Patients Applying Chemotherapy and Immunosuppressive Therapy For patients receiving chemotherapy and immunosuppressive therapy for other diseases, HBsAg should be routinely screened; if positive, lamivudine or other nucleoside (acid) analogs should be initiated 1 week prior to treatment, even if HBV DNA is negative and ALT is normal. In HBsAg-negative, anti-HBc-positive patients, HBV DNA and HBsAg should be monitored closely when long-term or high-dose immunosuppressive or cytotoxic drugs (especially monoclonal antibodies against B or T lymphocytes) are given, and antiviral therapy should be added promptly if positive transitions occur. After the cessation of chemotherapy and immunosuppressive therapy, the timing of discontinuation should be determined according to the patient’s condition (II-1, II-3): (1) For patients with baseline HBV DNA <2,000 IU/mL, treatment should be continued for 6 months after completion of chemotherapy or immunosuppressive therapy (III); (2) For patients with high baseline HBV DNA levels (>2,000 IU/mL), treatment should be continued until they are immunocompetent. treated to the same discontinuation criteria as immunocompetent chronic hepatitis B patients (III). (3) For patients with an expected duration of therapy of ≤12 months, lamivudine (I) or telbivudine (III) may be used. (4) For patients with longer expected duration of therapy, entecavir or adefovir (III) should be preferred. (5) Nucleoside (acid) analogs can cause relapse or even worsening of the disease after discontinuation, which should be highly valued. (6) Interferon has myelosuppressive effect and should be avoided.