Background Characteristics of Patients with Idiopathic Interstitial Pneumonia Associated with Lung Cancer

Abstract

Lung cancer was found in 10 (15%) of 67 patients with idiopathic interstitial pneumonia (IIP). In a retrospective study, 10 patients with IIP in chest roentgenograms were found among 440 patients with primary lung cancer. Of these 20 patients (10 IIP patients with lung cancer and 10 lung cancer patients with IIP findings), the average age 66 years, 15 (75%) were atypical cases previously proposed by us, and 19 (95%) were men. All these 20 patients smoked. In these patients, %VC, %TLC, %FRC and %RV were within normal range, but FEV_1.0% was low while it was not low in the IIP patients without lung cancer. %DL_CO/V_A was lower than the IIP patients without lung cancer. IIP-associated lung cancer was seen in the lower lobe in 12 (60%) patients. Histologically, 11 out of 20 (55%) were adenocarcinoma. Metastasis to other organs by lung cancer was observed in 10 (50%) even on the occasion of the first hospitalization. Thus, a close relation of IIP to lung cancer was suggested.