Subpleural honeycombing on high resolution computed tomography is risk factor for fatal pneumonitis

Postoperative interstitial pneumonitis is a life-threatening complication after lung cancer surgery. We conducted this study to identify risk factors for postoperative interstitial pneumonitis in patients with no clinical evidence of interstitial lung disease.

We retrospectively studied patients who underwent lung cancer resection. The characteristics of patients were analyzed by reviewing their clinical and surgical records and preoperative chest high-resolution computed tomographic scans. Postoperative interstitial pneumonitis was defined as acute severe hypoxemia accompanied by radiographic diffuse interstitial infiltrates of the lung with no apparent cause within a few weeks after surgery.

From 2002 through 2005, 651 patients were evaluated, operated on, and managed by the same team. Postoperative interstitial pneumonia developed in 7 patients (7 of 651, 1.1%). Five of these patients had local, but not diffuse, dorsal subpleural honeycombing occupying three or more segments in both lower lobes on high-resolution computed tomography (CT honeycombing). During the same period, 46 patients had CT honeycombing. The incidence of postoperative interstitial pneumonia was 10.9% (5 of 46) among patients with CT honeycombing and 0.3% (2 of 605) among those without CT honeycombing. Four of the 7 (57%) patients with postoperative interstitial pneumonia died of respiratory failure. Mortality among the patients who had postoperative interstitial pneumonia as well as CT honeycombing was 80% (4 of 5); in contrast, none of the patients without CT honeycombing died. Multivariate analyses showed that the presence of CT honeycombing and prolonged operation time were significant risk factors.

Subpleural honeycombing on high-resolution computed tomography is a significant predictor of postoperative interstitial pneumonia in asymptomatic patients who undergo resection for lung cancer.