Excess cancers among HIV-infected people in the United States

Abstract

Background: Nearly 900 000 people in the United States are living with diagnosed human immunodeficiency virus (HIV) infection and therefore increased cancer risk. The total number of cancers occurring among HIV-infected people and the excess number above expected background cases are unknown.

Methods: We derived cancer incidence rates for the United States HIV-infected and general populations from Poisson models applied to linked HIV and cancer registry data and from Surveillance, Epidemiology, and End Results program data, respectively. We applied these rates to estimates of people living with diagnosed HIV at mid-year 2010 to estimate total and expected cancer counts, respectively. We subtracted expected from total cancers to estimate excess cancers.

Results: An estimated 7760 (95% confidence interval [CI] = 7330 to 8320) cancers occurred in 2010 among HIV-infected people, of which 3920 cancers (95% CI = 3480 to 4470) or 50% (95% CI = 48 to 54%) were in excess of expected. The most common excess cancers were non-Hodgkin's lymphoma (NHL; n = 1440 excess cancers, occurring in 88% excess), Kaposi's sarcoma (KS, n = 910, 100% excess), anal cancer (n = 740, 97% excess), and lung cancer (n = 440, 52% excess). The proportion of excess cancers that were AIDS defining (ie, KS, NHL, cervical cancer) declined with age and time since AIDS diagnosis (both P < .001). For anal cancer, 83% of excess cases occurred among men who have sex with men, and 71% among those living five or more years since AIDS onset. Among injection drug users, 22% of excess cancers were lung cancer, and 16% were liver cancer.

Conclusions: The excess cancer burden in the US HIV population is substantial, and patterns across groups highlight opportunities for cancer control initiatives targeted to HIV-infected people.

Figure 1.

Estimated excess cancer cases among people living with human immunodeficiency virus (HIV) in the United States in 2010, by age and time since an AIDS diagnosis. Excess cancer cases are displayed by age (A and B) and time since an AIDS diagnosis (C and D) on an absolute scale (A and C) and on a percentage scale (B and D). Totals for individual groups do not match Table 3 exactly, as deficits (ie, negative excesses) for individual cancer sites within each group are set equal to zero for graphical presentation. Estimates of excess cancers, including deficits, simultaneously stratified by cancer type and demographic and HIV-related characteristics, are presented in Supplementary Tables 1–4 (available online). HIV = human immunodeficiency virus; HL = Hodgkin’s lymphoma; KS = Kaposi’s sarcoma; NHL = non-Hodgkin’s lymphoma.

Figure 2.

Estimated excess cancer cases among people living HIV in the United States in 2010, by HIV risk group and race/ethnicity. Excess cancer cases are displayed by HIV risk group (A and B) and race/ethnicity (C and D) on an absolute scale (A and C) and on a percentage scale (B and D). Totals for individual groups do not match Table 3 exactly, as deficits (ie, negative excesses) for individual cancer sites within each group are set equal to zero for graphical presentation. Estimates of excess cancers, including deficits, simultaneously stratified by cancer type and demographic and HIV-related characteristics are presented in Supplementary Tables 1–4 (available online). Individuals who are both men who have sex with men (MSM) and injection drug users are classified as MSM. het. = heterosexuals; HIV = human immunodeficiency virus; IDU = injection drug users; KS = Kaposi’s sarcoma; MSM = men who have sex with men; NH = non-Hispanic; NHL = non-Hodgkin’s lymphoma.