Cancer Risk Estimates for Study of Multiple-Gene Testing After Diagnosis of Breast Cancer

To the Editor Kurian et al document the proportion of women among SEER breast cancer patients who had undergone genetic testing and had a preventive mastectomy of the contralateral breast, according to risk profile. Of those with a bona fide BRCA1/2 mutation, 79% had a bilateral mastectomy. Of those with a pathogenic variant in another gene, 38% had a bilateral mastectomy, and of those with a variant of unknown significance, 30% had a bilateral mastectomy. Of those with no mutation, 35% had a bilateral mastectomy. The data on BRCA1 and BRCA2 are useful, and genetic testing in this regard is warranted. However, on the basis of this analysis, Kurian et al conclude that the testing of genes other than BRCA1 and BRCA2 has clinical value by increasing the number of women with a mutation that places them at high risk. In my opinion, the article supports the opposite view. Among patients with a pathogenic variant in another gene, a variant of unknown significance, or no mutation, there appears to be no correlation between the objective inherent cancer risk and the action taken by patients. The operation was not recommended by the surgeon (except in rare cases), and I suspect the primary motives behind the surgery were fear and anxiety. It is unsettling that the rates of bilateral mastectomy are high in all categories; the fact that decisions regarding choice of surgery are made not with respect to the results of a formal risk assessment but as a consequence of the emotional state of the patient raises serious doubts about the basis of personalized medicine. This study confirms my research group's earlier work on preventive mastectomy. To look at the rationale for mastectomy more closely, it would be helpful to generate specific risk estimates for cancer and contralateral breast cancer for the entire study population and to determine whether any correlation exists between cancer risk and mastectomy that might be missed at the group level.

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