Assessing Radiological Response to Immunotherapy in Lung Cancer: An Evolving Arena

In the past decade, immune checkpoint inhibitors (ICIs) have entered the treatment landscape of non-small-cell lung cancer, signalling a paradigm shift within the field characterized by significant survival benefits for patients with advanced and metastatic disease, and especially those with non-targetable genetic oncogenic driver mutations. However, the shift towards immune-based treatments has created new challenges in oncology. Atypical immunotherapy response patterns, including pseudo-progression and hyperprogressive disease, as well as immune-related adverse events have generated the need for new methods to predict patient response to treatment. Hence, new versions of the traditional Response Evaluation Criteria for Solid Tumors (RECIST) have emerged to help characterise with better accuracy radiological findings concerning patient response classification to immunotherapy. This review discusses response evaluation criteria relevant to unique radiological findings observed in patients treated with immunotherapy for non-small-cell lung cancer.