Association of family history of cervical, ovarian, and uterine cancer with histological categories of lung cancer: the Iowa Women's Health Study.

A family history of cervical, ovarian, or uterine cancer has been shown to be associated with increased lung cancer risk among postmenopausal women. The present report examines the hypotheses that a family history of cervical cancer is positively associated with histological subtypes of lung cancer most strongly associated with smoking and that a family history of ovarian or uterine cancer are positively associated with risk of adenocarcinoma of the lung. Data are from the Iowa Women's Health Study, a prospective cohort study of 34,480 women ages 55-69 in 1986. Personal smoking histories, use of alcohol, and family history of selected cancers in first- and second-degree relatives were collected at baseline. Follow-up for cancer occurrence was achieved through the State Health Registry of Iowa. After baseline exclusions, a total of 343 incident lung cancers were identified in the cohort at risk through 1994. Women with a family history of cervical cancer in a first-degree relative had a multivariate-adjusted relative risk of lung cancer of 1.6 [95% confidence interval (CI): 0.98-2.6] compared to women without a family history. The risk was particularly high for malignancies most strongly associated with smoking (squamous, small cell, and large cell tumors; relative risk, 2.0; 95% CI, 1.1-3.7). Consistent with our hypotheses, a family history of ovarian cancer was associated with an approximately 2-fold increased risk (multivariate adjusted) of adenocarcinoma of the lung; the association with malignancies more strongly associated with smoking was inverse (relative risk, 0.6; 95% CI, 0.2-2.4). A family history of uterine cancer was not associated with adenocarcinoma, but there was a positive association observed for the most strongly smoking-associated histological types. These results suggest that a family history of cervical cancer is a modest independent risk factor for lung cancers most strongly associated with smoking, and a family history of ovarian cancer is a risk factor for adenocarcinoma of the lung.