Women's perceptions of breast cancer risk: How you ask matters

Background. Some studies suggest that women dramatically overestimate the r isk of having breast cancer while others conclude that they underestimate i t. To understand better how women perceive the chance of getting breast can cer, the authors asked women to estimate the risk in several ways. Each wom an's answer was related to her actual risk. Methods. Women were randomly se lected from a registry of female veterans in New England. A mailed question naire asked each woman to estimate her ten-year risk of dying from breast c ancer as a number out of 1,000 ("_ in 1,000" perceived risk) and whether th is risk was higher than, the same as, or lower than that of an average woma n her age (comparative perceived risk). The woman was also asked to compare her risk of dying from breast cancer with her risk of dying from heart dis ease. Risk-factor data were collected so that each woman's actual risk of b reast cancer death could be estimated (actual risk). Results. 201 women had complete data. The median age of the respondents was 62 years (range 27-80 ), and 98% were high school graduates. Most women (98%) overestimated the i n 1,000" risk of breast cancer death-half by eightfold or more (interquarti le range, 4-36-fold overestimates). In contrast, only 10% of these women th ought that they were at higher risk than an average woman their age. Most c orrectly thought that their risk of dying from breast cancer was lower than their risk of dying from heart disease. The women's "_ in 1,000" perceived risks of breast cancer death were unrelated to their actual risks and had no significant agreement with an external benchmark of importantly "high ri sk" (i.e., met risk criteria for the Tamoxifen primary prevention trial). I n contrast, the women's comparative perceptions of being at low, average or high risk were related to actual risks and significantly agreed with the " high risk" benchmark. Most women not at importantly "high risk" correctly c lassified themselves; however, almost two thirds of "high risk" women miscl assified themselves as "average or lower than average risk." Conclusions. T he method used to elicit perceptions of risk matters. These women's respons es to the comparative questions showed that they "knew more" about their ac tual risks than their open-ended numeric responses suggested.