South African youth with HIV and low CD4 counts at higher risk of cancer

People living with HIV between the ages of 15 and 24 who have a low CD4 count have a higher risk of cancer, especially cancers caused by viral infections that target a weak immune system. 

Researchers recommend screening HIV positive youth for cervical cancer, as well as vaccinating youth against HPV (human papillomavirus, which causes cervical cancer). They also encourage more HIV testing and starting regular antiretroviral therapy as soon as possible to try and prevent cancers caused by infections due to a weakened immune system.

HIV infection among the youth is a big health problem in South Africa. Scientists already know that people living with HIV are at a higher risk of cancer, but they haven't looked much into cancer cases in youth specifically

In this study, the researchers wanted to see how many HIV positive youths also had cancer, and what the risk factors might be for different kinds of cancers.

They looked through specific South African patient records of people aged between 15 and 24, between the years 2004 and 2014. They looked for links between different cancers and, for example, the sex, age, and CD4 cell count of the patients.

The researchers report that Kaposi sarcoma was the most common cancer, followed by non-Hodgkin’s lymphoma, Hodgkin’s lymphoma, cervical cancer, and leukaemia. 

They think Kaposi sarcoma, which is caused by a viral infection, was most common because fewer youths are on HIV treatment. People with HIV who are not on treatment may have weaker immune systems unable to fight a viral infection. 

The researchers also found that the risk of developing cancer was higher in people aged 20 to 24 than in people aged 15 to 19. For example, they found that more individuals aged between 20-24 developed non-cervical carcinoma, cervical cancer and Kaposi sarcoma. 

Their results also showed that males had higher incidence rates of any cancer because only 11% of males did not have cancer. 

The researchers report that except for leukaemia, a lower CD4 cell count was linked to higher rates of all cancers, especially Kaposi sarcoma.  They observed slightly higher CD4 cell counts in those aged 15-19 compared to those aged 20-24.

This was the first large study to assess cancer risk among HIV positive youth across South Africa. 

But despite having looked at nearly 800 000 patient records, the researchers said the numbers for specific cancer types were small. 

They also said that they could not get some of the patient information they needed.

They cautioned other researchers may have used different ways to define occurrences of cancer, so these results might not compare easily to others.

Abstract

We studied the incidence of and risk factors for various types of cancers in adolescents and young adults living with HIV (AYALWH) in South Africa between 2004 and 2014. We included individuals aged 15 to 24 years from the South African HIV Cancer Match study, a large cohort resulting from a linkage between HIV-related laboratory measurements from the National Health Laboratory Services and records from the National Cancer Registry. We computed incidence rates for the most common cancers. We assessed associations between these cancers and sex, age, calendar year, and CD4 cell count using Cox models and adjusted hazard ratios (aHR). We included 782,454 AYALWH (89% female). Of those, 867 developed incident cancer including 429 who developed Kaposi sarcoma, 107 non-Hodgkin lymphoma, 48 Hodgkin lymphoma, 45 cervical cancer, and 32 leukaemia. Kaposi sarcoma was more common in the 20-24 year age group than the 15-19 year age group (aHR 1.39, 95% CI 1.03-1.86). Male sex was associated with higher rates of Kaposi sarcoma (aHR 2.06, 95% CI 1.61-2.63), non-Hodgkin lymphoma (aHR 3.17, 95% CI 2.06-4.89), Hodgkin lymphoma (aHR 4.83, 95% 2.61-8.93), and leukaemia (aHR 5.90, 95% CI 2.87-12.1). Lower CD4 cell counts at baseline were associated with higher rates of Kaposi sarcoma, cervical cancer, non-Hodgkin and Hodgkin lymphoma. Infection-related cancers are the most common cancer types among AYALWH in South Africa. The burden of these cancers may be reduced through HPV vaccination, targeted HIV testing, early initiation of antiretroviral therapy, and improvement of treatment adherence

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