Radiotherapy May Exacerbate Anti‐Programmed Cell Death 1 Treatment-Induced Vitiligo: A Case Report

Immunotherapy with PD‐1 checkpoint inhibitors, combined with radiotherapy (RT), has shown potential for cancer treatment but is associated with immune-related adverse events (irAEs). This case highlights exacerbation of vitiligo as an irAE during combined PD-1 inhibitor and RT therapy. A stage IIIb rectal cancer patient underwent PD‐1 inhibitor therapy combined with RT. Clinical outcomes and adverse effects were analyzed. Vitiligo lesions worsened post-RT, suggesting systemic immune activation. Remarkable repigmentation was observed after appropriate intervention, with a clinical complete response to cancer therapy. The case suggests that irAEs, though challenging, may indicate favorable clinical responses.