Predictive Role of Baseline Peripheral Lung SUVmax on PET/CT for Immune-Related Pneumonitis and Adverse Events in...

Immune checkpoint inhibitors (ICIs) offer durable responses in lung cancer patients lacking actionable mutations or with resistance to prior therapies. However, predicting their efficacy and associated immune-related adverse events (irAEs), such as severe pneumonitis, remains a clinical challenge. This study investigated the predictive value of positron emission tomography/computed tomography (PET/CT)-derived metabolic parameters for pneumonitis and other irAEs in lung cancer patients treated with ICIs.

We retrospectively analyzed 151 patients with advanced non-small cell lung cancer (NSCLC) who received ICIs as first-line treatment, either as monotherapy or in combination. Pre-treatment PET/CT was used to measure SUVmax at the primary tumor, tumor-uninvolved peripheral lung, and metastatic sites. Pneumonitis and irAEs were assessed using clinical and radiological findings.

Pneumonitis, severe pneumonitis (grade ≥3), and irAEs occurred in 26.5%, 19.9%, and 37.1% of patients, respectively. A peripheral SUVmax cutoff of >1.1 significantly predicted pneumonitis (area under the curve [AUC] = 0.720, p <0.001). High peripheral SUVmax was associated with higher rates of pneumonitis (42.9% vs. 12.3%, p <0.001), severe pneumonitis (31.4% vs. 9.9%, p=0.001), and irAEs (46.4% vs. 29.5%, p=0.038). In multivariate analysis, high peripheral SUVmax independently predicted pneumonitis (odds ratio [OR]: 4.621; 95% confidence interval [CI]: 1.868-11.431; p=0.001), severe pneumonitis (OR: 2.848; 95% CI: 1.043-7.779; p=0.041), and irAEs (OR: 2.509; 95% CI: 1.114-5.504; p=0.022).

Baseline peripheral SUVmax on PET/CT may serve as a noninvasive biomarker for predicting immune-related pneumonitis and other irAEs in NSCLC patients receiving ICIs, supporting early risk identification.