The challenge of AIDS-related malignancies in sub-Saharan Africa

Abstract

Background: With the lengthening of life expectancy among HIV-positive subjects related to the use of highly active antiretroviral treatments, an increased risk of cancer has been described in industrialized countries. The question is to determine what occurs now and will happen in the future in the low income countries and particularly in sub-Saharan Africa where more than two-thirds of all HIV-positive people live in the world. The objective of our paper is to review the link between HIV and cancer in sub-Saharan Africa, putting it in perspective with what is already known in Western countries.

Methods and findings: Studies for this review were identified from several bibliographical databases including Pubmed, Scopus, Cochrane, Pascal, Web of Science and using keywords "HIV, neoplasia, epidemiology and Africa" and related MesH terms. A clear association was found between HIV infection and AIDS-classifying cancers. In case-referent studies, odds ratios (OR) were ranging from 21.9 (95% Confidence Interval (CI) 12.5-38.6) to 47.1 (31.9-69.8) for Kaposi sarcoma and from 5.0 (2.7-9.5) to 12.6 (2.2-54.4) for non Hodgkin lymphoma. The association was less strong for invasive cervical cancer with ORs ranging from 1.1 (0.7-1.2) to 1.6 (1.1-2.3), whereas ORs for squamous intraepithelial lesions were higher, from 4.4 (2.3-8.4) to 17.0 (2.2-134.1). For non AIDS-classifying cancers, squamous cell conjunctival carcinoma of the eye was associated with HIV in many case-referent studies with ORs from 2.6 (1.4-4.9) to 13.0 (4.5-39.4). A record-linkage study conducted in Uganda showed an association between Hodgkin lymphoma and HIV infection with a standardized incidence ratio of 5.7 (1.2-17) although OR in case-referent studies ranged from 1.4 (0.7-2.8) to 1.6 (1.0-2.7). Other cancer sites found positively associated with HIV include lung, liver, anus, penis, vulva, kidney, thyroid and uterus and a decreased risk of female breast cancer. These results so far based on a relatively small number of studies warrant further epidemiological investigations, taking into account other known risk factors for these tumors.

Conclusion: Studies conducted in sub-Saharan Africa show that HIV infection is not only strongly associated with AIDS-classifying cancers but also provided some evidence of association for other neoplasia. African countries need now to implement well designed population-based studies in order to better describe the spectrum of AIDS-associated malignancies and the most effective strategies for their prevention, screening and treatment.

Figure 1. Odds Ratio (OR) and corresponding 95% confidence interval (95% CI) for the association between Kaposi sarcoma and HIV in sub-Saharan Africa.

Figure 2. Odds Ratio (OR) and corresponding 95% confidence interval (95% CI) for the association between Non Hodgkin lymphoma and HIV in sub-Saharan Africa.

Figure 3. Odds Ratio (OR) and corresponding 95% confidence interval (95% CI) for the association between cervical abnormalities, invasive cervical cancer and HIV in sub-Saharan Africa.

* squamous intraepithelial lesions † low-grade SIL ‡ high-grade SIL.