Through research, cancer care is changing for the better. Treatment is becoming less about the type of cancer and more about creating tailored treatment plans unique to the genetic makeup of each patient’s specific tumor. While chemotherapy, radiation, and surgery have been primary forms of cancer treatment for decades, with better understanding of the human body, researchers have discovered ways to harness the power of the immune system to fight cancer with breakthroughs that now effectively treat lung, breast, blood, colorectal, bladder, kidney cancers, and more. This is known as immunotherapy, a rapidly growing component of cancer treatment.
In recognition of Immunotherapy Awareness Month in June, here are five things to know about immunotherapy and cancer.
1. What is immunotherapy?
Immunotherapy is a type of treatment that boosts the body’s own defense mechanisms to fight diseases at the cellular level. By using substances either naturally produced or developed in a laboratory, this form of treatment enhances the immune system’s response to fight cancerous cells.
2. How does immunotherapy help treat cancer?
When the immune system encounters unknown entities, such as viruses or bacteria, it recognizes them as a threat and kicks into fight mode until the body is healthy again. However, for diseases like cancer, the body has a harder time recognizing these cells as a threat, as they are descended from normal cells.
Immunotherapy activates certain parts of a patient’s immune system to recognize a marker on cancerous cells, which helps the body to recognize and attack those cells. This limits the cancer’s ability to spread by stopping or slowing its growth.
Given as an IV, oral, topical, or intravesical (directly into the bladder), immunotherapy can also protect normal cells, which differs from chemotherapy which does not differentiate as effectively between cancer cells and normal cells.
3. Are there different types of immunotherapies used to treat cancer?
Most immunotherapy treatments fall into five primary categories.
• Monoclonal antibodies: Cancer cells have proteins on the cell’s surface called antigens. Monoclonal antibodies target tumors by attaching themselves directly to the tumor’s specific antigen proteins. Types of monoclonal antibodies, such as immune checkpoint inhibitors, disrupt the cancer cell’s defense against the immune system, allowing the body to limit the cancer growth and destroy cancerous cells.
• Adoptive cell therapy: This therapy directly harvests lymphocytes – a type of white blood cell in the immune system that makes antibodies, helps kill tumor cells, and controls immune responses – from the patient. Harvested lymphocytes are modified in a lab to be sensitized to the cancer cells, multiplied, and then re-administered to the patient as a form of immunotherapy against their cancer. One example is chimeric antigen receptor T-cell therapy (CAR-T cell therapy) – a personalized treatment in which a patient’s immune cells are removed from the body, genetically reprogrammed, and infused back into the body to identify and attack their cancer.
• Cancer vaccines: Cancer vaccines are given to those diagnosed with cancer to help increase the body’s ability to fight tumor growth, limit the spread of cancer cells, and reduce the risk of recurrence. These vaccines also may be tailored to a patient’s immune system – combining tissue from a patient’s individual cancer with cancer-fighting substances. Many types of cancer vaccines are currently in development, such as peptide and dendritic cell vaccines, which induce specific immune responses that can selectively eliminate target cells.
• Non-specific immunotherapies (cytokines): These therapies boost the immune system and increase its response to cancer cells in a more general way. Small proteins that are critical in controlling the growth and activity of other immune system cells and blood cells – called cytokines – activate a broad array of immune cells with the potential benefit of fighting cancer. While these can be administered as primary treatment, most are given in combination with other treatments such as chemotherapy and radiation.
• T-cell promoters: Some therapy drugs restore or promote T-cell activity, which helps overcome the defenses of cancerous tumor cells.
4. Who qualifies for immunotherapy?
Immunotherapy has proven to be an effective treatment for certain types of cancer which have been resistant to chemotherapy and radiation treatment. The decision to treat cancer using immunotherapy can depend on the type, biomarkers, stage of cancer, and other pre-existing medical conditions. For example, immunotherapy may not be recommended for a person with active autoimmune disease on treatment.
5. What are the benefits and side effects of immunotherapy in cancer treatment?
Immunotherapy can be used alone or in combination with other types of treatments. This therapy also can train the immune system to remember cancer cells, resulting in longer-lasting remissions. Additional benefits of immunotherapy include:
• Stimulating a patient’s immune system to work harder or smarter to attack cancer cells.
• Boosting the patient’s immune system with man-made immune system proteins.
• Overcoming cancer cell defenses against the human immune system.
All patients respond differently to immunotherapy, with possible side effects that can range from mild to severe, transient to irreversible. The key to controlling these is understanding what to expect and talking about the various risk factors with your physician. Side effects can include:
• Skin rashes
• Stomach, intestinal, or liver issues
• Shortness of breath
• Imbalanced thyroid hormone levels
• Flu-like symptoms
If you have been diagnosed with cancer, your treatment team will discuss which immunotherapies might benefit you and develop a customized plan based on your tumor and stage, baseline health conditions, and goals of treatment.
Shail Dalal, M.D., is a hematologist and medical oncologist at Texas Oncology–Palestine Cancer Center, 3415 South Loop 256, Palestine, Texas. For more information, visit TexasOncology.com.