Comparison of tumor staging systems for cutaneous squamous cell carcinoma in patients with chronic lymphocytic leukemia

Background: Patients with chronic lymphocytic leukemia (CLL) are at increased risk for poor outcomes as a result of cutaneous squamous cell carcinoma (CSCC). Objective: To compare the relative effectiveness of tumor staging systems for CSCC in a well-defined cohort of patients with CLL. Methods: This retrospective outcomes study included 454 CSCC tumors among 161 patients with underlying CLL who were evaluated at a single academic medical center. Each tumor was staged according to Brigham and Women's Hospital (BWH), Union for International Cancer Control eighth edition (UICC8), and American Joint Committee on Cancer seventh edition (AJCC7) and eighth edition (AJCC8) criteria. We compared the effectiveness of tumor risk stratification according to each system. Results: The BWH tumor staging system demonstrated superior risk stratification relative to the AJCC7 criteria (C-index, 0.725 vs 0.615; P =.036) and trended toward improved stratification relative to the AJCC8 (C-index, 0.796 vs 0.732; P =.214) and UICC8 (C-index, 0.725 vs 0.636; P =.096) staging systems. Limitations: Our study must be interpreted in the context of its retrospective design and relatively small number of adverse outcomes available for statistical analysis. Conclusions: The BWH system outperformed the AJCC7 criteria and trended toward superior risk stratification relative to both the AJCC8 and UICC8 criteria.