Validation of the 2022 National Comprehensive Cancer Network Risk Stratification for Cutaneous Squamous Cell Carcinoma.

Importance: The 2022 National Comprehensive Cancer Network (NCCN) reclassified cutaneous squamous cell carcinoma (CSCC) into low-, high-, and very high-risk groups to better risk stratify tumors. Mohs micrographic surgery (Mohs) or peripheral and deep en face margin assessment (PDEMA) became preferred surgical modalities for high- and very high-risk tumors. This new risk stratification and the recommendation for Mohs or PDEMA in high- and very high-risk groups have not been validated.

Objective: To compare outcomes in very high-, high-, and low-risk NCCN groups of CSCCs and in CSCCs treated with Mohs or PDEMA compared with wide local excision (WLE).

Design, Setting, And Participants: This retrospective cohort study of CSCCs was performed in 2 tertiary care academic medical centers. Patients 18 years or older and diagnosed between January 1, 1996, and December 31, 2019, at Brigham and Women's Hospital and Cleveland Clinic Foundation were included. Data were analyzed from October 20, 2021, to March 29, 2023.

Exposures: NCCN risk group, Mohs or PDEMA, and WLE.

Main Outcomes And Measures: Local recurrence (LR), nodal metastasis (NM), distant metastasis (DM), and disease-specific death (DSD).

Results: A total of 10 196 tumors from 8727 patients were stratified by NCCN guidelines into low-, high-, and very high-risk groups (6003 [59.0%] men; mean [SD] age, 72.4 [11.8] years). Compared with the low-risk group, the high- and very high-risk groups demonstrated a greater risk of LR (high-risk subhazard ratio [SHR], 1.99 [95% CI, 1.21-3.27; P = .007]; very high-risk SHR, 12.66 [95% CI, 7.86-20.39; P < .001]), NM (high-risk SHR, 4.26 [95% CI, 1.28-14.23; P = .02]; very high-risk SHR, 62.98 [95% CI, 19.24-206.17; P < .001]), DM (high-risk SHR, 2.2 × 107 [95% CI, 4.7 × 103-1.1 × 1011; P < .001]; very high-risk SHR, 6.3 × 108 [95% CI, 1.4 × 105-2.9 × 1012; P < .001]), and DSD (high-risk SHR, 4.02 [95% CI, 1.18-13.71; P = .03]; very high-risk SHR, 93.87 [95% CI, 29.19-301.85; P < .001]). Adjusted 5-year cumulative incidence was significantly higher in very high- vs high- and low-risk groups for LR (9.4% [95% CI, 9.2%-14.0%] vs 1.5% [95% CI, 1.4%-2.1%] and 0.8% [95% CI, 0.5%-1.2%], respectively), NM (7.3% [95% CI, 6.8%-10.9%] vs 0.5% [95% CI, 0.4%-0.8%] and 0.1% [95% CI, 0.03%-0.3%], respectively), DM (3.9% [95% CI, 2.6%-5.6%] vs 0.1% [95% CI, 0.04%-0.2%] and 0.01% [95% CI, not applicable], respectively), and DSD (10.5% [95% CI, 10.3%-15.4%] vs 0.5% [95% CI, 0.4%-0.8%] and 0.1% [95% CI, 0.04%-0.3%], respectively). Compared with CSCCs treated with WLE, those treated with Mohs or PDEMA had lower risk of LR (SHR, 0.65 [95% CI, 0.46-0.90]; P = .009), DM (SHR, 0.38 [95% CI, 0.18-0.83]; P = .02), and DSD (SHR, 0.55 [95% CI, 0.36-0.84]; P = .006).

Conclusions And Relevance: The findings of this cohort study suggest that the NCCN high- and very high-risk groups identify CSCCs at greatest risk for developing poor outcomes. Further, Mohs or PDEMA resulted in lower LR, DM, and DSD compared with WLE.