Prophylactic mastectomy or screening in women suspected to have the BRCA 1/2 mutation: a prospective pilot study of women's treatment choices and medical and decision-analytic recommendations

Women with a suspected BRCA1/2-mutation may choose between two management options: breast cancer screening or prophylactic mastectomy (PM). Objectives. To compare women's treatment choices, medical and decision analytic recommendations, and to explore variables related to the women's treatment choices. Methods. After provision of information, individual Time tradeoff values for the health outcome 'living after PM' were assessed and incorporated into a decision analytic model, which compared the management options PM and screening with respect to their effect on quality-adjusted life expectancy. Results. Of the 54 women with a suspected BRCA1/2-mutation, 51 women completed the shared decision making procedure. Quality-adjusted life expectancy after PM management was longer for 67% of proven carriers and for 58% of women awaiting the DNA-test result. Twelve proven carriers made a definitive treatment choice; it was the management option PM in eight (67%) and screening in four cases (33%). All carriers treatment choices agreed with the normative decision analytic recommendation. Four carriers (33%) disagreed with the medical recommendations. Of the 36 women awaiting the DNA-test result, 32 made a hypothetical treatment choice. The agreement between these hypothetical treatment choices and the decision analytic recommendation was good (78%). Combining data from all 48 women, being married (OR = 14.00, p = 0.006), having children (OR = 4.71, p = 0.02), a low Desire to Participate (OR = 0.14, p = 0.004), high Decisional stress (OR = 5.22, p = 0.01), a lower estimate of the 'probability of cure for screen-detected breast cancer' (OR = 0.13, p = 0.004), and higher Time tradeoff values for PM (OR = 182, p < 0.0001) made a choice for PM more likely. Conclusions. There was complete agreement between the decision analytic recommendation and the carriers' treatment choices. This suggests that women act in accordance with normative decision theory. The disagreement between the carriers' treatment choices and the medical recommendations suggests that women's choices and physicians recommendations were guided by different arguments. The strong association between the Time tradeoff-value and the treatment choice suggests that the Time tradeoff test is a valid method to assess preferences. Key words: breast cancer; prophylactic mastectomy; screening; preference assessment; shared decision making, utilities