Immunotherapy represents a type of cancer treatment that uses the body’s immune system to combat cancer. Unlike conventional treatments, immunotherapy has emerged as a significant modality, a distinct strategy for managing cancer. It helps the immune system become more effective at fighting cancer by boosting its components or teaching it to recognize previously overlooked cancer cells.
How Immunotherapy Influences Survival
Immunotherapy influences survival by activating and enhancing the immune system’s cancer-fighting ability. While chemotherapy directly attacks rapidly dividing cells, including healthy ones, immunotherapy focuses on empowering the patient’s own immune response. This distinction can lead to more targeted effects and fewer side effects.
The core mechanism involves “releasing the brakes” on immune cells, enabling a stronger attack against cancer. This activation can lead to durable responses, a sustained reduction in tumor burden. Durable response in immunotherapy correlates with improved overall survival and quality of life for patients.
Immunotherapy can lead to long-term remission or even cure. By training the immune system to “remember” cancer cells, it can target and eliminate them if they return, for sustained control. This memory function provides a protective mechanism against relapse, a benefit conventional therapies lack. Achieving long-term control by stimulating the immune system represents a new approach to managing cancer progression.
Interpreting Survival Statistics
Understanding survival statistics for cancer and immunotherapy involves recognizing them as population-level averages rather than individual predictions. These statistics, such as median overall survival and 5-year survival rates, provide a general picture of patient outcomes. Median overall survival, for example, indicates the point at which half the patients in a study are still alive. These figures do not determine how long any single patient will live, but rather reflect broad trends observed across many individuals.
The advent of immunotherapy has significantly altered these statistics for various cancer types. For instance, in metastatic melanoma, where median survival was once approximately 6.5 months, the emergence of immune checkpoint inhibitors has dramatically increased survival. Long-term data from trials show that about half of patients with metastatic melanoma treated with a combination of nivolumab and ipilimumab experienced cancer-free survival for 10 years or longer.
Immunotherapy has led to improved survival rates across different cancers. For patients with advanced non-small cell lung cancer, pembrolizumab increased the 5-year survival rate to over 15%, compared to 5.5% before its use. Similarly, nivolumab has improved 5-year survival rates for early-stage lung cancer, with 80% of those treated surviving after five years. These cases demonstrate immunotherapy’s impact on long-term survival for previously challenging cancers.
Individual Factors Affecting Outlook
Several factors influence a patient’s individual outlook with immunotherapy. The specific type and stage of cancer play a substantial role, as cancers and their stages respond uniquely. For example, melanoma, lung cancer, kidney cancer, and certain lymphomas respond positively. A patient’s overall health and performance status also affect their ability to tolerate treatment and respond effectively, such as sarcopenia and systemic inflammation.
Specific biomarkers can predict immunotherapy response. Programmed death-ligand 1 (PD-L1) expression, microsatellite instability-high (MSI-H), and tumor mutational burden (TMB) are key biomarkers. Tumors with high TMB produce more neoantigens, aiding immune recognition and attack. MSI-H tumors also have a higher mutational burden, resulting in increased neoantigen production and a stronger immune reaction.
Previous treatments can also impact immunotherapy’s effectiveness; prior treatments often lead to a poorer response. The tumor’s response to immunotherapy indicates individual outlook. This response can manifest as a partial reduction in tumor size, stable disease, or even progressive disease.
Some patients may experience pseudoprogression, where the tumor appears to grow or new lesions emerge due to immune cell infiltration before shrinking. This phenomenon, occurring in under 10% of cases, highlights the need for careful monitoring and can lead to delayed responses. This complex interplay emphasizes the importance of a personalized approach to cancer treatment.