[Double primary malignant tumors involving a lung cancer]

Patients with multiple primary malignant tumors involving a primary lung cancer have been analyzed at our department in the Gunma University hospital. With reference to the lung cancer, three quarters of these patients were clinically in stages III or IV. The lung cancers were histologically classified into 26 epidermoid cancers, 14 adenocarcinomas, one large cell carcinoma, and one small cell carcinoma. Other primary cancers were 13 gastric cancers, 7 laryngeal cancers, 6 cervical cancers, 3 colon cancers, and other such cancers. Cases manifesting simultaneous cancers showing less than a one-year interval were 15 whereas 27 cases had double primary cancers with intervals of over one-year. Eleven patients had been given radiation therapy for their initial malignant tumor, but only two cases were considered to have incurred a radiation-induced lung cancer with a latent period of 5 and 12 years respectively.