The recommendations defined when and how radiation therapy should be used to treat patients with basal cell carcinoma and cutaneous squamous cell carcinoma.The American Society for Radiation Oncology (ASTRO) compiled available evidence to define practice guidelines for the most common clinical situations in using radiation therapy to treat basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC).1
Specific areas of interest identified were standardization of radiation fractionation schemes, defining optimal management of microscopic perineural invasion, management of regional nodal basins, and the role of systemic therapy in neoadjuvant, adjuvant, and concurrent settings.
“For this guideline, we drew on the consensus of a multidisciplinary group of leading experts, as well as a systematic review of the evidence, to help physicians understand when radiation is most likely to benefit their patients and to encourage informed discussion about treatment options,” Anna Likhacheva, MD, MPH, vice chair of the guideline task force and radiation oncologist with Sutter Medical Group, said in a press release.2
In the definitive/curative setting, researchers indicated that radiation is strongly recommended for patients with BCC or cSCC who cannot undergo or decline surgical resection. Conditionally, it is recommended for patients with BCC or cSCC located in anatomically sensitive areas, such as the nose or lips, as surgery could compromise function or cosmetic outcomes. However, definitive radiation therapy is discouraged for patients with genetic conditions that predispose them to be more sensitive to radiation.
For patients with BCC or cSCC that has spread to regional lymph nodes, surgical removal of the affected lymph nodes followed by radiation is strongly recommended, although not for patients with 1 small lymph node involved without extracapsular spread. Research also suggested definitive radiation for patients with regional cSCC spread who cannot undergo surgery.
In the adjuvant/post-operative setting, radiation following surgery is recommended for patients who have a high-risk of cancer recurrence. Radiation is strongly recommended when there is evidence of BCC or cSCC that has spread to the patient’s nerves. Post-operative radiation is recommended for patients with a high risk of recurrence following surgical resection. There are strong recommendations for high-risk patients with cSCC and conditional recommendations for high-risk patients with BCC. The recommendations also outlined the prognostic features that indicate which patients are at greater risk for recurrence and spread.
The guideline also addressed technical aspects of radiation therapy, and suggested dosing, and fractionation schedules, including a description of the different types of radiation delivery methods. Researchers concluded that the appropriate use of any of the major radiation approaches results in similar cancer control and cosmetic outcomes. Also considered in the guideline are the use of drug therapies such as chemotherapy, biologic, and immunotherapy agents in combination with radiation therapy.
Whenever possible, patient outcomes should be collected as part of clinicals trials and prospective registries to bolster the overall quality of data on this topic, according to the researchers.
“We would be highly supportive of population health research looking into practice patterns before and after release of these guidelines, as well as patient outcomes according to treatments offered,” Likhacheva said. “We plan to update the guidelines as new evidence emerges to support changes in the recommendations.”
A task force was assembled by ASTRO to create the comprehensive guideline. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.
According to ASTRO, skin cancer is the most prevalent cancer in the U.S. with more than 5 million cases diagnosed each year, and more than 95% of these diagnoses are BCC or cSCC. Surgery is considered the primary treatment approach, though radiation therapy can play a role in both curative and post-operative treatment.
1. Likhacheva A, Awan M, Barker CA, et al. Definitive and Postoperative Radiation Therapy for Basal and Squamous Cell Cancer of the Skin: Executive Summary of an American Society for Radiation Oncology Clinical Practice Guideline. Practical Radiation Oncology. doi:10.106/j.prro.2019.10.014.
2. ASTRO issues new clinical guideline on radiation therapy for basal and squamous cell skin cancers [news release]. Arlington, VA. Published December 10, 2019. astro.org/News-and-Publications/News-and-Media-Center/News-Releases/2019/ASTRO-issues-new-clinical-guideline-on-radiation-t. Accessed December 10, 2019.