Efficacy of Psoralen UV-A therapy vs. Narrowband UV-B therapy in chronic plaque psoriasis: a systematic literature review

Background Oral 8-methoxypsoralen-UV-A (PUVA) and Narrowband UV-B (NB-UVB or UVB TL-01) are well established treatments for chronic plaque psoriasis but there is limited evidence regarding their respective efficacy. Objectives To prepare for evidence-based recommendations concerning the practical use of oral 8-methoxypsoralen-UV-A and Narrowband UV-B in psoriasis, a systematic review to assess respective response rates, remission duration and predictive factors of efficacy was performed. Methods A systematic search was carried out in PubMed, Cochrane and Embase databases, using the key words 'Psoriasis', 'UVB therapy', 'UVA therapy' for the period from 1980 to December 2010. Results The initial literature search identified 773 articles. The final selection included 29 randomized controlled trials: 18 were about the efficacy of PUVA, eight about the efficacy of NB-UVB and three directly compared PUVA vs. NB-UVB. The response rate defined by 75% or more improvement in PASI was 80% with PUVA vs. 70% with NB-UVB. The meta-analysis of the three comparative studies found a higher probability of remission at 6 months with PUVA than with NB-UVB [OR = 2.73 (95% CI 1.19-6.27), P = 0.02]. The choice of initial dose, according to skin type, the minimal erythemal dose or minimal phototoxic dose, incremental regimen and periodicity of the sessions did not appear to be predictive factors of efficacy for PUVA or NB-UVB. Despite methodological limitations in trials, the number of sessions needed for psoriasis clearance appeared to be lower with PUVA than with NB-UVB (approx. 17 vs. 25, respectively). Conclusion PUVA and NB-UVB are both effective therapies in treatment of psoriasis. Our results suggest that compared with NB-UVB, PUVA tends to clear psoriasis more reliably, with fewer sessions, and provides with longer lasting clearance. However, the long-term safety of PUVA, especially its cutaneous carcinogenic risk, and the easier administration procedure often lead dermatologists to prefer NB-UVB as first line phototherapy treatment in plaque type psoriasis.