[Clinical study of multiple primary cancers including lung cancer]

Out of a total of 506 lung cancers treated between 1977 to 1988, a total of 27 (5.3%) multiple primary cancers were uncovered. The patients consisted of 20 males and 7 females and their average age was 67 (48-81) years. The frequency seen in the histological type of patient with multiple primary cancers was the same as that seen in their background lung cancers. Twenty-one (78%) patients were smokers. Thirteen patients (45%) had a family history of cancer. Two cases had 3 family members who had a cancer history. The tumor DNA contents of 2 cases with multiple primary cancers were analyzed. In both cases, the DNA indices were found to differ between the first and the second cancer. Thus, it may be possible to identify multiple primary cancers by determining the tumoral DNA content.