Invasive squamous cell carcinoma of the skin: Defining a high-risk group

Background: Unlike its more common non-invasive form, invasive squamous cell carcinoma (SCC) of the skin can be biologically aggressive and is prone to recur. The objectives of this study were to identify relevant clinicopathologic prognostic factors associated with the outcomes of patients with invasive SCC in order to define a high-risk group. Methods: We retrospectively reviewed the records of patients with invasive cutaneous SCC of the trunk or extremities who received surgical treatment at a tertiary care cancer center over the past 10 years. We examined the patterns of presentation, all known clinical and histological risk factors for recurrence, and their association with survival. Results: 136 patients were identified, of whom 102 (74%) were male. Patterns of presentation included primary (n = 91), locally recurrent (n = 16), regional nodal (n = 24), and distant (n = 5) disease. Univariate analysis identified poorly differentiated carcinomas (hazard ratio [HR] = 2.92, P = .016), scar carcinomas (HR = 3.12, P = .008), tumor size > 2 cm (HR = 3.79, P = .006), and regional nodal disease (HR = 5.77, P < .0001) as significant risk factors for recurrence or death. On multivariate analysis, however, only regional nodal disease at presentation (HR = 7.64, P < .0001) was found to be significant. Conclusions: Patients with invasive SCCs metastatic to regional nodes constitute a group at high risk for recurrence and death. Such patients should be considered for adjuvant therapy trials.