Immunosuppressed stem cell and organ TRs and HIV-positive patients have a higher risk of developing skin cancer compared with immunocompetent individuals. Risk factors for the development of skin cancer in immunodeficient patients are the same as those in the general population, with fair skin, sun exposure, and family history of skin cancer being the principal factors. Certain antiretroviral medications are reported to have a photosensitizing effect, or it might be that HIV infection itself has a photosensitizing effect, but these relationships have not yet been established in the greater literature. Although the rate of nonmelanoma skin cancer (NMSC) is increased in both groups, TRs have a markedly higher risk than people with HIV/AIDS. The incidence of NMSC in TRs can be as high as 34%. In the general population, basal cell carcinoma (BCC) is more common than cutaneous squamous cell carcinoma (cSCC). NMSC in the HIV-positive population demonstrates a similar distribution to BCC, occurring nearly three times as often as cSCC, whereas TRs develop cSCC more frequently than BCC. The risk of developing NMSC increases dramatically with longer posttransplant times; at 10 years after transplant, the prevalence of NMSC is 32%. Within the HIV-positive population, BCC is second behind KS as the most common cutaneous malignancy, with a prevalence of 1.8%. CD4 count does not correlate with the incidence or severity of BCC but may play a more significant role in the development of cSCC. An additional risk factor for the development of cSCC is the use of voriconazole in the treatment of invasive fungal infections in TRs and in patients with HIV. Several reports describe voriconazole-induced photosensitivity leading to accelerated development of cSCC, although the exact mechanism of phototoxicity and progression to cSCC remains unknown.
The evidence that links immunodeficiency to increased risk of melanoma is less clear than for NMSC. Conflicting evidence exists regarding whether melanoma incidence is elevated in TRs. Overall the data do suggest an increased risk for melanoma, but to a much lesser degree than that seen in NMSC. Treatment outcomes vary with the type of skin cancer. Compared with the general population, NMSC in immunocompromised patients—particularly cSCC—is more often invasive and aggressive with higher rates of metastasis and recurrence. Although more aggressive types of BCC in HIV-positive patients have been reported, standard excisional techniques result in cure rates similar to those of the general population. In contrast, cSCC is associated with higher mortality in immunosuppressed patients, with mortality around 3% in TRs and up to 50% in HIV patients who have metastatic cSCC. Melanoma also has more aggressive features in the setting of immune suppression, and shorter disease-free and overall survival rates have been demonstrated in HIV-positive patients. As in the management of KS, reduction of immunosuppression in TRs is associated with reduced incidence and improved outcomes for skin cancer. No clear guidelines have been established for the management of cSCC or melanoma in HIV patients, but local excision with early consideration for systemic therapy is generally recommended. Because of the aggressive nature of skin cancers in immunosuppressed patients, early detection with a low threshold for biopsy of suspicious lesions is recommended.
Source: Cummings Otolaryngology, 6E (2015)