Imaging of Oncologic Treatment-Related Pneumonitis: A Focused Review on Emerging Issues of Immune Checkpoint Inhibitor Pneumonitis, From the Special Series on Inflammation.

Treatment-related pneumonitis represents a major challenge in oncology patients undergoing therapy, and imaging plays an essential role in detection, diagnosis, and monitoring of pneumonitis in these patients. Among various types of pneumonitis from different kinds of cancer treatments, immune checkpoint inhibitor (ICI)-related pneumonitis has been recognized as an important topic in the radiology and oncology communities since 2015, given the increasing clinical indications for ICI therapy in patients with cancer. Moreover, clinical applications of ICIs continue to advance rapidly with novel combination approaches, leading to further emerging challenges. This focused review describes the current knowledge about ICI pneumonitis and discusses several newly emerging issues involving recurrence and flare of ICI pneumonitis, as well as involving pneumonitis from new combination approaches including ICI with epidermal growth factor receptor (EGFR) inhibitors and ICI with radiotherapy. The article concludes with a summary of unmet needs in the care of patients with ICI pneumonitis as well as of future directions in the advancement of knowledge about ICI pneumonitis and patient care for ICI pneumonitis. Given the proven multifaceted value of imaging in ICI pneumonitis, radiologists will remain central in the ongoing multidisciplinary journey to further understand and overcome this challenging toxicity for patients with cancer.