What is Immunotherapy?
Immunotherapy is a revolutionary type of cancer treatment that works by harnessing the power of a patient’s own immune system to fight cancer. Unlike other treatments that attack cancer cells directly, immunotherapy stimulates or “unleashes” the body’s natural defenses, helping immune cells to recognize and destroy malignant cells more effectively.
The immune system is the body’s natural defense against disease and is designed to identify and eliminate foreign invaders like bacteria and viruses, as well as abnormal cells like cancer cells. However, cancer cells can be very clever and develop ways to “hide” from the immune system or to switch it off, allowing them to grow unchecked. Immunotherapy drugs are designed to interfere with these hiding mechanisms. Over the past decade, immunotherapy has become a standard of care and a fourth pillar of cancer treatment, alongside surgery, radiation therapy, and chemotherapy, for a growing number of cancer types.
How Does Immunotherapy Work? A Focus on Checkpoint Inhibitors
There are several types of immunotherapy, but the most widely used and successful class of drugs are known as immune checkpoint inhibitors.
The immune system has natural “checkpoints”—proteins on the surface of immune cells that act like brakes to prevent the immune response from being too strong and attacking the body’s own healthy tissues. Cancer cells can take advantage of these checkpoints by producing proteins that bind to the immune cells, effectively hitting the brakes and shutting down the immune attack against them.
Immune checkpoint inhibitors are drugs that block this interaction. By physically blocking either the protein on the cancer cell or the checkpoint protein on the immune cell, these drugs “take the brakes off” the immune system. This allows the immune cells, particularly T-cells, to recognize the cancer cells as abnormal and to launch a powerful and sustained attack against them. In Turkish oncology centers, these therapies are a key part of the treatment arsenal for many advanced cancers.
The Role of the Medical Oncologist
In Turkey, the medical oncologist is the specialist who manages immunotherapy treatment. They are responsible for determining if a patient is a suitable candidate for this therapy, selecting the appropriate drug, and monitoring the patient throughout the course of treatment.
The medical oncologist’s role includes:
- Patient Selection: Evaluating the cancer type, stage, and specific biomarkers to decide if immunotherapy is a viable option.
- Treatment Planning: Determining the specific drug, dose, and schedule of infusions.
- Monitoring for Response: Assessing how the cancer is responding to the treatment through regular physical exams and imaging scans (like CT or PET scans).
- Managing Side Effects: Identifying and managing the unique side effects associated with immunotherapy, which are different from those of chemotherapy.
Biomarkers: Predicting Response to Immunotherapy
Not every cancer responds to immunotherapy. Researchers have identified certain features, or “biomarkers,” within a tumor that can help predict which patients are more likely to benefit from this treatment. Before starting therapy, a sample of the patient’s tumor tissue is often tested for these biomarkers.
One of the most common biomarkers is a protein called PD-L1 (Programmed Death-Ligand 1). This is one of the proteins that cancer cells can use to switch off immune cells. If a tumor has a high level of PD-L1 expression, it often indicates that the cancer is actively using this pathway to hide from the immune system, and therefore, it is more likely to respond to a checkpoint inhibitor that blocks this pathway. Other more complex biomarkers, such as microsatellite instability (MSI-high), may also predict a strong response to immunotherapy.
How Immunotherapy is Administered in Turkey
Immunotherapy with checkpoint inhibitors is typically administered as an intravenous (IV) infusion in a hospital’s outpatient chemotherapy or infusion unit.
The process is generally straightforward:
- Administration: The drug is infused into a vein over a period of about 30 to 90 minutes.
- Schedule: Unlike daily chemotherapy cycles, immunotherapy infusions are typically given less frequently. A common schedule might be once every two, three, four, or six weeks.
- Setting: The treatment is given in a comfortable and safe setting, supervised by specialized oncology nurses who monitor the patient during the infusion for any immediate reactions. Patients are typically able to go home the same day.
