Pneumoconiosis-related Lung Cancers Preferential Occurrence from Diffuse Interstitial Fibrosis-type Pneumoconiosis

It has been reported that patients with pneumoconiosis occasionally have a diffuse interstitial fibrosis (DIF) that resembles interstitial pneumonia, but little is known about the relation between pneumoconiosis-associated DIF and the risk of lung cancer. In the present study, we evaluated the incidence of DIF by chest CT and its contribution to lung cancer in 563 patients with nonasbestos pneumoconiosis. Fifty-five (10%) of the 563 patients had DIF. Pneumoconiosis with DIF had an exceedingly high concurrence of lung cancers when compared with pneumoconiosis without DIF (29 [53%] of 55 versus 78 [15%] of 508, p < 0.001). Squamous cell carcinomas (SCCs) of the lung from pneumoconiosis with DIF exclusively comprised peripheral-types, as compared with SCCs from pneumoconiosis without DIF (13 [100%] of 13 versus 33 [72%] of 46, p = 0.03). In addition, lung cancers arose frequently from the area of DIF in pneumoconiosis with DIF (20 [74%] of 27). Furthermore, our pathologic examination revealed that dysplasias...