Women's knowledge about breast cancer. Dimensions of knowledge and scale development.

Evidence suggests that knowledge about breast cancer may influence secondary prevention, care-seeking behavior, and participation in treatment decision-making. Yet few standardized measures of breast cancer knowledge are in existence. Using factor analysis, this paper describes the structure of women's knowledge about breast cancer and uses that structure to develop a measurement scale. Principal axis factoring and varimax rotation yielded a nine factor solution, which accounted for 59.3% of the common variance. Interpretation of the conceptual structure of these factors suggests that knowledge is organized around breast cancer treatment, misconceptions, risk factors, symptoms, menstruation, and prevalence. Considering only those items with factor loadings of .35 and greater, and including only those factors containing three or more items, a 16-item scale, which included four factor-based subscales covering knowledge about breast cancer treatment, misconceptions, risks, and symptoms was developed. Internal consistency reliability of the total scale and of the four subscales was high (alphas = .76-.95). Using chi square analysis, it was found that levels of knowledge on the total scale and on the treatment and symptom subscales are associated with age, education, income, and history of breast cancer. Knowledge on the misconceptions subscale was associated with age, education, and income. Knowledge on the risks subscale was associated with age and education. Issues of reliability and validity of the scale as well as directions for future research in this area are discussed.