The epidemic of non-Hodgkin lymphoma in the United States: disentangling the effect of HIV, 1992-2009.

BACKGROUND For decades, non-Hodgkin lymphoma (NHL) incidence has been increasing worldwide. NHL risk is strongly increased among HIV-infected people. Our understanding of trends in NHL incidence has been hampered by difficulties in separating HIV-infected NHL cases from general population rates. METHODS NHL incidence data during 1992-2009 were derived from 10 U.S. SEER cancer registries with information on HIV status at NHL diagnosis. The CDC estimated the number of people living with HIV in the registry areas. The proportion of NHL cases with HIV and NHL rates in the total and the HIV-uninfected populations were estimated. Time trends were assessed with Joinpoint analyses. RESULTS Of 115,643 NHL cases diagnosed during 1992-2009, 5.9% were HIV-infected. The proportions of NHL cases with HIV were highest for diffuse large B-cell (DLBCL; 7.8%), Burkitt (26.9%), and peripheral T-cell lymphomas (3.2%) with low proportions (≤1.1%) in the other subtypes. NHL rates in the total population increased 0.3% per year during 1992-2009. However, rates of NHL in HIV-uninfected people increased 1.4% per year during 1992-2003, before becoming stable through 2009. Similar trends were observed for DLBCLs and follicular lymphoma in HIV-uninfected people; rates increased 2.7% per year until 2003 and 1.7% per year until 2005, respectively, before stabilizing. CONCLUSIONS NHL incidence rates in the United States have plateaued over the last 5-10 years, independent of HIV infection. IMPACT Although the causes of the long-term increase in NHL incidence rates in the United States remain unknown, general population rates of NHL have stabilized since the early 2000s, independent of HIV.