Hepatitis B virus（HBV）in a latent or stationary state in breast cancer patients may be reactivated when receiving cytotoxic chemotherapy;the patients can even develop liver injury. Clinical manifestations include asymptomatic self-limiting hepatitis or fulminant hepatic failure leading to interruption of chemotherapy or death. According to the researches

in HBsAg positive breast cancer patients with HBV reactivation

HBV reactivation related hepatitis accounts for 18.4% to 23.5%;HBV reactivation associated interruption of chemotherapy accounts for 12.7% to 33.6%. The pathogenesis of HBV reactivation is generally considered by immune imbalance between HBV and host induced by chemotherapy drug. The associated risk factors include HBV etiology state

HBV DNA loads and chemotherapy regimens

etc. HBV infection should be routinely screened before chemotherapy to reduce the occurrence of breast cancer chemotherapy related HBV reactivation and related complications. HBsAg positive patients should prophylacticly use antiviral drugs. HBsAg negative

and HBcAb positive patients should be closely followed up to early detect HBV reactivation and start the antiviral treatment.