Background: Basal cell carcinoma and squamous cell carcinoma are the most common types of non-melanoma skin cancer.1 Superficial radiation therapy (SRT) is a treatment modality that utilizes low-energy x-rays to disrupt cell mitosis directly and indirectly.2 This method of treatment offers advantages for select patients. While this technique has been utilized for over a century, it has recently begun to gain favor in clinical practice.1,3 Although SRT has shown favorable outcomes with a low risk of complications, it still poses a risk for adverse events.1,3,4 The frequency and severity of adverse events are not well-defined with SRT delivered technology with an image-guided approach utilizing high-frequency ultrasound capabilities.3,5
Methods: A retrospective chart review study was performed on patients treated with image-guided SRT at an academic dermatology clinic between December 2018 to December 2021. Demographic information and medical history related to the population were analyzed as part of the data set. All patients were questioned about risk factors for radiation complications, including a history of cutaneous lupus, prior to SRT. Complications were defined as adverse events within the treatment site persisting beyond the treatment period. Adverse events including erythema, desquamation, radiation dermatitis, and radiation necrosis were collected during the treatment period and subsequent follow-up visits. The primary endpoint was any dermatologic diagnosis or condition requiring treatment beyond the 2-week follow-up visit.
Results: Three of 165 patients treated with SRT during the reviewed dates experienced adverse events beyond erythema and desquamation during the treatment period. Two patients experienced ulceration of the lower extremities. Both patients with ulcerations had venous stasis with chronic edema. One patient developed radiation-induced cutaneous lupus erythematosus. The patient who developed cutaneous lupus after therapy had no prior history systemic or cutaneous lupus.
Conclusion: Treatment complications were rare, and all were expected complications of radiation therapy. They occurred despite precautions intended to minimize these complications. High-frequency ultrasound image-guided SRT is a well-tolerated treatment for non-melanoma skin cancer. Conducting further controlled studies on adverse events, risk factors, treatments, and prevention strategies for non-melanoma skin cancer would enhance patients’ ability to make informed decisions regarding their treatment options.
References: 1. McGregor S, Minni J, Herold D. Superficial Radiation Therapy for the Treatment of Nonmelanoma Skin Cancers. J Clin Aesthet Dermatol. Dec 2015;8(12):12-4. 2. Gianfaldoni S, Gianfaldoni R, Wollina U, Lotti J, Tchernev G, Lotti T. An Overview on Radiotherapy: From Its History to Its Current Applications in Dermatology. Open Access Maced J Med Sci. Jul 25 2017;5(4):521-525. doi:10.3889/oamjms.2017.122 3. Han H, Gade A, Ceci FM, Lawson A, Auerbach S, Nestor MS. Superficial radiation therapy for nonmelanoma skin cancer: A review. Dermatological Reviews. 2023;3(6):409-417. doi:10.1002/der2.174 4. Hernandez-Machin B, Borrego L, Gil-Garcia M, Hernandez BH. Office-based radiation therapy for cutaneous carcinoma: evaluation of 710 treatments. Int J Dermatol. May 2007;46(5):453-9. doi:10.1111/j.1365-4632.2006.03108.x 5. Yu L, Oh C, Shea CR. The Treatment of Non-Melanoma Skin Cancer with Image-Guided Superficial Radiation Therapy: An Analysis of 2917 Invasive and In Situ Keratinocytic Carcinoma Lesions. Oncol Ther. Jun 2021;9(1):153-166. doi:10.1007/s40487-021-00138-4