Major prognostic factors for recurrence and survival independent of the American Joint Committee on Cancer eighth edition staging system in patients with cutaneous squamous cell carcinoma treated with multimodality therapy

Background: The purpose of this study was to assess changes resulting from the American Joint Committee on Cancer (AJCC) eighth edition for cutaneous squamous cell carcinoma (SCC) and evaluate pertinent excluded factors. Methods: In 101 patients receiving surgery and postoperative radiation, recurrence and survival were estimated by cumulative incidence and Kaplan-Meier method. Time-to-event analysis was performed using Cox proportional hazards and Fine-Gray competing risks regression models. Results: The 2-year locoregional recurrence, overall survival (OS), and causespecific mortality rates were 25%, 72%, and 13%, respectively. The AJCC eighth edition upstaged T classification in 50% of patients and overall stage in 39%. In multivariate analysis, immunosuppression and in-transit metastasis were associated with locoregional recurrence. Older age and in-transit metastasis were associated with worse OS. In univariate analysis (limited by number of events), cause-specific mortality was associated with positive margin, in-transit metastasis, and the seventh edition dichotomized T classification and overall stage. Conclusion: In-transit metastasis was significantly associated with locoregional recurrence, OS, and cause-specific mortality. Efforts should be made to define intransit metastasis in the staging system.