Impact of accurate diagnosis of interstitial lung diseases on postoperative outcomes in lung cancer

Abstract

Objective: The prognostic impact of interstitial lung disease (ILD) subclassification based on both high-resolution computed tomography (HRCT) scan findings and histopathological findings is unknown.

Methods: We retrospectively analyzed 104 patients who were diagnosed with clinical ILD according to HRCT scan findings and who underwent lung cancer surgery. Via an expert multidisciplinary discussion, we re-classified HRCT scan findings and validated the histopathological patterns of ILDs in lung specimens.

Results: There were several mismatches between HRCT scan findings and histological patterns. Moreover, 87 (83.7%) and 6 (5.8%) patients were diagnosed with definitive ILD and pathological non-ILD, respectively. Finally, 82 patients with idiopathic interstitial pneumonias (IIPs) were divided into the idiopathic pulmonary fibrosis (IPF) (n = 61) group and the other group (n = 21). The 5-year overall survival rate of the IPF group was significantly lower than that of the other group (22.8% vs 67.9%; p = 0.011). Sub-classification of IIPs was found to be an independent prognostic factor for overall survival in patients with lung cancer.

Conclusion: An accurate diagnosis of IIPs/IPF according to both HRCT scan findings and histological patterns is important for providing an appropriate treatment among patients with lung cancer who presented with clinical ILD.

Keywords: Air space enlargement with fibrosis; Interstitial lung disease; Lung cancer.

Fig. 1

a Diagram of patient classification by diagnosis with HRCT and pathological findings b Comparison of HRCT scan findings and histopathological patterns in lung specimens in patients with patterns other than UIP on HRCT findings. HRCT: high-resolution computed tomography, UIP: usual interstitial pneumonia

Fig. 2

Comparison of HRCT scan findings and histopathological patterns between patients diagnosed with IIP and those with pathological non-ILD. a–d. An IIP case. a The UIP pattern on HRCT: presence of honeycombing with sub-pleural and basal predominance. b Panoramatic view (scale bar: 1 mm) and low-magnification photograph (box) (Elastica van Gieson staining) showing dense fibrosis with architectural distortion in the form of honeycomb change. c Low-magnification photomicrograph showing predominant sub-pleural and para-septal distribution of fibrosis (scale bar: 1 mm, H & E). d Higher-magnification photomicrograph showing fibroblast foci (scale bar: 100 µm, H & E).e–h. A pathological non-ILD case. e Indeterminate UIP pattern on HRCT: multiple thin-walled cysts in the lower lobe. f High magnification photomicrograph showing mild fibrosis with centriacinar emphysema in the background (scale bar: 500 µm, Elastica van Gieson stain). g Panoramatic view (scale bar: 1 mm) and h low-magnification photomicrograph (box in Fig. 4 g) (Elastica van Gieson staining) showing a fibrous wall of bronchiolocentric cysts. HRCT: high-resolution computed tomography, IIP: idiopathic interstitial pneumonia, ILD: interstitial lung disease, UIP: usual interstitial pneumonia

Fig. 3

a Overall survival rate and b Disease-free survival rate of patients with IIP, ILD with a known cause, and pathological non-ILD. c Overall survival rate and b Disease-free survival rate of patients with IPF and other IIP groups. IIP: idiopathic interstitial pneumonia, ILD: interstitial lung disease, IPF: idiopathic pulmonary fibrosis