherapy
Immunotherapy treatments are diverse, and some can be categorized in multiple ways due to their multifaceted mechanisms. Therefore, you may encounter the same treatment being referred to by different names.
For instance, checkpoint inhibitors, a form of immunotherapy, are also classified as monoclonal antibodies or targeted treatments.
Consult your cancer specialist to discuss:
- Whether immunotherapy is appropriate for your situation
- The goals of the treatment
- The process involved and potential side effects
Monoclonal Antibodies (mAbs)
Antibodies, naturally present in our blood, are crucial for fighting infections. Monoclonal antibody therapies are laboratory-produced antibodies that mimic the function of natural antibodies. The term “monoclonal” signifies that each therapy comprises numerous copies of a single type of antibody.
MAbs target and attach to specific proteins on the surface of cancer cells. Various MAbs are available for cancer treatment, each operating differently, sometimes with multiple mechanisms, which include triggering the immune system or directly assisting the immune system in attacking cancer.
Checkpoint Inhibitors
Cancer cells can sometimes deactivate immune cells, preventing them from recognizing and attacking the cancer. Checkpoint inhibitors are monoclonal antibodies that reactivate the immune system, enabling it to recognize and attack cancer cells.
These inhibitors prevent proteins on cancer cells or T cells from activating the “stop” signal, effectively turning the immune system back on, allowing T cells to proliferate and attack the cancer.
Cancer Treatment Vaccines
Vaccines can empower the immune system to recognize and combat cancer cells. These vaccines, similar to those used against infectious diseases, are designed to identify proteins present on specific cancer cells, thus enabling the immune system to target and destroy those cells.
Talimogene laherparepvec (T-VEC) is a treatment used for some melanoma skin cancer patients. It utilizes a modified, weakened form of the cold sore virus that is engineered to replicate within cancer cells and destroy them. This modified virus also stimulates the immune system to recognize and attack cancer cells.
Researchers continue to explore and develop new vaccines to enhance the immune system’s ability to fight cancer.
Cytokines
Cytokines are a group of proteins within the body that play a vital role in enhancing the immune system.
Interferon, a type of cytokine, is produced naturally by the body. Scientists have developed synthetic versions of interferon to treat myeloproliferative disorders, such as polycythaemia vera (PV) and essential thrombocythaemia (ET).
CAR T-Cell Therapy
This therapy involves modifying the genes of a patient’s T cells to help them identify and kill cancer cells. T cells are a type of white blood cell. The genetic modification of T cells is a form of genetic engineering.
CAR T-cell therapy is available as a treatment option for certain individuals, including children with leukemia and adults with lymphoma. It may also be offered as part of a clinical trial for patients with other types of cancer.
