P44.02 Mild Interstitial Pneumonia as a Risk Factor for Chemotherapy-Induced Acute Exacerbation of Interstitial Pneumonia in Patients with Lung Cancer

Abstract

Co-existing of interstitial pneumonia is reported to be a risk factor for chemotherapy-induced acute exacerbation of interstitial pneumonia in patients with lung cancer (LC). Although it has been recently demonstrated that co-existing of interstitial lung abnormalities on chest CT is associated with poor prognosis in patients with advanced non-small cell lung cancer, it has not been clarified the association between mild interstitial pneumonia and chemotherapy-induced acute exacerbation of interstitial pneumonia in detail. The goal of this study was to determine the clinical significance of mild interstitial pneumonia shadows on chest CT prior to the initiation of chemotherapy in patients with advanced LC. We retrospectively analyzed the patients with advanced LC treated with chemotherapy in our department from 2014 to 2016. Chest CT findings at the diagnosis of LC (baseline CT) were reviewed, and the patients were divided into three groups; 1) patients without interstitial pneumonia shadows, 2) with interstitial pneumonia shadows which was recognized (RIPS), and 3) with mild interstitial pneumonia shadows which had not been recognized (UMIPS) by treating physicians on baseline CT. The frequency of chemotherapy-induced acute exacerbation of interstitial pneumonia in patients with RIPS and UMIPS was compared with that of chemotherapy-induced lung injury in patients without interstitial pneumonia shadows. We included 112 patients with treatment naïve IIIB/IV LC in this study. The median age was 69 years (37-87 years), and the frequency of non-small cell lung cancer was 79%. The number of advanced LC patients with RIPS and UMIPS were 26 (23%) and 13 (12%), respectively. Chemotherapy-induced acute exacerbation of interstitial pneumonia was found in 7 (27%) RIPS and 2 (13%) UMIPS patients. On the other hand, chemotherapy-induced lung injury was occurred in only 3 out of 73 (4%) patients without interstitial pneumonia shadows on baseline CT. In patients with advanced LC, interstitial pneumonia shadows on chest CT, even in instances of mild shadows, should be considered as a risk factor of chemotherapy-induced acute exacerbation of interstitial pneumonia.