Risk factors for radiation pneumonitis in lung cancer patients with subclinical interstitial lung disease after thoracic radiation therapy

Hongyu Wu,Fangjuan Li,Hui Liu,Yaping Xu,Shixiong Liang

doi:10.1186/s13014-021-01798-2

Abstract

BackgroundPrevious studies have found that patients with subclinical interstitial lung disease (ILD) are highly susceptible to developing radiation pneumonitis (RP) after thoracic radiation therapy. In the present study we aimed to evaluate the incidence of and risk factors for RP after thoracic intensity-modulated radiation therapy in lung cancer patients with subclinical ILD.MethodsWe retrospectively analyzed data from lung cancer patients with subclinical ILD who were treated with thoracic intensity-modulated radiation therapy with a prescribed dose of ≥ 50 Gy in our institution between January 2016 and December 2017.ResultsEighty-seven consecutive lung cancer patients with subclinical ILD were selected for the study. The median follow-up period was 14.0 months. The cumulative incidence of grades ≥ 2 and ≥ 3 RP at one year was 51.0% and 20.9%, respectively. In the multivariate analysis, a mean lung dose ≥ 12 Gy was a significant risk factor for grade ≥ 2 RP (p = 0.049). Chemotherapy with gemcitabine in the past, V5 ≥ 50%, and subclinical ILD involving ≥ 25% of the lung volume were significantly associated with grade ≥ 3 RP (p = 0.046, p = 0.040, and p = 0.024, respectively).ConclusionMean lung dose is a significant risk factor for grade ≥ 2 RP. Lung cancer patients who have received chemotherapy with gemcitabine in the past, V5 ≥ 50%, and those with subclinical ILD involving ≥ 25% of lung volume have an increased risk of grade ≥ 3 RP in lung cancer patients with subclinical ILD.

Highlights

Radiation pneumonitis (RP) is a common complication of radiotherapy for lung cancers
The inclusion criteria were as follows: (1) patients diagnosed with lung cancer by histology or cytology; (2) interstitial lung changes on high-resolution Computed Tomography (HRCT) images before radiotherapy and chemotherapy; (3) Karnofsky performance status scale ≥ 70 and ability to endure intensity-modulated radiation therapy (IMRT) at a total dose of the equivalent dose in 2.0 Gy/(fraction per day) (EQD2) ≥ 50 Gy; (4) age ≥ 18 years; (5) no other serious medical conditions; (6) Radiation therapy (RT) with concurrent or sequential chemotherapy; (7) no thoracic radiation therapy (TRT) received previously; (8) thoracic CT images available for evaluation before and after TRT; (9) follow-up time of more than six months for patients without radiation pneumonitis (RP); and (10) patients were inoperable
None of the patients had been diagnosed with interstitial lung disease (ILD) clinically or via lung biopsy prior to receiving chemotherapy or radiotherapy

Summary

Introduction

Radiation pneumonitis (RP) is a common complication of radiotherapy for lung cancers. Subclinical interstitial lung disease (ILD) has a higher incidence in patients with lung cancer than in the general population [10]. Previous studies found that patients with subclinical ILD were more susceptible to developing RP after thoracic radiation therapy (TRT) [10,11,12,13,14,15,16]. Previous studies have found that patients with subclinical interstitial lung disease (ILD) are highly susceptible to developing radiation pneumonitis (RP) after thoracic radiation therapy.

Objectives

Methods

Results