Prognostic Factors and the Role of Adjuvant Radiation Therapy in Non-Melanoma Skin Cancer of the Head and Neck

Abstract

Non-melanoma skin cancer (NMSC) is the most common cancer worldwide. Among the two types of NMSC, basal cell carcinoma (BCC) accounts for approximately 75% to 80% of cases and cutaneous squamous cell carcinoma (cSCC) accounts for 20% to 25% of cases. The majority of lesions are low risk and treated with simple surgical excision, which provides histopathologic information and is associated with high cure rates and acceptable cosmetic and functional outcomes. cSCCs are generally more aggressive than BCCs. NMSC commonly occurs in the sun-exposed head and neck region (80% to 90%). Approximately 5% of patients with NMSC (mainly cSCC) will have clinicopathologic features that predict for an increased risk for local and regional recurrence and, rarely, distant relapse. These features include locally advanced primary disease (stage T3-T4), regional nodal involvement, clinical perineural invasion, recurrent disease following treatment, and immunosuppression. Patients who have these features may warrant review by a multidisciplinary tumor board and might require combined modality treatment involving surgery and adjuvant radiation therapy (RT). This article focuses on our current understanding of the prognostic factors and role of adjuvant RT in high-risk NMSC of the head and neck.KEY POINTSNon-melanoma skin cancer (NMSC) is the most common cancer worldwide. Approximately 75% to 80% of cases are basal cell carcinoma and 20% to 25% of cases are cutaneous squamous cell carcinoma.Division into low- and high-risk NMSC is somewhat arbitrary since disease type falls on a continuous spectrum, as data from retrospective series have shown.Approximately 5% of patients with NMSC (mainly cutaneous squamous cell carcinoma) are considered to be at high risk for relapse, either local, regional, or distant (rarely), following surgery.Because of the dearth of high-level evidence on the benefits of adjuvant radiation therapy (RT), there is a lack of universally adopted guidelines regarding its use. Use of adjuvant RT is commonly based on individual institutional policy.Retrospective series support consideration of adjuvant RT in the presence of advanced primary disease (stages T3-T4), regional nodal involvement, clinical perineural invasion (cPNI) and immunosuppression.