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Feature Story

Office-Based Surface Radiotherapy for the Dermatology Clinic: A Two-Case Study

March 2021

Standard of care for patients with nonmelanoma skin cancer (NMSC) remains to be surgical treatment. A number of techniques, including standard excision, Mohs micrographic surgery, and electrodesiccation and curettage, can all achieve clinically relevant results.1 So far in my career, I have surgically treated more than 25,000 skin cancers and know the importance of a proper excision in treating malignancy.

However, surgery is not without potential downsides, especially for patients with particular concerns. For example, my typical patient with skin cancer generally is aged 65 years or older, may not have the ability to care properly for their postsurgical wounds or reactions, and may have a comorbidity such as diabetes. These patients also may need a blood thinner or an immunomodulating or immunosuppressive agent for the management of those comorbidities. These factors increase the risk for this patient to have complications following surgical removal of a malignancy, complicating our standard approach to NMSC treatment.

Because of these considerations, I incorporated surface radiotherapy, both electronic brachytherapy (EBT) and superficial radiation therapy (SRT), into my practice. The clinical guidelines for basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC) state radiation therapy can be used for the treatment of NMSCs in special situations in which surgery may be contraindicated or undesired by the patient.1,2 Both SRT and EBT are FDA-approved approaches for select patients with NMSC. In my practice, patients have responded favorably to a number of treatment sites, including the nose and face, scalp, hands, ears, and lower legs. Additionally, I have found that my patients have requested surface radiotherapy during the ongoing pandemic to avoid prolonged face-to-face contact in the office. Generally, these treatments are painless, the sites heal relatively quickly with minimal to no scarring, and these procedures are typically reimbursed by Medicare.

EBT uses low-energy, superficial x-rays in the range of 50 to 70 kV. The lower energy allows for a higher dose per fraction and fewer treatments, usually a series of eight to 12 visits. The surface applicators and a small source-to-skin distance results in a very sharp field edge, thereby smaller margins around the lesion and sparing surrounding healthy tissue. SRT, on the other hand, uses slightly higher voltage, less time on tissue for each treatment, and typically requires 15 to 20 treatments. Treatment is typically delivered twice per week for EBT, where- as SRT is administered 3 times per week. Actual treatment time on tissue is generally 1 to 1.5 minutes, and my patients appreciate that they are in and out of the office in roughly 15 minutes. The current literature indicates a satisfactory cure rate, making surface radiotherapy a sound alternative to surgery.3-6

Herein I share two cases of NMSCs treated with surface radio- therapy as alternative approaches to surgery.

Figure 1.
Figure 1. SCC lesion (A) at initial visit, (B) after four treatments, (C) after seven treatments, (D) on final day of treatment at week 5 showing localized reaction, and (E) 3 months post-treatment.

Case Studies
Case 1. An 84-year-old man presented to my practice with a 1.5- x 1.5-cm SCC located on the right inferior lateral forehead in the temple area. His medical history included cardiac disease, anticoagulation therapy, type 2 diabetes, and multiple previous NMSCs. After discussing both surgery and radiation therapy as potential treatment options, the patient noted he preferred to avoid surgery based on past treatment experiences and chose radiotherapy because of the less invasive nature and listed indications. EBT was selected as the best option to provide a short course of treatment.

Over the course of 5 weeks (Figure 1), 10 total fractions were administered (two fractions/week). The total treated margin was 1.25 cm, treated to surface at 4.0 Gy per fraction (40.0 Gy total target dose). As expected, the radiation caused an acute skin reaction with erythema, crusting, and scaling. This was treated with over-the-counter (OTC) emollients applied daily and occasional use of hydrocortisone 2.5% ointment. Recovery took approximately 6 weeks, and at 3 months posttreatment, the patient was well healed, show- ing little evidence of treatment and no scarring. The patient was happy with the results and painless nature of the treatment process.

Figure 2
Figure 2. BCC lesion at (A) initial visit prior to biopsy, (B) after four treatments, (C) after seven treatments, (D) on final day of treatment showing localized erythema and crusting, and (E) 5 weeks posttreatment.

Case 2. An 80-year-old man presented with a nodular BCC located on the right preauricular area. He had a past medical history of cardiac disease, anticoagulation therapy, and multiple skin cancers. Given the patient’s past medical history, both surgery and radiation therapy were discussed as potential treatment options with the patient. After outlining the options, radiotherapy was chosen due to the less invasive nature and listed indications. As in the previous case, I prescribed EBT. At the initial visit, the BCC measured 1.2 x 0.8 cm (Figure 2). Nine total fractions, with two fractions administered per week, were prescribed at 4.5 Gy per fraction (40.5 Gy total target dose). The BCC was treated to surface at a treatment margin of 0.9 cm. Over the treatment course, the patient experienced an acute reaction with erythema, crusting, and scaling, and he was advised to treat with OTC emollients. At 1 month posttreatment, the skin was well healed with minimal scarring, and the patient was pleased with the outcome.

Conclusion
Given the volume of NMSCs as well as the patient population seen in my practice, this additional therapeutic option has given me another tool for treating malignancy in the office. From the point of view of patients who are apprehensive or fearful of pain or surgical complications, and who otherwise meet the indications for SRT/EBT, surface radiotherapy has become a welcome, less stressful alternative to traditional surgery.

Dr Davis is a board-certified dermatologist and medical director of the Dermatology & Laser Center of San Antonio in Texas. He is also adjunct professor of medicine/dermatology at the UT Health San Antonio Medical School.

References
1. Kim JYS, Kozlow JH, Mittal B, Moyer J, Olenecki T, Rodgers P; Work Group, Invited Reviewers. Guidelines of care for the management of basal cell carcinoma. J Am Acad Dermatol. 2018;78(3):540-559. doi:10.1016/j.jaad.2017.10.006
2. Kim JYS, Kozlow JH, Mittal B, Moyer J, Olenecki T, Rodgers P; Work Group, Invited Reviewers. Guidelines of care for the management of cutaneous squamous cell carcinoma. J Am Acad Dermatol. 2018;78(3):560-578. doi:10.1016/j.jaad.2017.10.007
3. Ballester-Sánchez R, Pons-Llanas O, Candela-Juan C, et al. Two years results of electronic brachytherapy for basal cell carcinoma. J Contemp Brachytherapy. 2017;9(3):251- 255. doi:10.5114/jcb.2017.68191
4. Paravati AJ, Hawkins PG, Martin AN, et al. Clinical and cosmetic outcomes in patients treated with high-dose-rate electronic brachytherapy for nonmelanoma skin cancer. Pract Radiat Oncol. 2015;5(6):e659-e664. doi:10.1016/j.prro.2015.07.002
5. Bhatnagar A. Nonmelanoma skin cancer treated with electronic brachytherapy: results at 1 year. Brachytherapy. 2013;12(2):134-140. doi:10.1016/j.brachy.2012.08.003
6. Shah C, Ouhib Z, Kamrava M, et al. The American Brachytherapy Society consensus statement for skin brachytherapy. Brachytherapy. 2020;19(4):415-426.