Immunotherapy has rapidly emerged as one of the most promising advancements in cancer treatment, offering new hope for patients where traditional treatments have failed. Unlike chemotherapy or radiation, which directly target cancer cells, immunotherapy empowers the body’s own immune system to recognize and destroy malignant cells. This approach has redefined how we treat certain types of cancers, leading to longer survival rates, fewer side effects, and in some cases, complete remission.
Immunotherapy is a form of biological therapy that enhances or manipulates the immune system to better identify and combat cancer cells. Cancer often develops when the body’s natural defense mechanisms fail to detect abnormal cell growth. Immunotherapy works by breaking through the "invisibility cloak" that many cancer cells use to evade immune detection, allowing the body’s natural defenses to attack them.
There are several types of immunotherapy currently used or being researched:
Each type offers a unique mechanism to stimulate or restore the immune response, and some are even combined with existing treatments for greater efficacy.
Several types of immunotherapy are currently used to treat cancer, each working in different ways to stimulate or support the immune system’s fight against cancer cells.
Checkpoint inhibitors are perhaps the most well-known form of immunotherapy. Our immune system uses checkpoints—molecules on certain immune cells—to prevent them from attacking healthy cells. However, cancer cells exploit these checkpoints to avoid being targeted.
Drugs like Pembrolizumab (Keytruda) and Nivolumab (Opdivo) block these checkpoints (such as PD-1/PD-L1 and CTLA-4) and allow immune cells to recognize and attack cancer cells. Checkpoint inhibitors have shown remarkable success in treating melanoma, non-small cell lung cancer, and renal cell carcinoma, among others.
Chimeric Antigen Receptor (CAR) T-cell therapy involves modifying a patient’s T-cells in a lab to express specific receptors that target cancer cells. Once modified, these supercharged T-cells are infused back into the patient, where they seek out and destroy cancer.
CAR T-cell therapy has been especially effective against certain blood cancers, like acute lymphoblastic leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL). Treatments like Kymriah and Yescarta have achieved remission rates as high as 80% in some patient groups.
Monoclonal antibodies are lab-made proteins that mimic the immune system’s ability to fight off harmful invaders. Some monoclonal antibodies, like trastuzumab (Herceptin) for HER2-positive breast cancer, bind directly to cancer cells, marking them for destruction. Others, known as conjugated monoclonal antibodies, are attached to chemotherapy drugs or radioactive particles, delivering toxic agents directly to cancer cells while sparing healthy tissue.
Unlike traditional vaccines that prevent diseases, cancer vaccines are designed to treat existing cancer by stimulating the immune system. An example is Provenge, used for metastatic prostate cancer, which teaches the immune system to attack prostate cancer cells. Research is ongoing into vaccines for pancreatic, breast, and brain cancers.
Cytokines are proteins that help modulate the immune system. Therapies using cytokines like interleukin-2 (IL-2) and interferon-alpha can boost immune cell growth and activity, improving the body's ability to fight cancer. While not as widely used today due to side effects, cytokine therapy laid much of the groundwork for modern immunotherapies.
One of the most significant advantages of immunotherapy is its potential for long-term remission, even after treatment ends. Traditional treatments like chemotherapy and radiation kill both healthy and cancerous cells, leading to numerous side effects. In contrast, immunotherapy is often more targeted.
While immunotherapy has made incredible strides, it isn’t without challenges.
One of the most significant barriers to widespread adoption of immunotherapy is its high cost. Unlike traditional treatments such as chemotherapy or radiation, immunotherapy often involves complex biological engineering, especially in personalized treatments like CAR T-cell therapy.
The transformative impact of immunotherapy is best illustrated through real-world success stories.
While immunotherapy is generally better tolerated than traditional treatments, it can still cause significant side effects, particularly when the immune system becomes overactive.
In some cases, the immune system may begin attacking healthy organs, leading to serious complications:
These side effects can often be managed with corticosteroids or other immunosuppressive drugs but require close monitoring.
The field of immunotherapy is rapidly evolving, with new treatments and approaches under development.
The next wave of treatments focuses on personalization. Neoantigen vaccines, which are custom-made for each patient based on their unique tumor mutations, are being tested in clinical trials.
Combining immunotherapy with other treatments like chemotherapy, radiation, or targeted therapy has shown promise. For example, combining checkpoint inhibitors with anti-angiogenic drugs in kidney cancer has improved survival rates.
These engineered antibodies are designed to bind to both cancer cells and immune cells simultaneously, bringing them into close proximity to enhance the immune response.
One of the biggest challenges is that many tumors develop resistance to immunotherapy. Researchers are exploring ways to re-sensitize tumors using different drug combinations or targeting additional immune pathways.
Deciding whether immunotherapy is a suitable treatment depends on various factors:
Related: Understanding Genetic Testing for Cancer Risk
A thorough discussion with an oncologist and possibly a genetic counselor is crucial in making an informed decision.
Immunotherapy has undoubtedly revolutionized cancer treatment, offering hope where traditional methods have fallen short. While it’s not a universal cure, its ability to deliver long-lasting remission and, in some cases, complete eradication of cancer is a testament to the power of the immune system when properly harnessed.
As research continues to evolve, the future holds promise for more personalized, effective, and accessible immunotherapies that will change the cancer treatment landscape even further.
