**Prediction of Anti-Cancer Drug-Induced Pneumonia in Lung Cancer Patients: Novel High-Resolution Computed Tomography Fibrosis Scoring**

**Hiroshi Gyotoku 1, Hiroyuki Yamaguchi 1,\*, Hiroshi Ishimoto 1, Shuntaro Sato 2, Hirokazu Taniguchi 1, Hiroaki Senju 1, Tomoyuki Kakugawa 1,3, Katsumi Nakatomi 1, Noriho Sakamoto 1, Minoru Fukuda 1,4, Yasushi Obase 1, Hiroshi Soda 5, Kazuto Ashizawa <sup>4</sup> and Hiroshi Mukae <sup>1</sup>**


Received: 7 March 2020; Accepted: 6 April 2020; Published: 7 April 2020

**Abstract:** Background and objective: Pre-existing interstitial lung disease (ILD) in lung cancer patients is considered a risk factor for anti-cancer drug-induced pneumonia; however, a method for evaluating ILD, including mild cases, has not yet been established. We aimed to elucidate whether the quantitative high-resolution computed tomography fibrosis score (HFS) is correlated with the risk of anti-cancer drug-induced pneumonia in lung cancer patients, even in those with mild pre-existing ILD. Methods: The retrospective single-institute study cohort comprised 214 lung cancer patients who underwent chemotherapy between April 2013 and March 2016. The HFS quantitatively evaluated the grade of pre-existing ILD. We extracted data regarding age, sex, smoking history, and coexisting factors that could affect the incidence of anti-cancer drug-induced pneumonia. Cox proportional hazard models were used to analyze the effects of the HFS and other factors on the risk of anti-cancer drug-induced pneumonia. Results: Pre-existing ILD was detected in 61 (29%) of 214 patients, while honeycombing and traction bronchiectasis were observed in only 15 (7.0%) and 10 (4.7%) patients, respectively. Anti-cancer drug-induced pneumonia developed in 19 (8.9%) patients. The risk of anti-cancer drug-induced pneumonia increased in proportion to the HFS (hazard ratio, 1.16 per point; 95% confidence interval, 1.09–1.22; *p* < 0.0001). Conclusions: The quantitative HFS was correlated with the risk of developing anti-cancer drug-induced pneumonia in lung cancer patients, even in the absence of honeycombing or traction bronchiectasis. The quantitative HFS may lead to better management of lung cancer patients with pre-existing ILD.

**Keywords:** lung cancer; interstitial lung disease; pulmonary fibrosis; radiology and other imaging
