Relevance of the primary lesion in the prognosis of metastatic cutaneous squamous cell carcinoma

Background It remains unclear how primary tumor factors impact on prognosis in patients with nodal metastasis in head and neck cutaneous squamous cell carcinoma (SCC). The purpose of this study was to assess whether primary tumor characteristics are independent prognostic factors. Methods Patients treated for metastatic cutaneous SCC from 1978 to 2010 were identified (n = 239). A proportional hazards model was used to assess the effect of primary tumor variables. Results On multivariable analysis, tumor differentiation (hazard ratio [HR], 0.2; 95% confidence interval [CI], 0.1-0.8; p =.03) was found to be significantly associated with disease-specific survival (DSS), unlike margin status (p =.23), tumor size (p =.21), and thickness (p =.11). Patient, treatment, and nodal factors were confirmed to be important predictors of survival. Conclusion This article suggests that pathological features of the primary lesion bear little importance in the presence of established nodal metastasis, other than tumor differentiation. It validates the grouping of T1-3N1 as stage III under the current American Joint Committee on Cancer (AJCC) TNM staging system.