Immunotherapy represents a significant advancement in the treatment landscape for lung cancer. This approach harnesses the body’s own immune system to recognize and fight cancer cells. Unlike traditional treatments, immunotherapy works by enhancing the body’s natural defenses. This innovative therapy has expanded treatment options for many patients, including those with advanced-stage lung cancer, and contributed to improved survival rates for lung cancer patients in recent years.
How Immunotherapy Works for Lung Cancer
The immune system protects the body from foreign invaders, including cancer cells. However, cancer cells often develop ways to evade detection and destruction by the immune system. They can trick the immune system into thinking they are normal, preventing an immune response.
Immunotherapy drugs function by interfering with these evasion tactics. These treatments essentially “release the brakes” on the immune system, allowing it to identify and attack cancer cells more effectively. By blocking specific signals that cancer cells use to hide, immunotherapy helps restore the immune system’s ability to recognize the cancer as a threat.
This process involves targeting proteins on cancer cells or immune cells that regulate immune responses. Once these inhibitory signals are disrupted, immune cells, particularly T-cells, can become activated and launch an attack against the tumor. The goal is to stimulate a sustained immune response that can lead to tumor shrinkage or control disease progression.
Main Types of Immunotherapy for Lung Cancer
The most common types of immunotherapy for lung cancer are immune checkpoint inhibitors. These drugs target specific “checkpoints” that normally prevent immune responses from becoming too strong, which cancer cells exploit to suppress the immune system’s attack.
One major category is PD-1 inhibitors, which block the Programmed Death-1 (PD-1) protein found on immune T-cells. By blocking PD-1, these drugs prevent cancer cells, which often express the PD-L1 protein, from deactivating the T-cells. This allows the T-cells to remain active and continue their fight against the cancer. Examples include nivolumab and pembrolizumab.
Another significant type is PD-L1 inhibitors, which block the Programmed Death-Ligand 1 (PD-L1) protein directly on cancer cells. This prevents PD-L1 from binding to PD-1 on T-cells, disarming the cancer’s ability to evade immune surveillance. Both PD-1 and PD-L1 inhibitors essentially achieve the same outcome: reactivating the immune response against the tumor.
A third type is CTLA-4 inhibitors. These drugs target the Cytotoxic T-Lymphocyte-Associated protein 4 (CTLA-4), another checkpoint protein on T-cells that acts as an “off switch” for immune activity. By blocking CTLA-4, these inhibitors promote the initial activation and proliferation of T-cells.
Factors Guiding Immunotherapy Selection
Selecting the most suitable immunotherapy for lung cancer involves a personalized approach, as no single “best” option fits all patients. The choice is determined by several factors, which medical teams carefully consider. These considerations ensure the treatment aligns with the specific characteristics of the patient’s cancer and overall health.
One significant factor is the type of lung cancer; treatments can differ for non-small cell lung cancer (NSCLC), which accounts for most cases, and small cell lung cancer (SCLC). Within NSCLC, the specific histology, such as adenocarcinoma or squamous cell carcinoma, can also influence decisions.
Biomarkers play a crucial role, particularly the expression level of PD-L1 on tumor cells. Higher levels of PD-L1 expression often correlate with a greater likelihood of response to PD-1 or PD-L1 inhibitors. This biomarker helps predict how effective certain immunotherapy drugs might be for an individual patient.
Tumor genetics, including the presence of specific driver mutations, also guide treatment selection. While immunotherapy does not directly target mutations, the presence or absence of certain genetic alterations can influence whether immunotherapy or a targeted therapy is the preferred initial approach. A patient’s overall health, performance status, and previous treatments are also important considerations. These elements collectively help oncologists tailor the most appropriate treatment plan.
What to Expect During Immunotherapy Treatment
Undergoing immunotherapy for lung cancer typically involves intravenous (IV) infusions in an outpatient setting. The specific drug, dosage, and frequency of treatments vary depending on the type of immunotherapy and the patient’s individual treatment plan. Sessions might be scheduled every two, three, or four weeks.
Patients often experience a range of side effects, which differ from those associated with chemotherapy because immunotherapy activates the immune system rather than directly killing cancer cells. Common side effects can include fatigue, skin rashes, itching, and flu-like symptoms. These are generally manageable and often milder than traditional chemotherapy side effects.
A unique aspect of immunotherapy is the potential for immune-related adverse events (irAEs). These occur when the activated immune system mistakenly attacks healthy organs or tissues. IrAEs can affect various parts of the body, including the lungs (pneumonitis), colon (colitis), liver (hepatitis), and endocrine glands (thyroiditis).
It is important for patients to promptly report any new or worsening symptoms to their medical team. Early identification and management of irAEs are crucial to prevent severe complications. The medical team will provide detailed instructions on monitoring and managing side effects throughout the treatment course.