Effects of nucleoside analogue prescription for hepatitis B on the incidence of liver cancer in Hong Kong: a territory-wide ecological study.

Background The temporal relationship between nucleoside analogue therapy for chronic hepatitis B (CHB) and liver cancer development has not been evaluated at a population level. Aim To investigate the impact of nucleoside analogue prescription on liver cancer incidence in a CHB-prevalent region. Methods We obtained territory-wide nucleoside analogue prescription data from 1999, when nucleoside analogue was first available in Hong Kong, to 2012 and the population-based liver cancer incidence data from 1990 to 2012. We compared the liver cancer incidences from 1990 to 1998 and 1999 to 2012 with adjustment for local hepatitis B surface antigen seroprevalence. Results Nucleoside analogue prescription patient headcount increased from 2006 per year in 1999 to 26 411 in 2012. Prescription volume in 2012 was highest among 55-64 years (30.3%), higher than 65-74 years (13.0%) and 75 years (5.8%). Age-standardised liver cancer incidence 1999-2012 decreased by 1.88%/year (95% CI 3.34% to 0.42%/year). NA therapy was associated with decline in age-adjusted liver cancer incidence (2.7 per 100 000 persons, P < 0.001, 95% CI 1.4-4.0 per 100 000 persons). Fifty-five to sixty-four years age group had the most significant decline (men: 24.0 per 100 000 persons, P = 0.001, 95% CI 11.4-36.6 per 100 000 persons; women: 8.5 per 100 000 persons, P = 0.009, 95% CI 2.3-14.6 per 100 000 persons). No significant association was noted in age groups 65-74 years and 75 years (both P > 0.05). Conclusions Nucleoside analogue prescription was associated with a reduction of overall liver cancer incidence in a CHB-prevalent region. The lack of association among individuals of 65 years was consistent with the low nucleoside analogue prescription volume in elderly patients, mitigating the impact of CHB treatment on liver cancer.