Identifying Brigham and Women's Hospital stage T2a cutaneous squamous cell carcinomas at risk of poor outcomes

Although most of the poor outcomes with cutaneous squamous cell carcinoma (CSCC) occur in high-stage tumors, 26% of nodal metastases and 8% of disease-specific deaths develop in Brigham and Women's Hospital (BWH) T2a tumors.

To determine risk factors associated with poor outcomes (nodal metastasis, distant metastases, and disease-specific deaths) in BWH T2a CSCC.

A 17-year retrospective multi-institutional cohort study of primary CSCC BWH T2a tumors. A predictive model based on tumor characteristics was developed to identify those at higher risk of poor outcomes.

Presence of 1 major criterion (primary tumor diameter ≥40 mm, invasion depth beyond subcutaneous fat, poor differentiation, or large-caliber perineural invasion) and ≥ 1 minor criterion (invasion depth in subcutaneous fat, moderate differentiation, small-caliber perineural invasion, or lymphovascular invasion) was most predictive of developing poor outcomes (area under the curve, 0.53; C-statistic, 0.60). This model has a sensitivity of 7.7%, specificity of 97.4%, and a positive and negative predictive value of 33.3% and 86.1%, respectively. The 5-year cumulative incidence of poor outcomes in these tumors is 8.0% (95% CI, 5.1-13.7) compared to 2.8% (95% CI, 1.9-4.1) in other T2a tumors (sub-hazard ratio, 3.0; 95% CI, 1.5-5.8).

Multi-institutional cohort study was not externally validated.

BWH T2a-high CSCCs have an 8% chance of developing poor outcomes.