Hepatitis B blood tests before anyone starts systemic cancer treatment, with antiviral tablets for those who need them

The recommendation. The 2020 ASCO provisional clinical opinion states that "all patients anticipating systemic anticancer therapy should be tested for HBV by 3 tests" (hepatitis B surface antigen, core antibody and surface antibody), "but anticancer therapy should not be delayed". People with chronic infection receiving any systemic anticancer therapy should receive antiviral prophylaxis during and for at least 12 months after treatment; people with past infection receiving high-risk treatment such as anti-CD20 antibodies or stem cell transplantation should receive prophylaxis or, where follow-up can be relied on, careful monitoring.

Why it works. A 2008 systematic review of 14 studies (two randomised) in surface-antigen-positive patients receiving chemotherapy found relative risks for reactivation and hepatitis between 0.00 and 0.21 with preventive lamivudine; hepatic failure occurred in none of 108 patients given it against 21 of 162 controls, and deaths attributed to hepatitis B in 4 of 208 against 27 of 394. A randomised trial in 121 surface-antigen-positive patients with diffuse large B-cell lymphoma receiving R-CHOP then showed entecavir outperformed lamivudine: hepatitis 0 against 13.3 per cent, reactivation 6.6 against 30 per cent, chemotherapy disrupted 1.6 against 18.3 per cent.

The measured gap. A 2024 meta-analysis of 29 studies found a pooled screening rate before chemotherapy of 57 per cent, rising from 37 per cent in 2006 to 2010 to 69 per cent in 2016 to 2020. Rates were 89 per cent in high-prevalence countries and 49 per cent in low-prevalence ones, 65 per cent in blood cancers against 37 per cent in solid tumours, and 68 per cent with rituximab-containing regimens against 45 per cent without.