The Philadelphia Pulmonary Neoplasm Research Project

A group of 6,136 older male volunteers reported every six months for ten years for photofluorograms of the chest and questionnaires; 121 developed primary lung cancer over the study period. One third of the cancers appeared to arise centrally and almost two thirds peripherally. Sixty percent were associated with prior nonmalignant abnormalities on x-ray films of the chest. The following observations were derived from 67 men whose tumors were detected within six months of a film read as negative for cancer. Both of two independent film readers suspected neoplasm in only 40% of the cases. Half the men with peripherally arising cancers were symptomatic compared to 86% of those with centrally arising tumors. There was a predilection for cancers to arise in the upper lobes, especially among the cancers arising as infiltrates and among adenocarcinomas. On retrospective review, the cancer was visible in the film prior to detection in 30% to 42% of cases, depending on the reviewer. Survival was better in men whose cancers arose peripherally than in those with centrally arising tumors.