HUMAN IMMUNODEFICIENCY VIRUS AND CANCER IN CHILDREN IN SOUTH AFRICA

Background. Infection with human immunodeficiency virus-1 (HIV) increases the incidence of certain cancers in adults. Much less is known about the impact of infection on the risk of cancer in children.

Aim. This study aimed to: 1) investigate the association between HIV infection and various cancers in children; and 2) compare the outcomes after cancer therapy between children with and without HIV.

Patients and methods. In the first study, the occurrence rates of various malignancies were analyzed on a group of 882 children with cancer, where 38 were HIV positive. The association between each cancer type and HIV was analyzed using all other cancers as controls – excluding those already known to be HIV-associated: Kaposi sarcoma (KS) and lymphomas. The association between HIV and outcome after treatment with standard cytostatic protocols and anti-retroviral medication was evaluated in a second study, on a group of 669 children with cancer out of which 99 were living with HIV. The data were processed with Student’s t-test and chi-square test in order to discern the statistical significance of the differences recorded. Kaplan-Meyer survival curves were constructed and compared by means of log rank (Mantel-Cox) tests.

Results. In the first study, HIV infection was positively associated with KS - all 10 cases were HIV infected, p<0.001- and Burkitt lymphoma (BL) (OR=46.2, 95% CI 16.4–130.3, based on 13/33 infected cases). In the second study, the Kaplan-Meyer survival curves do not differ significantly by HIV serostatus. However, the proportion of children alive disease-free at the end of follow-up, to the total of children in the respective category, is significantly smaller in the HIV positive subjects: 32.1% vs. 47.7% (chi-squared, 1 degree of freedom, two-tailed p=0.01). Additionally, the proportion of children who died from toxicity (including infection due to marked leucopoenia), to the total in their respective group, is significantly larger in the HIV positive subjects: 11.9% vs. 0.2% (chi-squared, 1 degree of freedom, two-tailed p<0.0001).

Conclusions. HIV is associated with KS and BL among children with cancer in South Africa. The proportion of children disease-free at end of follow-up is significantly lower in children infected with HIV while the proportion of deaths due to toxicity is significantly higher.