Previous pulmonary infection in lung cancer: A review

Abstract

Recent autopsy investigations of lung cancers arising in tuberculosis scars, infarcts and in pneumonia-infected alveoli seem to confirm the connexion, predicted on the basis of histological evidence, between lung cancer and previous injury. The hypothesized correlation emphasizes host factors in lung cancer and physical rather than chemical carcinogenic mechanisms. Statistical evidence is, however, contradictory. Four retrospective studies of previous lung infections in lung cancer patients fail to demonstrate a consistently significant excess of previous disease in lung cancer patients or, when an excess has been found, to distinguish the portion attributable to smoking or to pre cancer-diagnosis symptoms from that which may play a direct causal role in lung cancer. A prospective study of British veterans of the First World War reported a two-fold lung cancer increase in veterans with chronic bronchitis over a matched sample, whereas a similar study of American veterans failed to show a significant increase among soldiers hospitalized with pneumonia during the 1917 influenza epidemic. The immediate need is for replication of the statistical studies with better controls and larger numbers.