Carcinogenic risks of Psoralen UV-A therapy and Narrowband UV-B therapy in chronic plaque psoriasis: a systematic literature review
ABSTRACT Oral 8-methoxypsoralen-UV-A (PUVA) and narrowband UV-B (NB-UVB or UVB TL-01) are effective and widely used treatments for chronic plaque psoriasis. Although the role of PUVA therapy in skin carcinogenesis in humans with psoriasis has been clearly demonstrated, there is still controversy regarding the risk of skin cancer with NB-UVB. Furthermore, there is no clear evidence about the maximum cumulative number of sessions not to be exceeded in a lifetime.
To assess the respective cutaneous carcinogenic risks of PUVA or NB-UVB in psoriasis; to estimate the respective dose-relationship between skin cancers and PUVA or NB-UVB; to estimate a maximum number of sessions for PUVA or NB-UVB not to be exceeded in a lifetime.
A systematic literature search was carried out in Medline, Embase and Cochrane Library databases from1980 to December 2010 in English and French, with the keywords 'Psoriasis' AND 'UVB therapy' AND 'UVA therapy' AND 'cancer' AND 'skin' OR 'neoplasm' OR 'cutaneous carcinoma' OR 'melanoma'.
Of 243 identified references, 49 published studies were included. Most of them (45/49) concerned PUVA therapy, with 41 assessing the risk of non-melanoma skin cancers (NMSC) following PUVA. All publications referring to the US prospective PUVA follow-up study revealed an increased risk of NMSC with the following characteristics: risk most pronounced for squamous cell carcinomas developing even with low exposures and increasing linearly with the number of sessions, tumors occurring also on non-exposed skin including invasive penile tumors, risk persisting after cessation of treatment. An increased risk of basal cell carcinomas was observed in patients receiving more than hundred PUVA sessions. The four prospective European studies selected in our review and most of the pre-1990 European and US retrospective studies failed to find a link between exposure to PUVA and skin cancer. Only the most recent cohorts, including three large long-term retrospective European studies comparing records with their respective national cancer registries reported on an independent increased risk of NMSC with PUVA, The risk was lower as compared to the US prospective PUVA follow-up study. Six studies assessed the risk of melanoma following PUVA therapy: two of the three US publications coming from the same PUVA prospective follow-up study revealed an increased risk with more than doubled incidence of both invasive and in situ melanoma among patients exposed to at least 200 PUVA treatments compared with patients exposed to lower doses, whereas the three retrospectives European studies, comparing the incidence of melanoma in PUVA users with national cancer registers, did not find any increased risk of melanoma. No increased risk of skin cancer was evidenced in the four studies specifically assessing the potential carcinogenic risk of NB-UVB.
There is an increased risk of skin cancer following PUVA, shown by both US and European studies. The greater risk measured by the US studies may be at least partly explained by high UVA dose exposure and the lighter phototypes of the treated patients. The lack of prospective studies in psoriasis patients treated with NB-UVB constitutes a barrier to the robust assessment of carcinogenic risk of this phototherapy technique.
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ABSTRACT: Introduction: The application of light as a stimulus in pharmaceutical systems and the associated ability to provide precise spatiotemporal control over location, wavelength and intensity, allowing ease of external control independent of environmental conditionals, has led to its increased use. Of particular note is the use of light with photosensitisers.Areas covered: Photosensitisers are widely used in photodynamic therapy to cause a cidal effect towards cells on irradiation due to the generation of reactive oxygen species. These cidal effects have also been used to treat infectious diseases. The effects and benefits of photosensitisers in the treatment of such conditions are still being developed and further realised, with the design of novel delivery strategies. This review provides an overview of the realisation of the pharmaceutically relevant uses of photosensitisers, both in the context of current research and in terms of current clinical application, and looks to the future direction of research.Expert opinion: Substantial advances have been and are being made in the use of photosensitisers. Of particular note are their antimicrobial applications, due to absence of resistance that is so frequently associated with conventional treatments. Their potency of action and the ability to immobilise to polymeric supports is opening a wide range of possibilities with great potential for use in healthcare infection prevention strategies.Expert Opinion on Drug Delivery 09/2014; 12(1). DOI:10.1517/17425247.2015.962512 · 4.12 Impact Factor
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ABSTRACT: Background: Cellular combinations in the same neoplasm can have intriguing physiopathological implications, which may be useful to better understand the biology of the diseases. Main observations: Urticaria pigmentosa in association with eruptive melanocytic nevi was observed in a female patient. Maculopapular lesions extended at the base of different melanocytic nevi and the histopathological examination revealed the presence of a mast cell population in the papillary and reticular dermis combined with overlying melanocytic nevi. The re-evaluation of a melanoma removed three years before revealed the presence of the same pathological features. Immunohistochemical assays showed a strong positivity to Giemsa, Toluidine blue and CD-117 in the mast cells, while a S-100 reaction was observed in the melanocytic population. Conclusions: We discuss possible pathogenetic linkage between cutaneous mastocytosis and melanoma.Journal of Dermatological Case Reports 09/2014; 8(3):70-74. DOI:10.3315/jdcr.2014.1179
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ABSTRACT: Phototherapy is a first-line option for the treatment of moderate to severe psoriasis. Systematic reviews indicate near comparable efficacy of the different forms of phototherapy. Localized phototherapy can be an adjunctive treatment of recalcitrant plaques during systemic treatment of psoriasis. More than 200 psoralen-UV-A therapy treatment sessions is associated with an increased risk of keratinocytic cancers, whereas no increased risk has been demonstrated for narrow-band UV-B therapy. The mechanism of action of phototherapy in psoriasis is via inhibition of keratinocyte proliferation; induction of apoptosis in keratinocytes, dendritic, and T cells; and inhibition of Th1 and Th17 pathways, but activation of Th2.Dermatologic Clinics 11/2014; 33(1). DOI:10.1016/j.det.2014.09.007 · 1.43 Impact Factor