549P - Drug-induced interstitial lung disease in patients with non-small cell lung cancer treated with immunotherapy for postoperative recurrence: Evaluation of CT findings and histopathological findings of the background lung

Background

Interstitial pneumonia (IP) or interstitial lung abnormalities (ILA) is a risk factor for drug-induced interstitial lung disease (D-ILD) in immunotherapy. We usually evaluate interstitial pneumonia by CT findings without histopathological findings. We aimed to evaluate whether histopathological findings of the background lung in surgical specimens is correlated with development of D-ILD by immunotherapy in patients with postoperative recurrence.

Methods

Patients who were treated with immunotherapy or immunochemotherapy for first-line treatment of non-small cell lung cancer for postoperative recurrence from April 2017 to February 2023 were included. We retrospectively compared between characteristics of patients with and without D-ILD, including CT findings and histopathological findings of the background lung in surgical specimens.

Results

Among 32 included patients, we evaluated 27 patients whose surgical specimens were available. The median age was 72 years old, and 20 patients (74.1%) were male. Twelve patients (44.4%) had ILA on CT, and five patients (18.5%) had IP with usual interstitial pneumonia (UIP) pattern (two patients with UIP, one patient with probable UIP, and two patients with indeterminate for UIP) on pathology. Five patients (18.5%) developed D-ILD, including two patients with CTCAE grade 1, two patients with grade 2, and one patient with grade 5. Patients with D-ILD were significantly more likely to have ILA on CT than those without D-ILD (5/5[100%] vs. 7/22[31.8%], p<0.01). Although there was no significant difference, two of the patients with D-ILD had UIP pattern on pathology as compared with three of those without D-ILD (2/5[40％] vs. 3/22[13.6％] p=0.22). Four patients had both ILA on CT and UIP pattern on pathology, and two (50%) of these cases developed D-ILD.

Conclusions

In addition to chest CT findings, histopathological findings of the background lung in surgical specimens may be useful as predictors of D-ILD in immunotherapy.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

T. Tanaka: Financial Interests, Personal, Speaker, Consultant, Advisor: Boehringer Ingelheim GmbH, Mitsubishi Tanabe Pharma Corporation, Daiichi Sankyo; Financial Interests, Personal, Royalties: Bunkodo Co., Ltd., Gakken Inc. N. Katsurada: Financial Interests, Personal, Speaker, Consultant, Advisor: Bristol Myers Squibb Co., Ltd., Chugai Pharmaceutical Co., Ltd., MSD K.K. T. Nagano: Financial Interests, Personal, Invited Speaker: AstraZeneca K.K. M. Yamamoto: Financial Interests, Personal, Speaker, Consultant, Advisor: Chugai Pharmaceutical Co., Ltd. Chugai Pharmaceutical Co., Ltd., Chugai Pharmaceutical Co., Ltd., AstraZeneca K.K., Eli Lilly Japan K.K., Daiichi Sankyo, Taiho Pharmaceutical Co., Ltd. M. Tachihara: Financial Interests, Personal, Invited Speaker: Eli Lilly Japan K.K., Chugai Pharmaceutical Co., Ltd, AstraZeneca K.K, MSD K.K., Ono Pharmaceutical Co., Ltd., Bristol Myers Squibb Co. Ltd., Nippon Boehringer Ingelheim Co., Ltd., Pfizer Japan Inc., Daiichi Sankyo, Janssen Pharmaceutical K.K.; Financial Interests, Institutional, Research Grant: AstraZeneca K.K., Eli Lilly Japan K.K., Chugai Pharmaceutical Co., Ltd. All other authors have declared no conflicts of interest.