Skin cancer appears to be more common among HIV-positive compared with HIV-negative people, according to a poster presented on Monday at the Fourth International AIDS Society Conference on HIV Treatment, Pathogenesis and Prevention.
Skin cancers are known to occur at higher rates in people with immune suppression, including organ transplant recipients. The incidence of Kaposi’s sarcoma of the skin in HIV-positive people has declined dramatically since the advent of highly active antiretroviral therapy (HAART). But some studies suggest that other types of skin cancer are more common or more aggressive in people with HIV.
Increased cancer rates in HIV-positive people might be due to impaired T-cell immune “surveillance” against cancer cells or failure to control cancer-causing viruses such as human papillomavirus (HPV).
American researchers analysed data from a prospective observational database including information on 4,566 HIV-positive participants, comparing the skin cancer incidence in this groups versus the incidence in the general HIV-negative US population as determined from cancer registries and recent studies.
Skin cancers were defined as cutaneous Kaposi’s sarcoma, malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. Recurring cancers were counted only once. Individuals who had cancer before they were diagnosed with HIV were excluded from the analysis
The HIV-positive database covered 27,385 person years (PY) of observation accumulated from patients treated between 1987 and 2006. The mean age was 29 years (range 17-75 years), 44% were white, and 45% were African-American.
Among the 4,507 HIV-positive patients included in the analysis, 260 developed skin cancer, for an incidence rate of 5.8%. These included 201 new cases of Kaposi’s sarcoma, 48 basal cell carcinomas, 13 malignant melanomas, and 7 squamous cell carcinomas. Nine patients developed more than one type of skin cancer.
Just over 80% of all skin cancers occurred prior to the introduction of effective triple-combination antiretroviral therapy, and the vast majority of these were cases of Kaposi’s sarcoma. The incidence of Kaposi’s sarcoma declined significantly after the introduction of HAART, from 1,590 to 180 cases per 100,000 PY (p
However, the combined rate of other types of skin cancer was similar over the study period: 300 cases per 100,000 PY in the pre-HAART period compared with 220 cases per 100,000 PY since the advent of HAART (p>0.05). Therefore, cancers other than Kaposi’s sarcoma accounted for a higher proportion of all skin cancers in the HAART era.
The rate of basal cell carcinoma, at 200 cases per 100,000 PY, was 2.3-fold higher than that seen in the HIV-negative population, and the rate of melanoma was elevated by 3.1-fold compared with the general population. Squamous cell cancer, however, did not occur more often in people with HIV.
Multivariate analysis showed that increasing age, male sex and white race were significant predictors of skin cancers other than Kaposi’s sarcoma. The study also showed a trend towards a higher rate of skin cancer in people with a history of HPV infection, but this did not reach statistical significance.
Having a high CD4 cell count did not appear to protect against skin cancer. The average CD4 cell count at which cancer occurred was 432 cells/mm3. Nadir (lowest-ever) CD4 cell count, which gives a better indication of the degree of past immunodeficiency, also did not predict development of skin cancer. Neither were use of antiretroviral therapy and undetectable HIV viral load associated with a lower skin cancer risk.
Based on these results, the researchers concluded, “Skin cancers were predominantly due to [Kaposi’s sarcoma] in the pre-HAART era, but now are mostly basal carcinomas and melanomas, which occur at higher rates among HIV-infected persons than the general population.”
They suggested that regular skin cancer screening for people with HIV should be considered, especially in light of the aging of the HIV-positive population.
Crum-Cianflone N et al. Increased incidence of skin cancers among HIV-infected persons. Fourth International AIDS Society Conference on HIV Treatment, Pathogenesis and Prevention, Sydney, abstract MoPeB086, 2007.