From the Guidelines
Image-guided Stereotactic Radiation Therapy (SRT) is a highly effective treatment option for skin cancer, offering cure rates of 93-96% for basal cell carcinomas, as reported in the NCCN clinical practice guidelines in oncology 1. When considering treatment options for skin cancer, it is essential to prioritize morbidity, mortality, and quality of life. In the case of image-guided SRT, this technique delivers precise, highly focused radiation to the tumor while sparing surrounding healthy tissue, resulting in minimal side effects and excellent cosmetic outcomes. Key benefits of image-guided SRT for skin cancer include:
- High cure rates, ranging from 93-96% for basal cell carcinomas, as reported in the NCCN clinical practice guidelines in oncology 1
- Minimal side effects, including skin redness, irritation, and temporary hair loss in the treated area
- Painless treatment, requiring no anesthesia or downtime
- Excellent cosmetic outcomes, making it an ideal option for cancers in cosmetically sensitive areas
- Reduced risk of recurrence, particularly for high-risk patients with substantial perineural involvement, as recommended by the NCCN panel 1 In terms of treatment specifics, image-guided SRT typically involves 5-20 sessions over 1-4 weeks, with each session lasting about 15-30 minutes. The radiation dose varies based on cancer type, size, and location, but commonly ranges from 45-70 Gy total, fractionated over the treatment course. The use of intensity-modulated RT (IMRT) has been gaining wide use in recent years, and proper support and training by medical physicists is essential to ensure adequate surface dose to the target area 1.
From the Research
Image Guided SRT for Skin Cancer
- Image guided superficial radiation therapy (IGSRT) is a novel technology that combines traditional superficial radiation therapy (SRT) with high resolution dermal ultrasound (HRDUS) to treat non-melanoma skin cancers (NMSC) 2.
- Studies have demonstrated IGSRT consistently delivers high cure rates (> 99%) with low complications for early stage (stage 0, I, or II) squamous cell and basal cell carcinomas 2, 3.
- IGSRT use in the dermatologic clinic for early stage NMSCs has become common practice and continues to expand, with high tumor control rates, minimal side effects, favorable cosmesis, and ability to treat multiple lesions per session 2.
Efficacy and Safety of IGSRT
- A study evaluating the efficacy and safety of IGSRT in treating 2917 invasive and in situ NMSC lesions found a 99.3% rate of local tumor control, with treatment being safe and well tolerated 3.
- Another study found that IGSRT provides durable disease control with acceptable toxicity for medically unfit high-risk head and neck skin cancer patients unable to undergo standard of care curative treatment approaches 4.
- A large retrospective cohort study compared 2-, 4-, and 6-year freedom from recurrence in biopsy-proven NMSC lesions treated with IGSRT and found overall freedom from recurrence rates of 99.68% at 2 years, 99.57% at 4 years, and 99.57% at 6 years, with no significant difference by age 5.
Resistance to Nonsurgical Treatments
- A review of resistance to nonsurgical treatments for nonmelanoma skin cancer, including radiotherapy, found that some tumors do not respond due to resistance, which may be primary or acquired 6.
- Study of the resistance processes is a broad area of research that aims to increase our understanding of the nature of each tumor and the biologic features that make it resistant, as well as to facilitate the design of new therapies directed against these tumors 6.