Photodynamic Therapy in Primary Cutaneous Skin Lymphoma-Systematic Review

Background/Objectives: Primary cutaneous lymphomas (CLs) are a group of skin-limited lymphoproliferative disorders, including cutaneous T-cell (CTCLs) and B-cell lymphomas (CBCLs). Photodynamic therapy (PDT), a non-invasive, light-activated treatment, has gained attention as a skin-directed therapy for early-stage CLs due to its selectivity and favorable safety profile. This systematic review evaluates the current evidence on the clinical use of PDT in managing CLs. Methods: A systematic literature search was conducted in PubMed, Scopus, and Embase through 1 September 2024 following PRISMA guidelines. Search terms included "primary cutaneous skin lymphoma", "CTCL", "CBCL", "mycosis fungoides", "lymphomatoid papulosis", and "photodynamic therapy". After screening 1033 records, 30 studies were included. Data were extracted and categorized by lymphoma subtype and clinical outcomes. Results: Of the included studies, 23 focused on mycosis fungoides (MF), 5 on lymphomatoid papulosis (LyP), and 2 on CBCL. PDT demonstrated notable clinical efficacy in early-stage and localized disease, particularly MF, using methyl aminolevulinate (MAL) or 5-aminolevulinic acid (5-ALA) as photosensitizers. Adjunctive techniques like microneedling and laser-assisted delivery improved treatment outcomes. PDT was generally well tolerated, with mild, transient side effects; rare complications such as localized neuropathy were reported. Conclusions: PDT is a promising, non-invasive treatment for early-stage CLs, especially MF and indolent CBCL variants. While current evidence supports its safety and effectiveness, further comparative and prospective studies are needed to refine protocols, evaluate long-term efficacy, and compare different photosensitizers.