Is tanning ever good for you? (CTCL)

Cutaneous T-cell Lymphoma is a category of diseases encompassing all lymphomas that are limited to the skin. There are multiple types of CTCL with different histological and clinical features. Emedicine has a simple overview of the different types, how they present, and whether they are typically indolent or aggressive. Mycosis fungoides is the most common type of CTCL and is predominantly an indolent disease.

A lot of research has been done on light therapy for early-stage Mycosis fungoides, and this is generally accepted as an effective first-line treatment. Both PUVA and UVB have been shown effective, but PUVA is associated with more side effects (erythema, carcinogenicity, nausea). In this study narrowband UVB and PUVA are compared.

Diederen PV, van Weelden H, Sanders CJ, Toonstra J, van Vloten WA. Narrowband UVB and psoralen-UVA in the treatment of early-stage mycosis fungoides: a retrospective study. J Am Acad Dermatol. 2003 Feb;48(2):215-9.

Narrowband UVB was found to have similar treatment efficacy and disease-free periods as PUVA.

Proposed mechanisms of action for narrowband UVB:
- increases allo-activating and antigen-presenting capabilities of Langerhans cells
- increases Il-2 and IL-6 production by keratinocytes
- increases TNF
- suppresses neoplastic T cells
- upregulates immune system

Propsed mechanisms of action for PUVA:
- mitotic inhibition
- killing neoplastic T cells
- psoralen might damage cell organelles or alter the immune system

In this study, PUVB, UVB, and PUVA are compared.

El-Mofty M, El-Darouty M, Salonas M, Bosseila M, Sobeih S, Leheta T, Nada H, Tawdy A, Amin I, El-Enany G. Narrow band UVB (311 nm), psoralen UVB (311 nm) and PUVA therapy in the treatment of early-stage mycosis fungoides: a right-left comparative study.Photodermatol Photoimmunol Photomed. 2005 Dec;21(6):281-6.

PUVB was not shown to have a significant advantage over UVB.

Caution should be used with light therapy treatments because of the risk of later carcinogenicity.