Ran, Nina A.

ABSTRACT Background Current staging systems for head and neck cutaneous squamous cell carcinoma (HNCSCC), such as AJCC8 and BWH, often fail to adequately stratify high‐risk patients, particularly due to the exclusion of important biological and host factors. This study aimed to identify independent prognostic factors for HNCSCC outcomes in the largest multi‐institutional retrospective series to date. Methods De‐identified data from 8,610 primary HNCSCC tumors, treated with curative intent surgery across multiple international centers, were analyzed. Outcomes included local recurrence (LR), locoregional metastasis (LM), distant metastasis (DM), and disease‐specific death (DSD). Multivariable Fine–Gray subdistribution hazard regression models with robust standard errors clustered at the patient level were fitted to generate exploratory hypotheses regarding independent hazard determinants. Results During a median follow‐up of 31.4 months (IQR 14.2–52.8), the cumulative incidence was 3.3% for LR, 2.7% for LM, 0.5% for DM, and 1.2% for DSD. Multivariable analysis confirmed that tumor diameter, poor differentiation, deep invasion, and large‐caliber perineural invasion (LCPNI) were the strongest predictors, being significantly associated with at least three of the four outcomes. Notably, factors currently excluded from or weighted differently in staging systems also proved critical: Immunosuppression was significantly associated with LR (SHR 2.03) and DSD (SHR 1.70); and lymphovascular invasion (LVI) was independently associated with LM (SHR 3.00). Poor differentiation demonstrated high prognostic impact, being a significant predictor for all four endpoints. Conclusion Tumor diameter, poor differentiation, deep invasion, LCPNI, immunosuppression status, and LVI are the most critical independent factors for HNCSCC prognosis. Our multi‐institutional data provide a robust framework for hypothesis generation, highlighting that incorporating host biological features and non‐anatomic variables could significantly refine future staging system discussions.

ABSTRACT Importance Risk stratification of cutaneous squamous cell carcinoma (CSCC) is central to effective management. Despite advancements in the 8th edition of the American Joint Committee on Cancer (AJCC8) staging system, the distinctiveness of T‐stages remains limited. Objective To evaluate the effectiveness of the Brigham and Women's Hospital (BWH) and the AJCC8 staging systems in predicting poor outcomes in head and neck (HN) CSCC. Design A retrospective, multinational cohort study of CSCCs diagnosed between January 10, 1991, and December 31, 2023. Setting Twelve centers across the United States (10), Spain (1), and Brazil (1). Participants Patients with invasive CSCC who underwent curative‐intent surgical treatment. Exclusions included cases of lip CSCC, cases with prior HN cancer with associated regional disease, patients with a history of chemotherapy/radiotherapy for other HN neoplasms, and recurrent primary tumors. Exposure Tumors were staged according to both the AJCC8 TNM staging system and the BWH tumor classification. Main Outcomes and Measures Local recurrence (LR), nodal recurrence (NR), distant recurrence (DR), and disease‐specific death (DSD). Results A total of 9852 excised tumors from 3168 patients were included. The 2 systems had comparable monotonicity and homogeneity. Significant differences could be observed in 5‐year cumulative incidence for DSD in both BWH and AJCC8, and also for LR in BWH. Higher T‐stages exhibited similar curves regarding NR and DR for both AJCC8 and BWH staging systems. Overall, we observed high specificity and NPV, low sensitivity and PPV, and moderately high c‐indices for both the BWH and AJCC8 staging systems in predicting the main outcomes for HNCSCC. Conclusion and Relevance Current AJCC8 and BWH staging systems can accurately predict survival in HNCSCC, although there are still important characteristics to be addressed in future staging systems for better stratification according to the other main outcomes.

ImportanceCutaneous squamous cell carcinoma (CSCC) risk stratification is central to management, and physicians rely on tumor staging systems to estimate risk. The Brigham and Women’s Hospital (BWH) T staging system predicts risk based on 4 tumor risk factors (RFs). However, stage is not precisely associated with the number of RFs, as BWH stage T2b includes CSCCs with 2 and 3 RFs.ObjectiveTo determine how RF number is associated with the risk of recurrence, metastasis, and disease-related death.Design, Setting, and ParticipantsThis retrospective multination cohort study of CSCCs diagnosed between October 1, 1991, and July 19, 2023, was conducted at 12 centers in the US (10), Spain (1), and Brazil (1). Invasive CSCCs with confirmed negative margins longer than 14 days were included. Tumors were excluded if they were metastatic at presentation or received adjuvant therapy. Data were analyzed from October 2023 to August 2024.Interventions or ExposuresCSCCs were stratified by the number of the following RFs (0, 1, 2, 3, or 4): a diameter of 2 cm or larger, poorly differentiated histology, tumor extension beyond subcutaneous fat, and large caliber nerve invasion.Main Outcomes and MeasuresFive-year cumulative incidences of local recurrence, nodal metastasis, distant metastasis, and disease-specific death.ResultsA total of 16 844 CSCCs were included (5978 female individuals [35.5%]; median [IQR] age, 73.9 [65.7-81.8] years), with 0 (12 657 [75.1%]), 1 (2892 [17.2%]), 2 (1015 [6.0%]), 3 ( 225 [1.3%]) or 4 (55 [0.3%]) RFs. Median (IQ) follow up time was 33.6 (14.5-60.3) months. For local recurrence, the risk increased as the number of RF increased from 0 (1.7%; 95% CI, 1.5%-2.0%) to 1 (5.0%; 95% CI, 4.1%-5.9%) to 2 (8.8%; 95% CI, 7.0%-11.0%) to 3 (16.0%; 95% CI, 11.0%-22.0%) to 4 (33.0%; 95% CI, 19.0%-47.0%; P < .001 for between-group differences). This increase was also observed for nodal metastasis (0.6% [95% CI, 0.4%-0.7%] vs 3.6% [95% CI, 2.9%-4.4%] vs 11.0% [95% CI, 9.2%-13.0%] vs 20.0% [95% CI, 15.0%-26.0%] vs 28.0% [95% CI, 15.0%-42.0%], respectively; P < .001), distant metastasis (0.2% [95% CI, 0.1%-0.3%] vs 1.1% [95% CI, 0.7%-1.6%] vs 2.3% [95% CI, 1.4%-3.4%] vs 7.9% [95% CI, 4.6%-12.0%] vs 8.4% [95% CI, 2.6%-19.0%], respectively; P < .001), and disease-specific death (0.3% [95% CI, 0.2%-0.4%] vs 1.9% [95% CI, 1.4%-2.7%] vs 5.4% [95% CI, 4.0%-7.0%] vs 11.0% [95% CI, 6.7%-16.0%] vs 25% [95% CI, 12%-39%], respectively; P < .001). CSCCs with 3 RFs had higher cumulative incidences of local recurrence (1.6-fold), nodal metastasis (1.9-fold), distant metastasis (4.3-fold), and disease-specific death (1.9-fold) compared with those with 2 RFs.Conclusions and RelevanceThe results of this cohort study suggest that the number of RFs is an indicator of risk, and among BWH T2b tumors, those with 3 RFs represent a higher risk subset.