Scar cancer of the lung: increase over a 21 year period.

In a review of 1,186 cases of lung cancer found amoung 7,629 autopsied cases over a 21 year period a total of 82 peripheral cancers related to scars were found, constituting 1% of the autopsied cases and 7% of the lung tumors. 15% of all lung tumors were peripheral (vs. bronchogenic) and the percentage rose from less than 7 in the time period of 1955 to 1960 to a little more than 23 in the 1970 to 1976 time period. 45% of all peripheral lung cancers originated in a scar. Less than 2% of all lung cancers were found associated with scars in the 1955 through 1959 time period. This increased to nearly 16% in the 1970 through 1975 time period. 72% of the scar cancers were adenocarcinomas and 18% were of squamous cell type. The rest were large cell undifferentiated carcinomas and none was oat cell or small cell type. Over three-quarters of these scar cancers were found in the upper lobes and more than half were related to infarcts. Less than a quarter were related to tuberculosis scars. No relationship was found between smoking habits and scar cancer.