The State of the Art of Image Guided Superficial Radiation Therapy Treatment of Non-melanoma Skin Cancer in Outpatient Dermatology Clinics in the United States and Review of the Literature.

Abstract

Image guided superficial radiation therapy (IGSRT) is a novel technology which combines traditional superficial radiation therapy (SRT) with high resolution dermal ultrasound (HRDUS) to treat non-melanoma skin cancers (NMSC). Since development, IGSRT use has expanded dramatically in outpatient clinics. We review the IGSRT literature and state-of-the-art operating principles in US dermatologic practices. A literature search of electronic databases (Medline, Pubmed, Cochrane Library, Science Direct) combined with various authors' published and unpublished documents, procedures, and clinical experience with IGSRT were synthesized for this paper. Studies have demonstrated IGSRT consistently delivers high cure rates (> 99%) with low complications for early stage (stage0, I, or II) squamous cell and basal cell carcinomas. Control rates are statistically superior to non-image guided SRT and external beam radiation (XRT) as well as Mohs micrographic surgery (MMS). This improvement is attributed to invivo dermal tumor visualization via HRDUS and using an interdisciplinary approach to deliver care. IGSRT use in the dermatologic clinic for early stage NMSCs has become common practice and continues to expand. While the safety and cosmetic benefits of SRT/XRT have been long documented, IGSRT represents a significant leap forward in efficacy (statistically significant) by adding in vivo dermal tumor imaging. Results rival and appear on one study to surpass tumor control obtained with MMS. A contributing factor to the success may be the availability and use of an interdisciplinary team approach that includes dermatologists, radiation therapists, radiation oncologists, and medical physicists. The high tumor control rates, minimal side effects, favorable cosmesis, and ability to treat multiple lesions per session using IGSRT are establishing this modality as a standard first-line therapy for early stage NMSCs in dermatology clinics. IGSRT may represent the most effective option for the non-surgical treatment of early stage NMSC to date.