Time trends in cancer incidence in persons living with HIV/AIDS in the antiretroviral therapy era: 1997-2012

Abstract

Objective: Utilizing the Veterans Aging Cohort Study, the largest HIV cohort in North America, we conducted one of the few comprehensive comparisons of cancer incidence time trends in HIV-infected (HIV+) versus uninfected persons during the antiretroviral therapy (ART) era.

Design: Prospective cohort study.

Methods: We followed 44 787 HIV+ and 96 852 demographically matched uninfected persons during 1997-2012. We calculated age-, sex-, and race/ethnicity-standardized incidence rates and incidence rate ratios (IRR, HIV+ versus uninfected) over four calendar periods with incidence rate and IRR period trend P values for cancer groupings and specific cancer types.

Results: We observed 3714 incident cancer diagnoses in HIV+ and 5760 in uninfected persons. The HIV+ all-cancer crude incidence rate increased between 1997-2000 and 2009-2012 (P trend = 0.0019). However, after standardization, we observed highly significant HIV+ incidence rate declines for all cancer (25% decline; P trend <0.0001), AIDS-defining cancers (55% decline; P trend <0.0001), nonAIDS-defining cancers (NADC; 15% decline; P trend = 0.0003), and nonvirus-related NADC (20% decline; P trend <0.0001); significant IRR declines for all cancer (from 2.0 to 1.6; P trend <0.0001), AIDS-defining cancers (from 19 to 5.5; P trend <0.0001), and nonvirus-related NADC (from 1.4 to 1.2; P trend = 0.049); and borderline significant IRR declines for NADC (from 1.6 to 1.4; P trend = 0.078) and virus-related NADC (from 4.9 to 3.5; P trend = 0.071).

Conclusion: Improved HIV care resulting in improved immune function most likely contributed to the HIV+ incidence rate and the IRR declines. Further promotion of early and sustained ART, improved ART regimens, reduction of traditional cancer risk factor (e.g. smoking) prevalence, and evidence-based screening could contribute to future cancer incidence declines among HIV+ persons.

Figure 1. All cancer crude and standardized IRs by HIV status and calendar period and p-values for IR period trend

HIV+, HIV-infected; IR, incidence rate.

Figure 2. Cancer group IRs (per 100,000 person-years) by HIV status and calendar period, IRRs with 95% confidence intervals by period, and p-values for IRR period trend

ADC, AIDS-defining cancer; HIV+, HIV-infected; IR, standardized incidence rate; IRR, standardized incidence rate ratio; NADC, non-AIDS-defining cancer; Non-virus-NADC, non-virus-related non-AIDS-defining cancer; Virus-NADC, virus-related non-AIDS-defining cancer. Note that Y-axis scale varies by cancer group.

Figure 3. Proportion of cancer cases among HIV+ patients by cancer group in each calendar period

ADC, AIDS-defining cancer; HIV+, HIV-infected; Non-virus-NADC, non-virus-related non-AIDS-defining cancer; Virus-NADC, virus-related non-AIDS-defining cancer. To calculate cancer group proportions, we included all incident cancer cases, not just the first diagnosis for each subject. For example, a subject diagnosed with both Kaposi sarcoma and colorectal cancer during the observation period contributed one ADC case and one non-virus-NADC case, and a subject diagnosed with both hepatocellular carcinoma and Hodgkin lymphoma contributed two virus-NADC cases.