Promoters of BRCA testing under insurance coverage for non-metastatic breast cancer patients in Japan: a retrospective cohort study.

ABSTRACT

BACKGROUND: We investigated the barriers to and promoters of taking BRCA testing, after the start of national healthcare insurance coverage for non-metastatic breast cancer patients in Japan. PATIENTS AND METHODS: This was a multi-center, retrospective, cohort study. We included stage 0 to III breast cancer patients who were diagnosed and met the criteria for insurance coverage of BRCA testing between April 2020 and December 2021. We examined the association between BRCA testing and possible exposures breast cancer diagnosis at 45 years or younger, triple-negative breast cancer (TNBC) diagnosis at the age of 60 or younger, two or more primary breast cancers, family history of breast cancer or ovarian cancer in the third degree of relatives, male breast cancer, medical expense limits, and parity. We used logistic regression analysis. RESULTS: We included 222 patients and 123 (55.4%) of them underwent the test. In univariate analysis, a family history of ovarian cancer (odds ratio (OR) 10.59; 95% CI 1.35-82.96, p = 0.025), diagnosis of breast cancer at the age of 45 or younger (OR 2.78; 95% CI 1.52-5.14, p = 0.0009), and diagnosis of TNBC at the age of 60 or younger (OR 3.95; 95% CI 1.55-10.07, p = 0.004) were associated with taking the test. After multivariate logistic regression analysis, a family history of ovarian cancer (adjusted OR 12.80; 95% CI 1.51-108.80, p = 0.0195), diagnosis of breast cancer at the age of 45 or younger (adjusted OR 4.43; 95% CI 1.98-9.90, p = 0.0003), and TNBC at the age of 60 or younger (adjusted OR 5.28; 95% CI 1.90-14.66, p = 0.0014) were consistently associated. CONCLUSION: For non-metastatic breast cancer patients whose BRCA testing is covered by insurance, costs would no longer be a definite barrier. Physicians should keep in mind that a family history of ovarian cancer, breast cancer diagnosis at 45 years of age or younger and TNBC diagnosis at 60 years of age or younger are strong promoters.