Risk perception in genetic counselling for hereditary breast/ovarian cancer

Abstract

1541 Background: The estimation of the objective risk (OR) to develop a tumour is a crucial element of genetic counselling. The estimation of the subjective risk (SR) is also important because it affects the patients distress level and influences their adhesion to clinical management. This study evaluates the perception levels of the risk to be a mutation carrier and to develop a related-cancer, the association between perceived risk and medical / psychological variables and the adequacy of the perceived risk compared to the objective risk estimated by BRCApro model. Methods: Before collecting family pedigree, the patients were informed about the clinical involvement of BRCA1/BRCA2 genes mutation, and then about their eligibility to genetic testing and objective risk as estimated by BRCApro model. At this time, questionnaires for evaluation of medical-demographic characteristics, Cancer and Genetic Risk Perception (CRP, GRP) and Hospital Anxiety Depression scale were administered. Statistical analysis was performed by Pearson chi-square test, t-test, Cohen's coeff. of agreement and non parametric test. Results: 130 subject were evaluated: women/men=119/11, 32% affected, 68% healthy with at least two cancer affected-relative. Overall, subjects entering into genetic counselling had higher anxiety level (median score >13) than normal population (< 13) and overestimated their genetic (67%) and tumor risk (56%). The SR was found to be correlated to OR as assessed by BRCApro (CRP r=0.254 p=0.006; GRP r=0.322 p<0.000) but the OR is significantly lower than the SR (CRP=39% vs19%, p<0.001; GRP=31% vs 11%, p<0.001). Subjects eligible for genetic testing showed a higher perception of risk when compared to non-eligible (CRP p=0.024; GRP p<0.001) even if this estimate was more in accordance with BRCApro model than in non eligible (CRP p=0.001; GRP p=0.006). The subjects with less cancer-affected relatives significantly overestimated their risk of being mutation carrier (p=0.028). No association was found between other medical-demographic variables. Conclusions: Subjective and objective risk were found to be correlated. However, a high percentage of subjects overestimate their risk. Only the eligible status and the number of cancer affected relatives seem to influence the perceived risk. No significant financial relationships to disclose.