The review, led by Jason G. Newman, MD, director of head and neck surgery at Penn Medicine, Philadelphia, includes evidence-based research findings from the last 10 years which describe the possible roles for adjuvant radiation, chemotherapy, immunotherapy, and/or targeted therapy in the management of high-risk cSCC.
Dr. Newman and colleagues wrote that more data – and high-quality data – are needed for physicians to determine with more confidence which adjuvant therapies would be best for specific patients with high-risk cSCC. But without that data, uncertainty in treatment decisions will persist.
“The requirements for and efficacy of adjuvant therapies in cutaneous squamous cell carcinoma are unclear, and the gap in evidence for practice decisions regarding adjuvant therapy in patients with high-risk cSCC has been apparent for more than a decade,” they wrote.
While surgical excision with clear margins of the primary cSCC lesion remains the standard of care, certain high-risk factors necessitate adjuvant therapy, the authors wrote. However, since the evidence consists of small retrospective studies with conflicting results, it is unclear which patients might benefit from adjuvant therapy. This review included recent and current trials in cutaneous SCC and the role of immune checkpoint inhibitors.
According to the review, adjuvant radiation therapy is usually considered with high-risk features, such as perineural invasion, lymph node metastasis and extracapsular/extranodal extension, if the patient is otherwise at high risk for metastasis or recurrence, or if further surgery is not possible.
The National Comprehensive Cancer Network, the American College of Radiology, and the American Society for Radiation Oncology do not recommend adjuvant radiation therapy for most patients with cSCC. However, adjuvant radiation therapy with or without systemic therapy may be considered in locally advanced disease, when further surgery is not an option, or if there is regional lymph node metastasis, but multidisciplinary consultation is recommended.
Regarding checkpoint inhibitors, the NCCN, ACR, and ASTRO do not recommend the use of systemic therapy for local disease amenable to surgery. Potential use of a checkpoint inhibitor with radiation therapy in a clinical trial is recommended for residual disease in locally advanced cSCC as palliative care when other options are not available. While the use of cemiplimab or pembrolizumab are preferred in regional recurrence when curative surgery and radiation therapy are not an option, a targeted therapy can be considered if this is not feasible.
“Given the current activity of checkpoint inhibition in this disease, enthusiasm for the addition of cytotoxic chemotherapeutic agents in the adjuvant setting may be on the decline,” the authors wrote. “Multidisciplinary approaches will most likely continue to be recommended in complicated cases, including those involving immunosuppression.”
The authors said that further study is needed on prognostic testing, such as gene expression profile testing or sentinel lymph node biopsy, as such testing early in disease could identify patients who would likely benefit from adjuvant therapy. They added that the need to identify patients at early stages of disease who are at high risk for metastasis continues to remain critical.