HIV and cancer in the age of ART
Although the risk of developing cancer is decreasing for people living with HIV as antiretroviral treatment (ART) improves, it remains higher for certain cancers – and as ART expands, this burden is expected to grow.
As effective antiretroviral treatment (ART) sees more and more people with HIV living for longer, studies on the relationship between HIV and common diseases such as cancer are becoming increasingly important.
The USA HIV/AIDS Cancer Match Study, the largest ever study of its kind, analysed 450,000 HIV and cancer records from eight American states and Puerto Rico between 1996, when effective ART was rolled out, and 2012.
The study, published in the The Lancet, found that although the overall risk of developing cancer faced by people living with HIV has decreased in the ART-era, people with HIV are still more at risk of developing certain cancers than people who are HIV negative, especially cancers that have viral causes. This risk is higher for all people living with HIV, not just those who have developed AIDS.
This risk remains greatest for AIDS-defining cancers caused by a virus, such as Kaposi’s sarcoma and non-Hodgkin lymphoma, although effective ART has greatly reduced the number of people with HIV who develop these types of cancers and is likely to continue to do so.
People living with HIV also face a greater risk than HIV negative people of developing most other virus-related cancers, such as anus and liver cancer, and some cancers that are not caused by viruses, such as lung cancer. Encouragingly, however, this risk reduced during the 17 years of the study, presumably as a result of continuing improvements in ART. The risk of developing lung cancer could also be linked to high smoking rates among people living with HIV, although this was not examined by the study.
The study found people living with HIV were no more at risk than HIV negative people of developing common cancers such as breast, prostate and kidney cancer. Indeed, risks for some of these cancers were actually lower among people living with HIV than the general population. Again, factors relating to these cancers were not analysed.
As the expansion of effective ART results in more and more people with HIV becoming virally suppressed, this study suggests that reductions in certain cancers, particularly AIDS-defining cancers, are likely to continue.
Yet the study’s authors point to the fact that, despite the many health benefits of viral suppression, someone with HIV who is virally suppressed will still have a compromised immune system. This means they may be more susceptible to the inflammations, viral infections, carcinogens and mutations that cause cancer than other people. As viral suppression results in more people with HIV reaching an age where the risk of cancer generally increases, the question of whether they will be disproportionately affected needs further examination.
In the meantime, efforts to prevent cancer among people living with HIV, such as through interventions that address smoking and alcohol use, must be made. Extensive and on-going cancer screening for people living with HIV, as well as treatment for viruses such as hepatitis C and B, must also be scaled-up.
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