Abstract

Introduction

Interstitial lung diseases (ILDs) are associated with the onset of lung cancer (LC).

Aims and objectives

We aimed to investigate the incidence rate, time to onset, and risk of the onset of LC in ILD patients.

Methods

We retrospectively evaluated consecutive ILD patients in 2008-2015. We investigated whether they developed LC until May 2021.
Results

Among 1070 ILD patients, 42 were excluded (patients diagnosed with LC by the time of the diagnosis of ILDs, 23; others, 19) and 1028 were included in the final analysis. Male was 671, median age was 68 years, smoking history was found in 551 (current, 94; former, 457) and 452 were diagnosed as idiopathic pulmonary fibrosis (IPF). The median observation period was 4.88 years (IQR: 2.07-7.49).

Sixty-four cases had LC (adenocarcinoma, 25; squamous cell carcinoma, 19; small cell carcinoma, 11; others, 9) and the median time to onset was 3.52 years (95% CI: 2.77-4.32). The incidences of LC were 1.27 cases per 100 person-years (IPF was 1.83 and non-IPF ILDs was 0.94, respectively). Univariable analysis showed male, age, smoking history and IPF were associated with the onset of LC. Multivariable analysis showed male and age were associated.

Conclusions

The incidences of LC in ILD patients were 1.27 cases per 100 person-years and the median time to onset was about 3.5 years. Male and age were significantly associated with the onset of LC.