Analysis of Image-Guided Superficial Radiation Therapy (IGSRT) on the Treatment of Early Stage Non-Melanoma Skin Cancer (NMSC) in the Outpatient Dermatology Setting

Abstract

Interest in image-guidance superficial radiation therapy (IGSRT) for the treatment of early-stage Non-Melanoma Skin Cancer (NMSC) has resurfaced given its low complication rates, superior cosmesis and local control and cure rates. Additionally, it has been recommended by the American Academy of Dermatology (AAD) for early-stage NMSC in patients who are considered poor surgical candidates. Methods: 1899 NMSC lesions were treated with energies ranging from 50 to 100 kilovoltage (kV), for a mean of 20.2 fractions, and treatment dose of 5364.4 centigray (cGy). Lesions were treated for a mean of 7.5 weeks and followed for 65.5 weeks. The Radiation Treatment Oncology Group (RTOG) toxicity scoring system was used to grade acute toxicities. Patients were followed after treatment completion until No Evidence of Disease (NED) was achieved or failure/recurrence. SAS studio was used to conduct Kaplan-Meier analysis to calculate local control rates and account for differences in follow-up intervals. A log-rank test was used to calculate statistical differences between histologies. Results: 95% of lesions received a RTOG grade of 1 or 2. Absolute lesion control was achieved in 99.7% of the patients after an average of 7.5 weeks of treatment, with a stable control rate of 99.6% when the follow-up duration was over 12 months. Conclusion: IGSRT has a high safety profile, can achieve superior cosmesis and should be considered first-line for treating early-stage NMSC tumors as cure rates have been shown to be effective in all NMSC on early follow-up.