Clinical and CT imaging features of immune checkpoint inhibitor-associated pneumonia / 中华放射学杂志

ABSTRACT

Objective:To explore the clinical and CT imaging features of immune checkpoint inhibitor-associated pneumonia (CIP) and to improve the early diagnostic ability of CIP.Methods:From June 1, 2020 to October 31, 2021, the clinical data and chest CT images of 2 067 patients with advanced malignant tumor treated with immune checkpoint inhibitor (ICI) in the First Medical Center, Chinese PLA General Hospital were retrospectively analyzed. Patients with CIP were enrolled according to the guidelines for CIP diagnosis, and the incidence, time from the start of medication to the onset of CIP, medication cycle, imaging features, imaging patterns, CT grade and outcomes were analyzed. χ 2 test was used to compare the incidence of CIP in patients with or without basic lung disease. Results:Among 2 067 patients with malignant tumors treated with ICI, 67 patients developed CIP, the incidence of CIP was 3.2%. The incidence of CIP was significantly different between 386 patients with basic lung disease (7.00%, 27/386) and 1 681 patients without basic lung disease (2.4%, 40/1 681) (χ 2=21.32, P<0.001). The time from the start of medication to the onset of CIP was 7-367 d (median 52 days), and the duration of medication was 1-12 cycles (median 2 cycles). The imaging features of CIP presented as ground glass opacities in 54 cases (80.6%), solid nodules in 26 cases (38.8%), consolidations in 25 cases (37.3%) and irregular reticular opacities in 24 cases (35.8%). The main radiologic pattern was organizing pneumonia (OP, 34 cases, 50.7%), and followed by diffuse alveolar damage (DAD) pattern (14 cases, 20.9%). According to CT grading, there were 26 cases in low risk grade, 17 cases in moderate risk grade and 24 cases in high risk grade. Of 43 low-and medium-risk grade cases, 25 were OP pattern, accounting for 58.1%, and among 24 high-risk grade patients, 13 were DAD pattern, accounting for 54.2%. Forty-three of the 52 patients were initially untreated, of which 23 patients progressed, 17 had lesion shrinkage, and 3 had resolution, and relapsed in 8 cases after resolution or drug withdrawal. Conclusions:The imaging manifestations of CIP are mainly ground glass opacities, nodules, consolidations, and irregular reticular opacities. The radiologic patterns are mainly OP and DAD. OP is the most common pattern in low-moderate risk grade CIP and DAD is the most common pattern in high risk grade CIP. Patients with basic lung disease are more likely to get CIP.