Image-Guided Superficial Radiation Therapy for Squamous Cell Carcinoma In Situ of the Nasal Ala in a High-Risk Surgical Candidate: A Case Report.

Nonmelanoma skin cancers (NMSCs), including squamous cell carcinoma in situ (SCCIS), are common and considered curable with early intervention; however, management must be individualized based on tumor characteristics and patient-specific factors. While surgical approaches such as Mohs micrographic surgery are the standard of care for high-risk anatomical sites, nonsurgical modalities are essential for patients with significant comorbidities. We present the case of an 80-year-old male with recurrent SCCIS of the right nasal ala whose medical history was significant for renal transplantation on chronic immunosuppressive therapy, chronic obstructive pulmonary disease (COPD) requiring supplemental oxygen, and impaired mobility, making him a poor surgical candidate for Mohs surgery or complex reconstruction. The patient elected treatment with image-guided superficial radiation therapy (IG-SRT), a noninvasive modality that incorporates high-resolution dermal ultrasound (HRDUS) for precise tumor measurement and treatment planning. Initial HRDUS demonstrated a tumor depth of 2.34 mm. He subsequently completed 20 fractions over six weeks, receiving a total dose of 5666.20 cGy. Expected radiation-induced skin changes developed during treatment, with a peak Radiation Therapy Oncology Group (RTOG) toxicity score of 2. Serial HRDUS demonstrated progressive tumor regression and no detectable residual tumor six weeks after treatment completion. The patient was pleased with the cosmetic outcome and experienced no alar distortion or airway compromise. This case highlights IG-SRT as a feasible, tissue-sparing treatment option for recurrent SCCIS in medically complex patients who are poor surgical candidates while emphasizing the value of HRDUS for treatment planning and response monitoring.