The impact of public insurance on RRSO for HBOC in Japan: a nationwide data study

In Japan, risk management based on genetic disposition, such as risk-reducing surgery for hereditary breast and ovarian cancer (HBOC), is covered by public insurance only for some cancer patients. However, non-cancer clients are forced to pay a high co-payment. In this study, we examined the impact of risk-reducing salpingo-oophorectomy (RRSO), before and after the April 2020 public insurance coverage, using nationwide data from the Japanese Organization of Hereditary Breast and Ovarian Cancer. The period from March 2006 to March 2020 was defined as before insurance coverage (Pre), and the period from April 2020 to August 2021 was defined as after insurance coverage (Post). In addition, the period from April 2018 to March 2020 was designated as special (short-Pre) to coincide with the post-insurance coverage period. Of the 383 breast cancer patients who underwent genetic testing at Short-Pre, 42 (11.0%) underwent RRSO during that period. Of the 623 breast cancer patients who underwent genetic testing at Post, 142 (22.8%) underwent RRSO during that period. Significantly, this comparison shows an increase in RRSO rates in Post. Separating BRCA1 and BRCA2 also significantly increased RRSO in Post. This nationwide survey suggests that if RRSO is covered by insurance in Japan, the implementation rate will increase. As the number of cases increases in the future, the impact of insurance coverage will become clearer. If the insurance coverage for RRSO in Japan is determined to be useful, this information can be used to expand coverage for those who have not yet developed the disease.