Abstract 1381: Reduction in aflatoxin exposure drives decrease in primary liver cancer in Qidong, China.

Abstract

Abstract Primary liver cancer (PLC) causes nearly 700,000 annual deaths worldwide predominately in Asia and sub-Saharan Africa; >370,000 deaths occur in the People's Republic of China, alone. Two factors synergistically associated with PLC are chronic infection with hepatitis B (HBV) and repetitive ingestion of aflatoxin (AFB)-contaminated foods. Utilizing information collected over several decades by the Qidong Cancer Registry, mortality rates from PLC were compared to timelines for regional implementation of HBV vaccination and levels of AFB exposure. The concentration of the AFB-lysine adduct was quantified by isotope dilution mass spectrometry in randomized, age-matched subsets of archived serum samples collected from 1989-2012. Economic, social and public health changes occurring during this time period were examined including implementation of a universal vaccination program and the adaptation of an open policy of food provisionment which led to rice replacing maize as the major dietary staple in the Qidong region. Although the crude rates of PLC increased from 1972-1990s (50/100,000 to a steady-state rate of 75/100,000), much of the increase can be attributed to a proportionate aging population. Upon stratifying by birth cohort, no significant change in mortality rate from PLC was found for individuals over 40 years of age. However, 60-75% mortality declines in 20-24, 25-29, 30-34 year olds born 1973-177 compared to similar birth cohorts of 1958-1962 were observed. The prevalence of HBV surface antigen positivity was unchanged; moreover, all these birth cohorts were born before the universal HBV vaccination of newborns. Median levels of the aflatoxin biomarker dropped from 19.3 pg/mg albumin in 1989 to non-detectable by 2009. The estimated population attributable risk of AFB-related PLC decreased from 45% in 1989 to 11% in 2012. Significant reductions in PLC mortality occurred prior to the introduction of universal hepatitis vaccination in Qidongese newborns. Agricultural and economic reforms instituted in the 1980s leading to the establishment of rice as a dietary staple was associated with a 40-fold reduction in AFB exposure. Thus, by extrapolation, changes in food-based policies altering exposure to carcinogens in the diet can have a dramatic impact on PLC mortality worldwide. Supported by NIEHS P01 ES 006052, NST China No. 2008ZX10002-015, No. 2012ZX10002-008. Citation Format: Patricia A. Egner, Jian-Guo Chen, Derek Ng, Lisa P. Jacobson, Alvaro Munoz, Jian-Hua Lu, Yuan-Rong Zhu, Geng-Sun Qian, Tao-Yang Chen, Felicia Wu, Jian-Min Wang, John D. Groopman, Thomas W. Kensler. Reduction in aflatoxin exposure drives decrease in primary liver cancer in Qidong, China. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1381. doi:10.1158/1538-7445.AM2013-1381