HIV infection increases risk of melanoma

HIV infection is associated with an increased risk of melanoma, according to the results of a meta-analysis published in PLOS ONE. Overall, people living with HIV had a 26% increase in their relative risk of melanoma compared to the general population, the risk increasing by 50% for white-skinned people with HIV. The increased risk was statistically significant in white-skinned people diagnosed with HIV and of borderline statistical significance for all people diagnosed with HIV.

The authors recommend that fair-skinned people living with HIV should be regularly screened for suspicious skin lesions and should also be warned about the dangers of prolonged exposure to the sun.

Melanoma (skin cancer) diagnoses have increased markedly in the UK and many other countries in recent years. There is also evidence suggesting that people living with HIV have a higher risk of developing this skin cancer compared to individuals in the general population. Studies conducted before effective antiretroviral therapy became available in the mid-1990s showed that having HIV increased the relative risk of melanoma by approximately a quarter.

However, it is uncertain whether people living with HIV continue to have an increased risk of melanoma in the era of effective antiretroviral treatment.

A team of Australian and UK investigators therefore conducted a systematic review and meta-analysis, looking at the association between HIV and the relative risk of melanoma in the periods before and after potent HIV therapy became available.

The investigators’ analysis included cohort studies involving adult patients.

A total of 21 studies met their inclusion criteria. These were conducted between 1999 and 2013. Most (twelve) were conducted in the United States, eight in Europe and one in Australia. Most of the studies reported on cohorts of patients with HIV and those diagnosed with AIDS, but six studies defined their study population as patients with AIDS. The majority of studies (16) were population based, most of the patients being men (76-92%). One study included only men who have sex with men; one study included women only; a single study was restricted to veterans and two studies reported on single-clinic patient cohorts.

The median duration of follow-up ranged between two and ten years.

Eight studies presented melanoma estimates for the period before effective HIV therapy became available, the others gave estimates for the period after potent antiretroviral treatment was introduced. Overall, the standard of research was high and 57% of the studies were assessed as high quality and the others were of moderate quality. The most common limitation was a failure to control for ethnicity.

Pooled results showed that, in the era of effective antiretroviral treatment, HIV or AIDS was associated with an increase of borderline significance in the relative risk of melanoma (1.26; 95% CI, 0.97-1.64). This was significant in studies that considered ethnicity (1.50; 95% CI, 1.12-2.01). There was significant heterogeneity between the findings of these studies (p = 0.004).

Examination of data from the pre-therapy era showed that HIV or AIDS significantly increased the overall risk (1.26; 95% CI, 1.11-1.43) of melanoma and that the risk was also significantly increased in studies that controlled for ethnicity (1.28; 95% CI, 1.10-1.49).

These findings remained robust in sensitivity analyses.

“Taking into account the potential confounding effects of ethnicity, our findings show that risk of melanoma in those with HIV/AIDS remains elevated in the HAART [highly active antiretroviral therapy] era, with a 50% increased risk,” comment the authors. “The increased risk of melanoma in populations with HIV/AIDS may be related to effects of HIV infection on the immune system although these are complex, including not only immunodeficiency, but also chronic immune activation and inflammation, and immune dysfunction and senescence [ageing].”

They conclude, “white skinned people with HIV/AIDS would benefit from regular screening of the skin for suspicious pigmented lesions, and since they also have a significantly increased risk of developing keratinocyte skin cancers (at least two-fold) they should be counselled to avoid excessive sun exposure.”