Using the impact of event scale to evaluate distress in the context of genetic testing for breast cancer susceptibility.

The data obtained with two forms of the Impact of Event Scale were compared, one referring to a BRCA1/2 test result (IES-T) and another to cancer (IES-C). The sample consisted of 272 women with a family history suggestive of a BRCA1/2 mutation who underwent genetic testing and received results: noncarrier, carrier, or inconclusive. Globally, mean scores on the IES-C form were higher than those obtained on the IES-T form. Among carriers of a BRCA1/2 mutation, mean scores on the two forms were similar and agreement was good, as measured by the intraclass correlation coefficient (.83; 95% 95% CI=.72, .91). Agreement between the forms was poor to fair among noncarriers (ICC= .38; CI= .15, .57) and women with an inconclusive result (ICC= .40; 95% CI= .26, .52). Having had cancer increased total scores but had little influence on agreement between scores on forms. These findings highlight the importance of carefully selecting the form of the Impact of Event Scale in the context of genetic testing for breast cancer susceptibility.