Regional disease in head and neck cutaneous squamous cell carcinoma: the role of primary tumor characteristics and number of nodal metastases

Purpose: To identify potential risk factors impacting on overall survival (OS) of patients affected by lymph node metastasis from cutaneous squamous cell carcinoma (cSCC) of the head and neck (HN), with special emphasis on primary tumor characteristics and pattern of nodal recurrence (intraparotid and/or cervical). Methods: A bi-institutional retrospective study on consecutive patients affected by cervical and/or intraparotid NM from HN cSCC and surgically treated with curative intent from May 2010 to January 2020 was conducted. OS was considered the outcome of interest. Results: The study included 89 patients (M:F = 3.4:1; median age, 78 years; range, 22–99). Among the primary tumor characteristics, the most relevant prognostic factors were diameter ≥ 4 cm (hazard ratio [HR] = 2.56, p = 0.010) and depth of infiltration ≥ 6 mm (HR = 3.54, p = 0.027). Cervical NM was associated with worse OS (HR = 2.09, p = 0.016) compared to purely intraparotid NM (5-year OS: 60.9% vs. 28.1%, p = 0.014). At multivariable analysis, age, immunosuppression, pT3-T4 categories and a high burden of nodal disease (> 2 NM) confirmed to be independent risk factors, whereas adjuvant radiotherapy was independently associated with better outcome. Conclusion: This study confirms the association of several independent prognosticators related to the patient, primary tumor, and nodal burden status. Patients with cervical NM should be considered at risk for harboring a higher number of metastatic lymph nodes.