A Clinical Study of Cases in which BRCA1/2 Genetic Tests were Performed after Insurance Coverage as Additional Indication and Future Problems

Abstract

Since April 2020, BRCA1 and BRCA2 genetic tests have additionally covered by insurance for diagnosing hereditary breast and ovarian cancers (HBOC). This study was made to clarify the appropriateness of suggestive findings on which we rely to select a candidate for the testing. Subjects were all breast cancer patients undergone BRCA1/2 genetic tests to diagnose HBOC. Of these patients, we calculated the number of the tests by every inclusion criterion which is described in the guidebook for the HBOC treatment, and the carrying rates of inherited pathogenic variant (carrying rate) were also calculated. As a result, the number of tests performed for 10 years before the insurance coverage amounted to 600 cases, whilst in 2020 when the insurance coverage was approved, the number greatly increased to 126 cases for one year. The carrying rate in cases applicable to either of inclusion criteria was 13%. The carrying rates by inclusion criterion were 19.3% in triple-negative breast cancer patients at or before age 60 years ; 18.5% in those with more than two primary breast cancers ; 16.3% in those at or before age 45 years ; and 15.4% in those who had family history of breast or ovarian cancer within three-degree relatives, In patients who had three inclusion criteria, the carrying rate was as high as 70%. In conclusion, the carrying rate becomes higher when the candidate is applicable to more inclusion criteria, where information of the test result should be offered. With an increase in numbers of tests as well as carriers who inherit pathogenic variant, it would increasingly pose issues of performing risk-reducing mastectomy for the contralateral breast or following-up of pre-symptomatic pathogenic variant carriers.