Abstract 5501: The non-Hodgkin lymphoma epidemic in the United States: Recent trends in the absence of HIV-related cases
Authors: Shiels Meredith S. , Engels Eric A. , Clarke Christina , Hall H. Irene , Hartge Patricia , Li Jianmin , Linet Martha S. , Morton Lindsay M. 
Published: August 2012

Abstract
Background: Non-Hodgkin lymphoma (NHL) incidence has been increasing for decades worldwide. NHL risk is strongly increased among people with HIV. NHL rates increased steeply throughout the 1980s in HIV-infected individuals and declined sharply in the mid-1990s with improved HIV therapies. Our understanding of secular trends of HIV-unrelated NHL has been hampered by difficulties in removing the influence of HIV-related NHL cases from general population rates. Methods: We evaluated NHL rates by sex and age during 1992-2008 using data from 10 Surveillance, Epidemiology and End Results (SEER) cancer registries that collected data on HIV status of NHLs from medical records. The proportion of NHLs with HIV and NHL rates with and without HIV-related cases were estimated for NHL subtypes. Time trends were assessed with Joinpoint. Results: Of 107,873 cases of NHL diagnosed during 1992-2008, 6% were HIV-related. The proportion with HIV was greater among men (10%) than women (1%), and among 0-29 (10%) and 30-59 year olds (15%) than ≥60 year olds (0.8%). Eight percent of diffuse large B-cell lymphomas and 27% of Burkitt lymphomas were HIV-related, with low HIV prevalence (&lt;2%) in the other subtypes. Time trends in NHL rates in the overall population were substantially different from those observed after excluding HIV-related cases. During 1992-2008, overall NHL rates increased 0.3% per year, whereas rates excluding HIV-related cases increased 1.3% per year until 2003 and then declined non-significantly through 2008. In men, there was no significant trend in NHL rates overall, but rates excluding HIV-related cases increased 1.9% per year during 1992-1999 and then remained unchanged through 2008. Similar results were observed for women overall and excluding HIV-related cases (1992-2003: 1.5% increase per year, 2003-2008: no significant change). In 0-29 year olds, there was no significant trend in NHL incidence overall, but, after excluding HIV-related cases, rates in the general population increased 1.2% per year. In 30-59 year olds, overall NHL rates increased 6.3% per year during 1992-1994 followed by a non-significant decline through 2008, whereas rates after excluding HIV-related cases increased 0.8% per year until 2002 before declining 1.5% per year thereafter. Exclusion of HIV-related cases had no impact on rates in ≥60 year olds (1992-2004: 1.6% increase; 2004-2008: no significant change). Conclusions: A substantial number of NHL cases were HIV-related, particularly in the early 1990s. Monitoring of overall NHL rates in SEER masked disparate trends in HIV-related and HIV-unrelated NHL rates. After exclusion of HIV-related NHL, HIV-unrelated NHL rates increased more steeply than NHL rates overall during 1992-2003, followed by a non-significant decline in HIV-unrelated rates through 2008. Continued monitoring of HIV-unrelated NHL is critical to ascertain if the long-standing epidemic of NHL has ended.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5501. doi:1538-7445.AM2012-5501