Abstract P1-15-02: Low incidence of hepatitis B reactivation after chemotherapy in Japanese breast cancer patients with resolved HBV

Abstract Background: Recently, chemotherapy-induced reactivation of hepatitis B virus (HBV) has been reported not only in patients with HBV surface antigen positive (HBsAg+) but also in patients with resolved HBV (HBsAg-, anti-HBV-core antibody positive (anti-HBc+). The incidnce of HBV reactivation after adjuvant/neo-adjuvant chemotherapy for breast cancer in patients with resolved HBV infection remains unclear. In this study, we surveyed the incidence of HBV reactivation in Japanese breast cancer patients who received adjuvant/neo-adjuvant chemotherapy. Methods: A total of 3042 breast cancer patients who received neoadjuvant and/or adjuvant chemotherapy from June 2008 to December 2016 were included in this study. HBsAg, anti-HBc and anti-HBV-surface antibody (anti-HBs) were tested before chemotherapy. Serum HBV-DNA levels were subsequently measured and monitored for one year after the completion of adjuvant/neo-adjuvant chemotherapy if the patient exhibited a resolved HBV infection. Results: Of the 3042 patients (pts), 32 (1.05%)cases were positive for HBsAg and 2992 pts were negative for HBsAg. 301 pts (9.9 %) were revealed resolved HBV infection; 221 pts were with anti-HBc+ and anti-HBs+, 40 pts were with anti-HBc+ and anti-HBs-, and 130 pts were with anti-HBc- and anti-HBs+. Of the 130 pts with anti-HBc- and anti-HBs+, 77 pts were previously vaccinated for hepatitis B. The antibody-positive rate by age group was 2.7% (1/37) for patients in their 20s, 4.1% (14/344) for those in their 30s, 6.5% (67/1037) for those in their 40s, 9.4% (77/817) for those in their 50s, 16.6% (109/655) for those in their 60s, 20% (30/150) for those in their 70s, and 0% (0/2) for those in their 80s. Among the 301 pts with resolved HBV infection, 71 pts were monitored for one year after the completion of their chemotherapy. The median monitoring period was 579 days (386-3458). In our monitoring period, only one patient (1.4%) was diagnosed with HBV reactivation based on a slightly elevated HBV-DNA level at 1-year-test. No death or hepatitis due to HBV reactivation occurred during the monitoring period. Conclusions: The prevalence of resolved HBV infection in Japan showed an increasing trend with age. Adjuvant/neoadjuvant chemotherapy for breast cancer patients with resolved HBV infection has a risk of HBV reactivation. Our study suggested the risk of reactivation was low and the risk of a flare of HBV disease could be controlled with screening and carefully monitoring. Citation Format: Takayo Fukuda, Masaya Hattori, Yukinori Ozaki, Lina Inagaki, Mari Hosonaga, Ippei Fukada, Kokoro Kobayashi, Fumikata Hara, Takayuki Kobayashi, Sachiyo Yoshio, Takayuki Ueno, Toshimi Takano, Shinji Ohno. Low incidence of hepatitis B reactivation after chemotherapy in Japanese breast cancer patients with resolved HBV [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-15-02.