FAMILY HISTORY OF CANCER AND RISK OF LUNG-CANCER AMONG LIFETIME NONSMOKING WOMEN IN THE UNITED-STATES

In a multicenter study of lung cancer in lifetime nonsmokers in the Un ited States, 646 female lung cancer patients and 1,252 population cont rols were interviewed regarding history of cancer in their first-degre e relatives. A 30% increased risk (95% confidence interval 0.9-1.8) wa s found for a history of respiratory tract cancer in parents or siblin gs after adjustment for exposure to environmental tobacco smoke (ETS) in adult life. Lung cancer, which represented approximately two thirds of the respiratory tract cancers, occurred more frequently in first-d egree relatives of lung cancer patients than in comparable relatives o f population controls (ETS-adjusted odds ratio = 1.29, 95% confidence interval 0.9-1.9). In particular, a significant threefold increased ri sk for lung cancer was associated with lung cancer diagnosed in mother s and sisters. The increased risk in relation to family history of lun g cancer was observed among parents and siblings who were smokers as w ell as in those who were nonsmokers. The association with family histo ry of lung cancer was strengthened when the analysis was restricted to adenocarcinoma of the lung (ETS-adjusted odds ratio = 1.50, 95% confi dence interval 1.0-2.2). However, there was no association between fam ily history of other cancers and risk of lung cancer in nonsmokers.