Background: Idiopathic interstitial pneumonias (IIPs) are diffuse parenchymal lung disease of unknown etiology. Among IIPs, idiopathic pulmonary fibrosis (IPF) is the most frequent subtype. IPF is characterized by the accumulation of activated fibroblasts and extracellular matrix within the parenchyma. IPF is associated with pathologic and radiologic pattern of usual interstitial pneumonia (UIP). There are several possible underlying mechanisms linking lung cancer and IPF, however, many of them are still unknown. The purpose of this study is to reveal the clinicopathological characteristics of lung cancers patients with concomitant IPF.

Materials and Methods: The clinical and pathological data of lung cancer patients with IPF who underwent surgical resection of lung cancer between 2001 to 2016 at our institution were analyzed. We defined IPF as IIPs with UIP pattern, based on the chest CT scan and pathological findings. Mutations of EGFR (L858R point mutation and exon19 deletion), AKT1, BRAF, EGFR, KRAS, MEK1, NRAS, PIK3CA, and PTEN were analyzed.

Result: A total of 37 patients’ data of lung cancer with concomitant IPF was collected. Two patients had metachronous lung cancers. Thus, we analyzed 39 lung cancers from 37 patients. Based on the radiographic findings, 33 (84.2%) of the available 38 tumors arose from the fibrotic legion, which were mainly observed in peripheral region. The frequency of EGFR mutation was detected in 1 (2.6%) of 39 lung cancers. As control, we had EGFR mutation profile of 583 lung cancer without IPF. For this population, EGFR mutation was found in 164 (28.1%) of 583 cases. There was a significant difference in EGFR mutation between lung cancers with or without IPF (p = 0.0001). Among other examined genes in 16 tumors, one PIK3CA mutation was found.

Conclusion: The lung cancer with IPF mainly arouse from fibrotic lesion. The frequency of EGFR mutation was less common in lung cancers with IPF than those without IPF. Our result suggests that molecular profile of lung cancer with IPF is different from that without IPF.

Citation Format: Kota Araki, Kazuhiko Shien, Shunsaku Miyauchi, Akihiro Miura, Yuta Takahashi, Eisuke Kurihara, Yusuke Ogoshi, Kei Namba, Ken Suzawa, Hiromasa Yamamoto, Shuta Tomida, Junichi Soh, Masakiyo Sakaguchi, Shinichi Toyooka. Clinicopathological characteristics of lung cancer patients with concomitant idiopathic pulmonary fibrosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1410.