Radiotherapy in the Shadow of Shingles: Managing Non-Melanoma Skin Cancer in Postherpetic Fields

Cutaneous squamous cell carcinoma (cSCC) is a common form of non-melanoma skin cancer (NMSC), with incidence increasing in elderly and immunocompromised populations. Postherpetic neuralgia (PHN) is a chronic neuropathic pain condition that occurs following reactivation of the varicella–zoster virus and typically affects a single dermatome. In the skin, PHN occurs following re-infection with the varicella-zoster virus (VZV), also known as human herpesvirus-3 (HHV-3). It usually takes a dermatomal distribution. We report on the successful treatment of a 15 mm biopsy-proven painful and tender in-situ cutaneous squamous cell carcinoma (cSCC) arising within a symptomatic field of longstanding PHN in an 82-year-old male, immunosuppressed with chronic lymphocytic leukemia (CLL)and cognitive decline. Definitive superficial radiotherapy (SXRT) of 45 Gy in 15 fractions was delivered over 3 weeks, using a 5 mm standoff to avoid direct contact with hypersensitive skin. The patient tolerated treatment well and achieved a complete clinical response still present at six months post RT when death from other causes intervened with no significant acute toxicity. This case highlights the feasible use of SXRT for cSCC arising within a PHN-affected dermatomal field through applying stand off to reduce contact irritation during treatment.