Residents of Qidong, China, located at the mouth of the Yangtze River, are undergoing a rapid fluctuation in cancer incidence rates at many organ sites, reflecting a dynamic interplay of socio-behavioral, economic and environmental factors. As tracked by their cancer registry, there are extraordinary changes in the China age-standardized incidence rates for the two leading cancer killers in the Qidong region: one going down and the other one up, liver and lung cancer respectively. In endemic areas such as Qidong, liver cancer arises from chronic infection with hepatitis B virus (HBV) and ingestion of aflatoxins. Agricultural and economic reforms in the 1980s promoted a switch from maize to rice as the dietary staple, with concomitant >40-fold decreases in aflatoxin exposure over this period as measured by aflatoxin-albumin adducts in archived serum samples. Universal, subsidized vaccination against HBV was initiated in the early 2000s and likely does not account for the 45% drop in liver cancer incidence over the past quarter century, but augurs well for the future. Age standardized incidence rates for lung cancer, by contrast, have tripled in men over this period, reflecting the high prevalence of smoking (~60%) in adult males and increasing numbers of cigarettes smoked. Women in Qidong, on the other hand rarely smoke. Nonetheless, their rates of lung cancer incidence have doubled over the past decade only, perhaps related to changing patterns of exposures to indoor and outdoor air pollution. Approaches to modulate the impact of these exposures through chemopreventive interventions will be presented. Both primary and secondary prevention strategies appear to offer opportunities for risk reduction in this shifting landscape of exposures to environmental carcinogens.
Citation Format: Thomas W. Kensler, Jian-Guo Chen, Tao-Yang Chen, Patricia Egner, Derek Ng, Alvaro Munoz, John Groopman. Changing landscape of environmental carcinogenesis in Qidong, China: Lessons for prevention. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr PL02-03.