Phototherapy treatment for psoriasis, eczema not linked to increased skin cancer risk

Key takeaways:

• Patients with psoriasis or eczema used narrowband-UVB, broadband-UVB or combined UVAB phototherapy.
• Skin cancer incidence rates in this patient population were comparable with the general population.

Patients treated with phototherapy without psoralens do not experience higher incidence rates of skin cancer compared with the general population, according to a study.

“Patients with skin conditions, such as psoriasis and eczema are often treated with ultraviolet light therapy, such as ultraviolet-B phototherapy,” Elle Wang, MSc, of the department of dermatology and skin science at The University of British Columbia and the Photomedicine Institute at Vancouver Coastal Health Research Institute in Canada, and colleagues wrote. “Ultraviolet radiation from excessive sun exposure is known to increase the risk of skin cancer. However, whether patients treated with ultraviolet phototherapy have a higher risk of skin cancer is not fully understood.”

In this retrospective study, the authors evaluated the association between different types of phototherapy without psoralens and skin cancer incidences among patients with psoriasis and eczema.

Of 3,506 patients (psoriasis, 60.9%; eczema, 26.4%) that underwent broadband-ultraviolet-B (UVB), narrowband-UVB and/or combined ultraviolet A and broadband-UVB (UVAB) phototherapy in this study, 79 were diagnosed with a total of 170 tumors including melanoma (n = 17), squamous cell carcinoma (SCC; n = 33) and basal cell carcinoma (BCC; n = 120).

Results showed that the overall patient-based age-standardized incidence rate (ASIR) of skin cancer was 149 per 100,000 person-years (95% CI, 112-187) and the tumor-based ASIR of skin cancer was 264 per 100,000 person-years (95% CI, 219-309).

The authors did not detect a significant difference between tumor-based ASIRs for melanoma, SCC and BCC among patients undergoing phototherapy and the general population.

Additionally, there was no significant difference in patient-based and tumor-based ASIRs of skin cancer between phototherapy-treated patients with psoriasis and eczema.

While patients with a history of immunosuppressive medications may be predisposed to skin cancer, there was no significant increased risk for skin cancer detected in these patients compared with patients that were not treated with immunosuppressive medications (OR = 0.96; 95% CI, 0.4-2).

“No increased risk of melanoma, SCC and BCC compared to the general population was found in patients receiving phototherapy with [narrowband-UVB], [broadband-UVB] and UVAB,” the authors wrote. “This suggests ultraviolet phototherapy can be considered a relatively safe treatment option.”