Purpose: Family history guides cancer prevention and genetic testing. We sought to estimate the population prevalence of increased familial risk for breast, ovarian, endometrial, prostate, and colorectal cancers and hereditary cancer syndromes that include these cancers.
Methods: Using the 2005 California Health Interview Survey data, a weak, moderate, or strong familial cancer risk was assigned to 33,187 respondents. Guidelines were applied to identify individuals with hereditary breast-ovarian cancer and hereditary nonpolyposis colon cancer.
Results: Among respondents without a personal history of cancer, familial breast cancer was most prevalent; 7% had a moderate and 5% a strong familial risk. Older individuals and women were more likely to report family history of cancer. Generally, whites had the highest prevalence, and Asians and Latinos had the lowest prevalence. Among women without a personal history of breast or ovarian cancer, 2.5% met criteria for hereditary breast-ovarian cancer, and among individuals without a personal history of colorectal, endometrial or ovarian cancer, 1.1% met criteria for hereditary nonpolyposis colon cancer.
Conclusions: We provide population-based prevalence estimates for moderate and strong familial risk for five common cancers and hereditary breast-ovarian cancer and hereditary nonpolyposis colon cancer. Such estimates are helpful in planning and evaluation of genetic services and prevention programs, and assessment of cancer surveillance and prevention strategies.