Impact of Rosacea on Keratinocyte Skin Cancers: A Prospective Case-Control Study of Basal and Squamous Cell Carcinoma Risk.

Introduction: The full range of cutaneous comorbidities associated with keratinocyte skin cancers remains to be elucidated.

Objectives: We aimed to examine other skin diseases in patients with keratinocyte cancer (KC) and to reveal potential associations between them.

Methods: Included in the study were 200 patients with KC and 200 disease-free controls. To identify any additional concomitant dermatological conditions, all study groups underwent examination by two dermatologists.

Results: In patients with KC, 87.5% were diagnosed with basal cell carcinoma and 13.5% were diagnosed with squamous cell carcinoma. There was no statistically significant difference between the two groups regarding sunscreen use habits (P =0.284). Patients with KC exhibited a significantly elevated odds ratio (OR) for the presence of rosacea (OR 5.13, 95% CI: 3.2-8.3, P=0.000) and especially erythematotelangiectatic rosacea (ETR) subtype (OR 5.03, 95% CI: 3.1-8.2, P=0.000). An Receiver Operating Characteristic (ROC) curve analysis was conducted to assess the efficacy of rosacea in differentiating between the control group and patients with KC. The sensitivity, specificity, negative predictive value, and positive predictive value for rosacea were 45.5%, 86%, 61.2%, and 76.5%, respectively (AUC 0.658, 95% CI: 0.604-0.711, P=0.000), while for ETR it was 44%, 86.5%, 60.7%, and 76.5%, respectively (AUC 0.653, 95% CI: 0.599-0.706, P=0.000). The presence of rosacea demonstrated a significant efficacy in differentiating patients with KC from the control group in all localizations (P< 0.05).

Conclusion: The risk of rosacea in patients with KC, particularly those with the ETR subtype, was found to be significantly elevated, irrespective of age, sex, or localization.