Long-Term Recurrence Rate of Large and Difficult to Treat Cutaneous Squamous Cell Carcinomas after Superficial Radiotherapy

Background: Surgical excision is the gold standard for cutaneous squamous cell carcinoma (cSCC), however its application is limited in specific cases. Superficial radiotherapy (RTx) is an alternative treatment option, but long-term follow-up data are limited. Objective: To determine the outcome of superficial RTx of cSCC in correlation to histological differentiation grade and tumor localization. Methods: The outcome of 180 large cSCCs after superficial RTx between 1960 and 2004 was retrospectively reviewed. Results: Mean tumor size was 3.5 cm² (SD 7.5) and mean follow-up period was 4.9 years (SD 4.7). Relapse-free survival was 95.8 and 80.4% after 1 and 10 years. Two-year relapse-free survival was 94.8% for good, 88.9% for moderate and 85.7% for poor differentiated tumors. Five-year relapse-free survival was highest in cSCCs located around the eyes (100%) and cheeks (90.9%). Conclusion: Superficial RTx is an effective alternative for cSCC if surgery is difficult due to localization or concomitant disease.