Host and primary tumor factors for the development of multiple cutaneous squamous cell carcinomas among a retrospective cohort in Rhode Island.

INTRODUCTION: Risk factors for a primary cutaneous squamous cell carcinoma (CSCC) are well-established; however, the host and primary tumor risk factors for subsequent CSCC have not been fully explored. METHODS: We performed a retrospective chart review of patients diagnosed with CSCC in an academic dermatology clinic in Rhode Island from 2016-2019. Logistic regression was used to evaluate the associations between host factors and multiple CSCC and between primary tumor characteristics and the risk of subsequent CSCC. Adjusted odds ratios (aORs) and 95% CIs were calculated. RESULTS: A total of 1312 patients with CSCC diagnoses were included. Host risk factors significantly associated with multiple CSCCs included: aged >80 years (aOR, 2.18; 95% CI, 1.46-3.31); history of: solid organ transplant (aOR, 2.41; 95% CI, 1.20-4.80); skin cancer (aOR, 1.96; 95% CI, 1.52-2.54); other cancer (aOR, 1.49; 95% CI, 1.11-2.00); family history of skin cancer (aOR, 1.36; 95% CI, 1.03-1.78); and actinic keratosis (aOR, 1.52; 95% CI, 1.18-1.95). Tumor location, diameter, histologic differentiation, and treatment were not significant predictors of subsequent CSCCs. LIMITATIONS: Study patients were predominantly White and from a single institution, limiting the generalizability of results. CONCLUSIONS: Certain host characteristics were associated with the development of subsequent CSCC, which may inform clinical guidelines for follow-up.