The impact of an interventional counselling procedure in families with a BRCA1/2 gene mutation: efficacy and safety.

BACKGROUND

Predictive genetic testing has high impact on cancer prevention for BRCA carriers and passing this information in BRCA families is important. Mostly, this is proband-mediated but this path is defective and denies relatives lifesaving information.

OBJECTIVE

To assess the efficacy/safety of an intervention, in which relatives are actively informed.

DESIGN

Sequential prospective study in new BRCA families. The proband informed relatives about predictive testing (phase I). After 6 months, a letter was sent to adult relatives who had not been reached (phase II). Then a phone call was made to obtain a final notion of their wishes. All subjects received psychometric testing (State-Trait Anxiety Inventory, STAI), an interview and routine counselling.

RESULTS

Twenty families were included. Twenty-four of the relatives could not be reached, 59 were 'decliners', 47 participated by the proband and 42 by the letter. Predictive testing was performed in 98% of the participants of which 30 were mutation carriers. The intervention is psychologically safe: the 95% CI for the estimated mean difference in STAI DY1 between phase II/I subjects (mean difference -1.07, 95% CI -4.4 to 2.35, p = 0.53) shows that the mean STAI DY1 score (measured at first consult) for phase II is no more than 2.35 units higher than for phase I, which is not relevant.

CONCLUSIONS

A protocol directly informing relatives nearly doubles the number of relatives tested and is psychologically safe. This should lead to a change in counselling guidelines in families with a strong germline predisposition for cancer.