Brigham and Women's Hospital tumor classification system for basal cell carcinoma identifies patients with risk of metastasis and death

Abstract

Background: Despite approximately 4400 locally advanced US cases annually, high-stage basal cell carcinoma (BCC) is ill-defined.

Objective: To develop a tumor (T) staging system for BCC that will predict metastasis/death and compare its performance with that of the American Joint Committee on Cancer 8th edition (AJCC8) T-staging system.

Methods: Brigham and Women's Hospital (BWH) T staging was developed from a previously published nested cohort of 488 primary BCCs. Tumors were staged via BWH and AJCC8 T-staging systems, and predictions of metastasis and/or death were compared.

Results: The BWH and AJCC8 T-staging systems both captured all metastases/deaths in high T stages (BWH, T2; AJCC8, T3/T4). BWH T2 included 54% fewer cases ≥2 cm than AJCC8 T3/T4. BWH had a higher specificity (0.92 vs 0.80; P < .001) and positive predictive value (24% vs 11%, P < .001) for identifying cases at risk for metastasis/death, and the C-statistic was superior for BWH (P < .001). The BWH T2 10-year cumulative incidence of metastasis/death was 37% (95% confidence interval, 21%-60%).

Limitations: Two-center cohort.

Conclusions: BWH and AJCC 8 BCC staging both capture all metastases and deaths in the upper stages. However, BWH staging does so in half the number of cases, thus minimizing inappropriate up-staging. The risk of metastasis or death in BWH T2 BCC is sufficient to warrant surveillance for recurrence and clinical trials of adjuvant therapy.

Keywords: basal cell carcinoma; death; metastasis; outcomes; recurrence; risk factors; staging.