[A clinical study of pulmonary tuberculosis in lung cancer patient]

We have reviewed 442 patients with lung cancer. There were 323 male patients with a mean age of 65.8 yr and 119 female patients with a mean age of 66.0 yr. Histological types of lung cancer were squamous cell carcinoma 177 patients (40.0%), adenocarcinoma 167 (37.8%), small cell carcinoma 75 (17.0%), large cell carcinoma 17 (3.8%) and undifferentiated carcinoma 6 (1.4%). When lung cancer was diagnosed, 55 patients (12.5%) showed tuberculous lesions on the initial chest X-ray film. The majority of these tuberculous lesions were old changes, but only one with cavitary lesion was confirmed to be active. Although there was no statistical significance, the incidence of squamous cell carcinoma was higher in the 55 patients with tuberculous lesions than in the remaining 387 patients without ones. In the present study, five patients developed active pulmonary tuberculosis while on a therapy of lung cancer. All of these five patients were male and they had advanced lung cancer on admission. The diagnosis of active tuberculosis was made by autopsy in two patients and by culture--positive after death in two. Only one patient was identified to have active tuberculosis by broncho-alveolar lavage. Three of 5 patients showed old tuberculous lesions on the initial chest X-ray film, but all of five patients showed caseoinfiltrative shadows when active tuberculosis occurred. In addition, the prevalence of active pulmonary tuberculosis was significantly higher in the patients with old tuberculous lesions (5.6%: 3 out of 54 patients) than in those without ones (0.52%: 2 out of 387 patients). Finally, all of the five patients died. The causes of death were lung cancer in three patients, both pulmonary tuberculosis and lung cancer in one and pulmonary tuberculosis in one.