Understanding the Side Effects of Immunotherapy
Because immunotherapy works by stimulating the immune system, its side effects are very different from those of chemotherapy. Instead of causing hair loss or low blood counts, the side effects of immunotherapy are the result of an over-activated immune system, which can sometimes mistakenly attack the body’s own healthy tissues. These are known as “immune-related adverse events.”
These side effects can affect almost any organ in the body, but they most commonly involve:
- Skin: Rashes or itching.
- Gastrointestinal Tract: Diarrhea or inflammation of the colon (colitis).
- Endocrine Glands: Inflammation of glands like the thyroid, pituitary, or adrenal glands, which can affect hormone levels.
- Lungs: Inflammation of the lungs (pneumonitis), which can cause coughing or shortness of breath.
- Liver: Inflammation of the liver (hepatitis), which can be detected with blood tests.
Most of these side effects are mild to moderate and can be managed effectively, often with medications like steroids to suppress the immune system. It is crucial for patients to report any new or unusual symptoms to their medical oncologist immediately, as early management is key.
The Goals of Immunotherapy
Immunotherapy can be used with different goals depending on the cancer type, stage, and overall treatment plan.
- First-Line Treatment for Advanced Cancer: For many metastatic cancers, such as melanoma, lung cancer, and kidney cancer, immunotherapy (often combined with chemotherapy or another immunotherapy drug) is now the standard initial treatment.
- Second-Line or Subsequent Treatment: For some cancers, immunotherapy is used if the disease comes back or stops responding to initial treatments like chemotherapy.
- Adjuvant or Neoadjuvant Setting: In some cases, immunotherapy is being used after (adjuvant) or before (neoadjuvant) surgery to reduce the risk of recurrence.
A unique feature of immunotherapy is its potential to produce durable, long-term responses. For a subset of patients, immunotherapy can lead to a long-lasting remission where the cancer is controlled for many years.
Frequently Asked Questions
1. How is immunotherapy different from chemotherapy?
Chemotherapy works by directly killing rapidly dividing cells, which includes cancer cells as well as some healthy cells (like hair follicles), leading to its characteristic side effects. Immunotherapy works indirectly. It does not kill cancer cells itself; rather, it stimulates the body’s own immune system to do the job, leading to a very different set of potential side effects.
2. Is immunotherapy a treatment option for all cancer patients?
No. Currently, immunotherapy is approved and effective for specific types of cancer, and it is most often used for cancers that are advanced or have metastasized. The decision to use immunotherapy depends on the cancer type, its stage, and often the presence of specific biomarkers (like PD-L1) in the tumor.
3. What are immune-related adverse events?
These are the side effects caused by immunotherapy. They occur when the stimulated immune system mistakenly attacks healthy tissues in the body, causing inflammation. These can affect various organs, including the skin, colon, lungs, and hormone-producing glands. Most are manageable, but it is very important to report any new symptoms to the oncology team right away.
4. How do doctors in Turkey determine if immunotherapy is a good option?
The medical oncologist makes this determination based on several factors. This includes internationally recognized guidelines for the specific cancer type and stage. Additionally, they will often order laboratory tests on a sample of the tumor tissue to check for biomarkers, like PD-L1 expression, which can help predict the likelihood of a response to treatment.
5. How long does a patient receive immunotherapy treatment?
The duration of treatment can vary. For advanced or metastatic cancer, if the patient is responding well and tolerating the side effects, treatment can continue for up to two years, or sometimes longer, as long as it continues to be effective. In the adjuvant setting (after surgery), it is typically given for a fixed period, such as one year.
6. Is immunotherapy considered a cure for cancer?
While immunotherapy has been a major breakthrough, it is not a guaranteed cure. However, for a subset of patients with advanced cancer, it can lead to exceptionally durable, long-term remissions that can last for many years, which was very rare with previous treatments. For this reason, it has fundamentally changed the outlook for many types of advanced cancer.
7. Where is immunotherapy administered in a hospital?
In Turkish hospitals, immunotherapy infusions are typically given in the same specialized outpatient infusion units where chemotherapy is administered. These are comfortable, modern facilities staffed by oncology nurses who are experts in administering IV medications and monitoring patients.
