Health literacy and cancer risk perception: implications for genomic risk communication.

BACKGROUND: As new genomic technology expands the number of medical tests available to physicians and patients, identifying gaps in our understanding of how best to communicate risk is increasingly important. We examined how health literacy informs breast cancer survivors' understanding of and meaning assigned to recurrence risks yielded by genomic tests.
METHODS: Study participants were posttreatment female breast cancer survivors (N =163) recruited at a university breast cancer clinic. We assessed their health literacy (using REALM) and their interpretation of hypothetical recurrence risk results from a genomic test, presented in several verbal and numerical formats. Analyses controlled for women's objective recurrence risk, age, income, and race.
RESULTS: Women with lower health literacy gave higher mean estimates of recurrence risk for a hypothetical group of women with early-stage breast cancer than did women with higher health literacy (52% v. 30%, P < 0:001). Women with lower health literacy also gave more variable estimates in this and several other tasks. When making chemotherapy decisions using risks presented in verbal formats, decisions by women with lower health literacy were less sensitive to the difference between low and high recurrence risk. Ease of understanding of risk formats differed by health literacy.
CONCLUSIONS: Health literacy affected the meanings women assigned to recurrence risk when presented in certain formats. The greater variability in responding by women with lower health literacy supports the hypothesis that they have less precise mental representations of risk, but more research is needed to rule out other possible explanations.