For the estimated 1-2% of the global population living with vitiligo, narrowband UVB phototherapy offers meaningful hope for repigmentation — yet the same biological machinery that restores pigment cells harbors potential for malignant transformation. Understanding precisely how ultraviolet radiation walks this therapeutic tightrope has real implications for long-term treatment planning.
This review, published in Frontiers in Medicine, synthesizes current understanding of how ultraviolet radiation exerts fundamentally contradictory effects on melanocyte biology. On the restorative side, calibrated NB-UVB and excimer laser exposures stimulate melanocyte stem cell activation, proliferation, and upregulation of melanin synthesis pathways — including the MC1R–cAMP–MITF signaling axis — enabling repigmentation of depigmented lesions. On the damaging side, cumulative or poorly dosed UVR induces reactive oxygen species accumulation, cyclobutane pyrimidine dimer formation, p53 pathway disruption, and genomic instability — the same cascade implicated in melanoma initiation. The review also examines combination strategies gaining clinical traction, including JAK1/2 inhibitors targeting the IFN-γ/JAK/STAT autoimmune pathway, platelet-rich plasma for its growth factor-mediated cytoprotection, and autologous cellular grafting techniques for refractory cases.
This review arrives at a clinically meaningful moment. The long-term melanoma risk associated with phototherapy in vitiligo patients remains genuinely unresolved — epidemiological data are conflicting, partly because vitiligo itself may confer some immunosurveillance advantage against melanoma through heightened melanocyte-directed immune activity. The introduction of topical and oral JAK inhibitors into vitiligo management now complicates the picture further, since these agents carry their own immunomodulatory profiles that could theoretically influence cancer risk. As a narrative review rather than a meta-analysis or clinical trial, the piece synthesizes existing evidence without generating new effect-size data, limiting its evidentiary weight. Still, its integrated mechanistic framing — connecting phototherapy dosing, melanocyte homeostasis, and carcinogenesis risk within a single model — offers a useful conceptual scaffold for dermatologists navigating treatment escalation decisions.