Immunotherapy has become the primary treatment for patients with various types of cancer, offering the potential to extend their survival. Typically, immunotherapy is administered until disease progression or unacceptable toxicity, or up to the recommended maximum duration in patients without disease progression. Recently, the criteria for the use of PD-1/PD-L1 immune checkpoint inhibitors, such as pembrolizumab (Keytruda), nivolumab (Opdivo), durvalumab (Imfinzi), and atezolizumab (Tecentriq), have been modified by the Croatian Health Insurance Fund (HZZO). According to the new criteria, the duration of treatment is limited to a maximum of 24 months for all drugs except for adjuvant treatment in melanoma (nivolumab, pembrolizumab), where the duration is limited to one year. The optimal duration of immunotherapy in cancer treatment is still not well-established. Guidelines from ESMO (European Society for Medical Oncology) and NCCN (National Comprehensive Cancer Network) recommend a duration of two years in the first-line setting. However, most clinical trials have arbitrarily limited the duration to two years, and there is a lack of definitive clinical studies to determine the optimal duration. The main efficacy outcomes monitored in clinical studies with immunotherapy are progression-free survival (PFS) and overall survival (OS). Some evidence suggests that patients treated with immunotherapy for one year may have a shorter PFS compared to those treated for a longer period. However, data from real-world studies indicate that longer treatment duration may lead to better survival rates, with the risk of disease relapse after treatment cessation depending on the initial response achieved. The decision to continue or stop immunotherapy after two years is still a matter of debate among healthcare professionals. Some argue that stopping treatment after achieving a complete or partial response might be appropriate, especially considering the potential toxicity and costs associated with long-term treatment. Prospective clinical trials are currently underway to explore early discontinuation criteria and biomarkers that could help quantify the risk of disease recurrence. These studies aim to determine the optimal duration of treatment and indications for discontinuation while taking into account patient response and other factors. The choice between continuous immunotherapy and a fixed duration is challenging, as toxicity and costs play significant roles. While most side effects occur within the first 6-9 months of treatment, some patients may experience severe toxicity later on. Additionally, the financial burden of long-term immunotherapy could strain healthcare systems and impact access to care. In conclusion, the optimal duration of immunotherapy remains uncertain, and an arbitrary cutoff of two years may not be appropriate for all patients. Individualized treatment decisions should consider patient response, toxicity, quality of life, and the potential for long-term disease control. Further research is needed to identify the best approach to immunotherapy duration and its impact on overall survival. Literature:
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