Imaging Findings of Response and Complications after Targeted Therapy and Immunotherapy

Immunotherapy and targeted therapy has revolutionized cancer treatment. Immunotherapy involves medications, such as immune-checkpoint inhibitors (ICIs) that target different points of the immune pathway. Targeted therapy is a class of drugs that target specific genetic mutations in cancer cells, such as epidermal growth factor receptor mutations. However, the response to these therapies varies among patients and complications can arise. Imaging plays a crucial role in assessing the response to these therapies. The Response Evaluation Criteria in Solid Tumors criteria provide specific definitions for different response categories, which are crucial in evaluating the response to chemotherapy or targeted therapy. Additional response criteria have also been developed for evaluating response in patients receiving immunotherapy. The complications span a wide spectrum, from immune-mediated pneumonitis and sarcoid-like reactions to more complex conditions involving multiple organ systems. The severity of these reactions can vary from asymptomatic to life-threatening and typically occur within weeks or months after starting the therapy. This review underscores the complexity of responses and complications associated with both immunotherapy and targeted therapy in cancer treatment. It highlights the need for a comprehensive understanding of these phenomena for the accurate diagnosis and management of complications, ultimately aiming to improve patient outcomes.