While the gold standard for basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) is surgical excision,1,2 this option is not always appropriate as some patients are unable to or unwilling to undergo surgery. Also, lesions located on cosmetically sensitive or difficult-to-treat areas carry increased risk for morbidity with surgery.
For these patients, radiation therapy can be an effective treatment option, as well as an add-on for surgical treatment. The American Society of Radiation Oncology developed guidelines for using radiation therapy to treat patients with BCC or cSCC on the head, neck, trunk, and/or extremities.3
“These guidelines standardize recommendations for the most common clinical scenarios, providing clinical pathways for referral to radiation oncology,” said corresponding author Anna Likhacheva, MD, MPH, with the department of radiation oncology at Sutter Medical Center in Sacramento, CA, in an interview with The Dermatologist. “We hope that the dermatology community will find the guidelines helpful, especially when it comes to defining clinical and pathological characteristics that may necessitate a discussion about the merits of definitive and post-operative radiation therapy,” she added.
Developing the Guidelines
A multidisciplinary team including radiation, medical, and surgical oncologists, dermatopathologists, a radiation oncology resident, a medical physicist, and a dermatologist developed the guidelines.
“The major challenge [for creating these recommendations] was the lack of randomized controlled studies and prospectively collected data in general,” said Dr Likhacheva. The authors mainly relied on retrospective study results and expert opinion due to the lack of newly published, well-controlled randomized trials. For each recommendation, “we used strict criteria for quality grading of the cited evidence and strict definitions for strength of recommendations,” said Dr Likhacheva.
The guidelines do not address the management of mucosal head and neck cSCC, vulvar, penile, or perianal skin carcinomas.
Primary treatment of BCC and cSCC with radiation therapy is recommended for:
- Patients who cannot undergo or decline surgical resection (strength of recommendation: strong; quality of evidence: moderate).
- Lesions on anatomic locations where surgery can compromise function or cosmesis (strength of recommendation: conditional; quality of evidence: moderate).
In addition, the guidelines recommend postoperative radiation therapy for patients with BCC or cSCC with gross perineural spread that is clinically or radiologically apparent (strength of recommendation: strong; quality of evidence: moderate).
Among those with cSCC, postoperative radiation therapy is recommended for:
- Patients that have close or positive margins that cannot be corrected with further surgery (strength of recommendation: strong; quality of evidence: low)
- cSCC in the setting of recurrence after a prior margin-negative resection (strength of recommendation: strong; quality of evidence: moderate)
- T3 or T4 tumors (strength of recommendation: strong; quality of evidence: moderate)
- Desmoplastic or infiltrative tumors in the setting of chronic immunosuppression (strength of recommendation: strong; quality of evidence: moderate)
For BCC, postoperative radiation therapy is recommended for close or positive margins that cannot be corrected with further surgery, in the setting of recurrence after a prior margin-negative resection, and those with locally advanced or neglected tumors involving bone or infiltrating muscle. The strength of these recommendations was conditional, and the quality of evidence was low.
Other recommendations in the guidelines include the use of adjuvant radiation therapy for treating regional nodes and regional disease management, and the use of chemotherapy, biologic, and immunotherapy agents before, during, and after radiotherapy.
Areas for Future Research
“There is conspicuous lack of prospective evidence comparing radiation therapy and surgical management,” said Dr Likhacheva.
The authors encouraged practitioners to enroll patients in trials assessing the efficacy and safety of radiation therapy and for patient outcomes to be collected as part of these clinical trials and prospective registers to strengthen the quality of data. Specific areas identified in the guidelines include standardization of radiation fractionation schemes, defining optimal management of microscopic perineural invasion, management of regional nodal basins, and the role of systemic in neoadjuvant, adjuvant, and concurrent settings.
“We hope that multidisciplinary collaboration between dermatologists and radiation oncologists will ultimately lead to a growing body of level I evidence on these topics,” added Dr Likhacheva.
1. Baum C, Bordeaux JS, Brown M, et al. 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. Alam M, Armstrong A, Baum C, et al. 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. Likhacheva A, Awan M, Barker CA, et al. Definitive and postoperative radiation therapy for basal and squamous cell cancers of the skin: Executive summary of an American Society for Radiation Oncology Clinical Practice Guideline. Pract Radiat Oncol. 2020;10(1):8-20. doi:10.1016/j.prro.2019.10.014