Narrow-band Ultraviolet B Exposure Research Articles

Incidence of skin cancers in 3867 patients treated with narrow-band ultraviolet B phototherapy

Narrow-band ultraviolet B (NB-UVB) phototherapy is a widely used treatment. Psoralen-UVA photochemotherapy (PUVA) increases skin cancer risk and some animal studies have raised the possibility of an increased risk with NB-UVB. The risk of skin cancer in humans following treatment with NB-UVB is unknown. This current analysis forms part of an ongoing study ultimately aiming to define the long-term carcinogenic risk of NB-UVB treatment in humans. Details of all patients receiving NB-UVB treatment until 31/12/2002 in Tayside, Scotland, were accessed from a treatment database and linked to the Scottish Cancer Registry. Indirect standardization was used to compare skin cancer incidence in the study population with age and sex matched cancer registry data for the Tayside population. We also assessed the effect of NB-UVB exposure treatment numbers on the risk of developing skin cancer. Of 4690 records reviewed, 4665 were suitable for analysis with 3886 records linked with the cancer registry and 3867 followed-up for at least 6 months before 31/12/02 (the date at which cancer registration was deemed to be complete). The median number of NB-UVB treatments was 29 with 352 patients receiving > or = 100 treatments. The study gave 24,753 person-years of follow up. First skin cancers recorded in study patients were 27 basal cell carcinomas (BCC), seven squamous cell carcinomas (SCC) and six melanomas. No association was found between NB-UVB exposure alone (without PUVA) and any skin cancer. For NB-UVB and PUVA treated patients there was an association with BCC, with 27 BCCs found compared with 14.1 expected in the matched population. We found no significant association between NB-UVB treatment and BCC, SCC or melanoma. There was a small increase in BCCs amongst those also treated with PUVA. These reassuring results do not demonstrate the early increase in skin cancers that was found associated with PUVA treatment. However, cautious interpretation is required as the cohort contained relatively few patients who had a high treatment number and because the slow evolution of skin cancers may result in a delayed incidence peak. Ongoing risk assessment is therefore essential.

Narrow-Band UVB Induces More Carcinogenic Skin Tumors than Broad-Band UVB through the Formation of Cyclobutane Pyrimidine Dimer

Phototherapy with narrow-band UVB (NB-UVB), with a peak exclusively at 311 nm wavelength, has been found to be more effective in treating a variety of skin diseases than conventional broad-band UVB (BB-UVB). To assess the difference in carcinogenic activity between NB-UVB and BB-UVB, we investigated skin tumor formation by irradiating albino hairless, Ogg1 knockout mice and C57BL/6J wild counterparts with these two UV sources. We found that the ratio of malignant skin tumors induced by NB-UVB was significantly higher than that induced by BB-UVB. There was no significant difference in carcinogenicity of skin tumor induced by NB-UVB between Ogg1 knockout and wild-type mice. To investigate the possible cause of different carcinogenic activity by the different UV sources, we examined three types of DNA damage: cyclobutane pyrimidine dimer (CPD), (6-4) photoproduct, and 8-oxoguanine (8-oxoG) induced by each UV source. We found that CPD formation following a minimum erythema dose (MED) by NB-UVB was significantly higher than that following 1 MED by BB-UVB, whereas the formation of (6-4) photoproducts and 8-oxoG following BB-UVB was significantly higher than those following NB-UVB exposure. These results suggest that CPD formation is closely related to the higher carcinogenic characteristics of NB-UVB. JID JOURNAL CLUB ARTICLE: For questions, answers and open discussion about this article please go to http://network.nature.com/.

Provocation testing in polymorphic light eruption using fluorescent ultraviolet (UV) A and UVB lamps

Provocation testing is frequently performed during investigation of patients with suspected polymorphic light eruption (PLE). Techniques are not standardized between centres. We sought to evaluate the efficacy of different fluorescent ultraviolet (UV) radiation lamps for provocation testing in PLE. We analysed results in 68 patients referred consecutively for phototesting in whom a diagnosis of PLE seemed likely based on clinical history. Patients' case notes were reviewed and responses recorded to provocation testing on forearm skin over three consecutive days using broadband UVA, narrowband and broadband UVB lamps. A positive papular response to broadband UVA exposure was seen in 38 patients [56%, estimated 95% population confidence interval (CI) 43-67.9]. Thirty-four patients (50%) had a positive papular response to narrowband UVB exposure (95% CI 37.6-62.4). The probability of a positive provocation test following irradiation with both lamps was 80.9% (95% CI 69.5-89.4). From April 1999, 34 patients also had provocation testing with broadband UVB. Although six patients (18%) had a positive papular response, they all showed a positive response to one or both of the other lamp types. Provocation testing with fluorescent UVA and UVB lamps is a cheap and readily available method that can be used as a diagnostic aid to investigate patients with suspected PLE. Using both broadband UVA and narrowband UVB lamps for testing increases the likelihood of confirming the diagnosis than if either lamp is used alone.

QV002 A new task for clinical microbiology: Proposing ICD-codes of diagnoses of infectious diseases or complications

Phototherapy with narrow-band UVB (NB-UVB), with a peak exclusively at 311 nm wavelength, has been found to be more effective in treating a variety of skin diseases than conventional broad-band UVB (BB-UVB). To assess the difference in carcinogenic activity between NB-UVB and BB-UVB, we investigated skin tumor formation by irradiating albino hairless, Ogg1 knockout mice and C57BL/6J wild counterparts with these two UV sources. We found that the ratio of malignant skin tumors induced by NB-UVB was significantly higher than that induced by BB-UVB. There was no significant difference in carcinogenicity of skin tumor induced by NB-UVB between Ogg1 knockout and wild-type mice. To investigate the possible cause of different carcinogenic activity by the different UV sources, we examined three types of DNA damage: cyclobutane pyrimidine dimer (CPD), (6-4) photoproduct, and 8-oxoguanine (8-oxoG) induced by each UV source. We found that CPD formation following a minimum erythema dose (MED) by NB-UVB was significantly higher than that following 1 MED by BB-UVB, whereas the formation of (6-4) photoproducts and 8-oxoG following BB-UVB was significantly higher than those following NB-UVB exposure. These results suggest that CPD formation is closely related to the higher carcinogenic characteristics of NB-UVB. JID JOURNAL CLUB ARTICLE: For questions, answers and open discussion about this article please go to http://network.nature.com/

Comparison of psoralen-UVB and psoralen-UVA photochemotherapy in the treatment of psoriasis

Background: PUVA treatment of psoriasis is usually given with broad-band fluorescent UVA lamps. Narrow-band UVB exposure after oral methoxsalen has been shown to achieve a greater therapeutic response in psoriasis than identical UVB exposure given without psoralen. Objective: The purpose of this study was to compare conventional PUVA with psoralen-UVB therapy in psoriasis. Methods: We studied 100 patients with plaque-type psoriasis who were randomly selected to receive either conventional psoralen-UVA or psoralen-UVB treatment. Results: No significant difference was found between the two treatments in the proportion of patients whose skin cleared during treatment or in the number of exposures required for clearance of psoriasis. As expected, the cumulative UV dose for clearance was smaller in the group treated with UVB compared with those receiving UVA. Side effects and disease status at 3 months after the end of treatment were similar for the two groups. Conclusion: Psoralen-UVB treatment of psoriasis is as effective as conventional PUVA. The mechanism of psoralen–311 nm UVB action on psoriasis requires study to predict the long-term safety of this treatment. (J Am Acad Dermatol 1997;36:577-81.)