Predictive value of 18F-FDG PET/CT for acute exacerbation of interstitial lung disease in patients with lung cancer and interstitial lung disease treated with chemotherapy

We examined whether fluorine-18 2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) performed before chemotherapy could predict the onset of acute exacerbation of interstitial lung disease (AE-ILD) in patients with lung cancer and ILD treated with chemotherapy. Thirty-three patients with lung cancer and ILD who underwent 18F-FDG PET/CT and were treated with chemotherapy at Kumamoto University Hospital between April 2006 and March 2018 were retrospectively analyzed. The maximum standardized uptake value (SUVmax) of interstitial lesions was measured to quantify the background ILD activity. A prediction model of AE-ILD was developed using logistic regression analyses for the SUVmax, and receiver operating characteristic (ROC) curve analyses were conducted. Among the 33 patients, 7 experienced AE-ILD. The SUVmax of contralateral interstitial lesions was significantly higher in patients with vs. without AE-ILD (median SUVmax: 2.220 vs. 1.795, P = 0.025). Univariable logistic regression analyses showed that the SUVmax of contralateral interstitial lesions trended towards being significantly associated with the onset of AE-ILD [odds ratio: 8.683, 95% confidence interval (CI) 0.88–85.83, P = 0.064]. The area under the ROC curve of the SUVmax for predicting AE-ILD was 0.780 (95% CI 0.579–0.982, P = 0.025). The optimal cut-off value for SUVmax was 2.005, with sensitivity and specificity values of 0.857 and 0.769, respectively. The SUVmax of contralateral interstitial lesions in 18F-FDG PET/CT images might be useful for predicting the onset of AE-ILD in patients with lung cancer and ILD treated with chemotherapy.