People with HIV/AIDS (PWHA) have higher risk of some cancers compared to the general population, with an approximately 2-fold increase for all non-AIDS-defining cancers (NADC). The widespread use of highly active antiretroviral therapy (HAART) has improved life expectancy of PWHA, exposing them to both aging and the prolonged exposure to cancer risk factors. A linkage study was therefore conducted to evaluate the impact of aging on the burden of cancer in this population.
Materials and methods
We performed an anonymous record linkage between Italian AIDS (21,951 cases) and Cancer Registries (17.3 million people, covering 30% of the general population). Crude incidence rates (IR), IRs directly standardized by sex and age, and age-specific IRs were estimated for NADCs in the pre-HAART (1986-1996) and in the HAART (1997-2004) periods.
Crude IRs of NADCs increased 78% from pre-HAART to HAART period (IRs: 287 and 496 per 100,000, respectively). However, when aging of PWHA was taken into account through standardization, no difference emerged (standardized IRs: 352 and 379 per 100,000, respectively). Concerning specific cancer site/type, standardized IRs revealed an increase of liver (from 6 to 26 per 100,000; IR ratio: 4.6, 95% confidence interval, CI: 1.3-17.0) and lung cancers (from 37 to 65 per 100,000; IR ratio: 1.8, 95% CI: 1.0-3.2). No significant variation across periods emerged for Hodgkin lymphoma (IRs: 83 and 69 per 100,000 in pre- and HAART period; IR ratio: 0.8, 95% CI: 0.5-1.3). IRs of NADCs increased with age from 147 per 100,000 in PWHA aged 25-34 years to 1396 per 100,000 in those aged 55-69 years (Figure 1); however, the rise was smoother than in the general population. As a consequence, the excess of NADCs risk declined with age, peaking in PWHA aged 25-44 years (IRs ratio: 2.7) and disappearing in the oldest age group (IRs ratio: 1.1; 95% CI: 0.8-1.5). (Table 1)
The lack of any change in standardized IRs of NADCs across periods highlights the strong influence of PWHA aging on the observed upward trends of crude IRs. The aging of PWHA in HAART period, together with the age-related increase of cancer incidence, points to cancer as an increasing medical priority for this population in the near future. This calls for the intensification of cancer prevention strategies, notably smoking cessation and screening programs.
This article has been published as part of Infectious Agents and Cancer Volume 5 Supplement 1, 2010: Proceedings of the 12th International Conference on Malignancies in AIDS and Other Acquired Immunodeficiencies (ICMAOI).The full contents of the supplement are available online at http://www.biomedcentral.com/1750-9378/5?issue=S1.