Locally advanced non-melanomatous skin cancer: Contemporary radiotherapeutic management

Non-melanomatous skin cancers (NMSC), comprising both cutaneous squamous cell carcinomas (SCC) and basal cell carcinomas (BCC), are the most common malignancies in fair-skinned persons, frequently arising in the sunexposed head and neck region. Simple surgical excision is usually curative in the majority of low-risk cases, when functional and cosmetic preservation is typically easily achieved. A number of factors portend a more aggressive course in localised lesions, including pathological features such as an involved surgical margin, moderate to poor differentiation, or perineural or lymphovascular invasion, and clinical features including immunosuppression and recurrent cancer status. Though high-level evidence is lacking, consensus guidelines consistently recommend adjuvant radiotherapy in high-risk NMSCs, most commonly in the setting of a positive margin or extensive perineural disease. In non-operative candidates, high-dose radiotherapy can provide long-term control and survival. In SCC, high risk lesions pose an increased risk of regional spread, and consideration should be given to elective nodal treatment, either with neck dissection or irradiation. Development of regional disease, often to the parotid or cervical nodes in the head and neck region, shifts the prognosis substantially and combined therapy consisting of surgery and radiotherapy is then recommended. Limited evidence supports the use of the emerging technologies of protons, heavy particles or stereotactic treatment, but they may be considered in the setting of intracranial perineural spread or the reirradiation setting, when the radiation dosimetry is exceptionally complex. This review aims to provide an update on the current use of radiation in the treatment of locally advanced NMSCs.