Identification of a high risk cutaneous squamous cell carcinoma tumor subset worthy of inclusion in national tumor registries

Introduction: Cutaneous squamous cell carcinoma (CSCC) is the second most common type of skin cancer with deaths estimated to exceed deaths from melanoma in central and southern US. However, CSCC has been excluded from national cancer registries due to its high incidence and subsequent high cost of surveillance; hence population based incidence and outcome studies are unavailable. Methods: Primary CSCCs diagnosed from 2000-2009 (n=1,818) were assigned the 2010 American Joint Committee on Cancer (AJCC) and the 2013 Brigham and Women's Hospital (BWH) tumor (T) stages. Life tables of poor outcomes (local recurrence [LR], nodal metastasis [NM], and disease specific death [DSD]) were constructed and analyzed. Results: Poor outcomes in AJCC were clustered in T2 (72% of LR, 82% of NM, 67% of DSD). In BWH staging, only 6% of CSCCs were in the upper 2 stages (T2b and T3) but they accounted for 53% of LR, 76% of NM, and 83% of DSD. While ten year incidences of LR, NM, and DSD were low for low stage tumors (BWH T1/T2a: 1.3%, 0.5%, and 0.2% respectively), they were significantly higher for high-stage tumors (BWH T2b/T3: 23%, 23%, and 14% respectively). Conclusion: High stage CSCC accounts for the majority of poor outcomes. National surveillance efforts in select geographic regions with outcome tracking focused on the 6% of CSCC tumors that are high-risk (BWH T2b/T3) would allow for cost effective estimation of the impact of this common disease in the US.