Reliability of a statistical instrument for predicting BRCA1/BRCA2 genetic mutation carrier status

Concerns about breast/ovarian cancer susceptibility have resulted in increasing numbers of individuals seeking information about their risk of carrying genetic mutations. Statistical models have been developed to provide accurate predictions of an individual's probability of having a BRCA1/BRCA2 mutation. BRCAPRO is one such tool. The purpose of this study was to assess the reliability of BRCAPRO, and to compare it with two other commonly used models, for use in clinical counseling settings.; The theoretical framework is based on a conflict-theory model of decision-making developed by Janis and Mann (1977). This theory postulates that decisional conflict leads to psychological stress, and that providing individuals with useful information will help decrease their decision-making uncertainty.; Using a retrospective approach, a comparison was made between the BRCA1/BRCA2 mutation status of a tested patient and her predicted status using the BRCAPRO model. A convenience sample of 157 individuals seen at two different cancer risk clinics was used. The sensitivity and specificity of the BRCAPRO model was determined and compared to the Couch and Myriad mutation carrier probability models.; The sensitivity of the BRCAPRO model was 78.0% and specificity was 68.2%. This was superior to the Couch (sensitivity 56.3%; specificity 72.3%) and Myriad (sensitivity 64.1%; specificity 65.1%) models. The joint sensitivity and specificity for this sample was 88.0% and 55.0%, respectively.; The BRCAPRO model shows promise as an assessment tool for predicting the risk of carrying a BRCA1/BRCA2 mutation. Since not all genetic mutations predisposing one to breast/ovarian cancer have been accounted for, this model is not 100% accurate in detecting carrier status, and should be used in conjunction with traditional genetic counseling methods. Statistical assessment models provide a valuable resource for nurses who participate in genetic risk counseling. Such tools can help to improve the quality of preventive care provided to individuals at increased risk for developing breast/ovarian cancer due to a genetic predisposition.