Abstract 5206: Recent incidence trends of lymphoid malignancies in Hong Kong, 2001-2010
Authors: Bassig Bryan A. , Au Wing-Yan , Mang Oscar , Ngan Roger , Morton Lindsay M. , K.M. Ip Dennis , Hu Wei , Zheng Tongzhang , Seow Wei Jie , Xu Jun , Rothman Nathaniel , Lan Qing 
Published: July 2016

Abstract
Incidence trends of lymphoid malignancies in the United States (U.S.) have been well-characterized based on analyses of data from the Surveillance, Epidemiology, and End Results Program. These analyses showed marked increases in incidence rates of non-Hodgkin lymphoma (NHL) in the early to mid-1990s, with some evidence that rates have begun to level off in the recent decade. In contrast, there are limited published data on trends in rates of lymphoid malignancies in the Chinese population, particularly for subtypes. Such analyses may provide insight into geographic differences in the descriptive epidemiological patterns of these neoplasms as well as etiological hypotheses. To explore recent trends in incidence rates in HK, yearly age-adjusted incidence rates and annual percent changes (APCs) were calculated using available data over the period 2001-2010 for overall lymphoid malignancies, overall B-cell neoplasms not including Hodgkin lymphoma (HL), overall NK or T-cell tumors, HL, plasma cell neoplasms (PCN), and specific NHL B-cell subtypes that were most common in the HK population over this time period, including diffuse large B-cell lymphoma (DLBCL), marginal zone lymphoma (MZL), and follicular lymphoma (FL). The incidence of overall lymphoid malignancies showed a steady increase in HK over the period 2001-2010 with an APC of +1.4% (95% CI = + 0.4%, + 2.3%). A steady rate of increase was further observed over the ten year period for overall B-cell neoplasms not including HL (APC = +1.6%, 95% CI = + 0.4%, + 2.9%), whereas the incidence of overall T- and NK/T cell neoplasms showed no significant fluctuation over the ten year period (APC = -1.1%, 95% CI = -3.5%, +1.5%). For the most common subtypes diagnosed in HK during the study period, an increasing trend of HL was observed over the years 2004-2010 only (APC = + 10.5%, 95% CI = + 4.9%, + 16.4%) based on the best-fitting model that included one joinpoint, and stable but non-significant rates of increase for DLBCL (APC = + 1.5%, 95% CI = - 0.7%, + 3.6%), PCN (APC = + 1.2%, 95% CI = -0.2%, + 2.6%), and FL (APC = + 2.7%, 95% CI -0.5%, 6.0%) were also observed, all over the period 2001-2010. Conversely, incidence rates of MZL showed no significant fluctuation over the study period (APC = -1.0%, 95% CI = -2.9%, +0.8%). The overall trends observed during even this relatively short time-period suggest that the rate of several lymphoid malignancies in HK may be beginning to shift in the direction of rates that were observed among individuals living in the U.S. Additional analyses of population-based registry data from other regions in East Asia, especially over longer time-periods, are needed to replicate and extend these findings. Further, our results support the need for etiological studies of lymphoid malignancies in this population, particularly as it relates to environmental, occupational and lifestyle risk factors that might influence disease rates and the genetic risk factors that potentially interact with them.
Citation Format: Bryan A. Bassig, Wing-Yan Au, Oscar Mang, Roger Ngan, Lindsay M. Morton, Dennis K.M. Ip, Wei Hu, Tongzhang Zheng, Wei Jie Seow, Jun Xu, Nathaniel Rothman, Qing Lan. Recent incidence trends of lymphoid malignancies in Hong Kong, 2001-2010. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5206.