Population-based estimates of the prevalence of family history of cancer among women

Objective: Family history of cancer is recognized as one of the most important risk factors in predicting personal cancer risk. Nevertheless, there are few published population-based estimates of family history prevalence by age categories. Methods: We used responses of female controls (n = 4,754) from the population-based Cancer and Steroid Hormone study (1980-1982) to estimate the frequency of family history of various cancers among female relatives. We determined the age- and race-specific prevalence of family history of breast, ovarian, endometrial, and other cancers in first-degree female relatives of women aged 20-54 years. To evaluate changes in reporting family history over time, we also analyzed responses of control women (n = 1,544) from the Women's Interview Study on Health (WISH) (1990-1992) to estimate the prevalence of family history of breast cancer. Results: The prevalence of a first-degree family history of breast, ovarian, endometrial, and cervical cancers was 6.4% (95% CI 5.7-7.1%), 1.1% (0.8-1.4%), 3.5% (3.0-4.0%), and 2.1% (1.7-2.5%), respectively. Among first-degree female relatives, the prevalence of family history of colon, lung, and thyroid cancers was 2.4% (2.1-2.9%), 1.5% (1.2-1.8%), and 0.5% (0.3-0.7%), respectively. The prevalence of family history of breast and colon cancers increased significantly with respondent's age. Similar results for family history of breast cancer were obtained from an analysis of responses from the WISH. Conclusions: In addition to providing a point of reference for research and health policy, these results may be of interest to providers who care for female patients because of the usefulness of information about family history of cancer for assessing lifetime risk of cancer.