Evaluation of the Definitions of “High-Risk” Cutaneous Squamous Cell Carcinoma Using the American Joint Committee on Cancer Staging Criteria and National Comprehensive Cancer Network Guidelines

Recent guidelines from the American Joint Committee on Cancer (AJCC) and National Comprehensive Cancer Network (NCCN) have been proposed for the assessment of “high-risk” cutaneous squamous cell carcinomas (cSCCs). Though different in perspective, both guidelines share the common goals of trying to identify “high-risk” cSCCs and improving patient outcomes. Thus, in theory, both definitions should identify a similar proportion of “high-risk” tumors. We sought to evaluate the AJCC and NCCN definitions of “high-risk” cSCCs and to assess their concordance. Methods. A retrospective review of head and neck cSCCs seen by an academic dermatology department from July 2010 to November 2011 was performed. Results. By AJCC criteria, most tumors ( %) were of Stage 1; 46 tumors (13.9%) were of Stage 2. Almost all were of Stage 2 due to size alone (≥2？cm); one tumor was “upstaged” due to “high-risk features.” Using the NCCN taxonomy, 231 (87%) of tumors were “high-risk.” Discussion. This analysis demonstrates discordance between AJCC and NCCN definitions of “high-risk” cSCC. Few cSCCs are of Stage 2 by AJCC criteria, while most are “high-risk” by the NCCN guidelines. While the current guidelines represent significant progress, further studies are needed to generate a unified definition of “high-risk” cSCC to optimize management. 1. Introduction Though it is a rare occurrence, it is well known that prognosis is grim once a cutaneous squamous cell carcinoma (cSCC) has metastasized beyond the skin [1–3]. It would be desirable to be able to identify this small cohort of tumors that are increased risk for metastasis earlier in their presentation to alter treatment approaches and potentially improve outcomes. Recent guidelines from the American Joint Committee on Cancer (AJCC) and National Comprehensive Cancer Network (NCCN) have been proposed to help in the assessment and classification of these “high-risk” cSCCs [4, 5]. Though different in perspective, both guidelines share the common goals of trying to distinguish “high-risk” cSCCs from the bulk of tumors (which are low risk) and trying to optimize patient care. Thus, in theory, both definitions should identify a similar proportion of “high-risk” tumors. In clinical practice, we observed some incongruities between the two definitions. We sought to evaluate the AJCC and NCCN definitions of “high-risk” cSCCs and to assess their concordance. 2. Methods A retrospective chart review of all cSCCs on the head and neck that were initially seen in the Dermatology Department at Saint Louis University Medical Center in July