Association of Serum SCC-Ag With Baseline Disease Extent in Oral and Laryngeal SCC: Exploratory Cross-Sectional Study

Aims To compare serum squamous cell carcinoma antigen (SCC-Ag) levels between Syrian patients with oral or laryngeal squamous cell carcinoma (SCC) and healthy controls and examine their association with baseline clinicopathological characteristics. Methods This analytical cross-sectional study included 60 treatment-naïve patients with histologically confirmed oral or laryngeal SCC and 30 healthy controls. Serum SCC-Ag levels were measured using an enzyme-linked immunosorbent assay. Differences in SCC-Ag levels according to clinicopathological characteristics were assessed using non-parametric tests. Receiver operating characteristic (ROC) analysis assessed apparent discrimination between patients with SCC and healthy controls. Exploratory multivariable logistic regression models examined associations between SCC-Ag and advanced clinical stage or nodal metastasis after adjustment for age, sex, smoking status, and tumour site. Results Median SCC-Ag levels were higher in patients with SCC than in healthy controls (1.450 vs 0.914 ng/mL; P < .001). Median levels were 1.508 ng/mL in oral SCC and 1.203 ng/mL in laryngeal SCC. The apparent AUC for all SCC cases versus healthy controls was 0.849 (95% CI, 0.754-0.931), with an exploratory Youden-derived cutoff of 1.13 ng/mL yielding 86.7% sensitivity and 70.0% specificity. The optimism-corrected AUC after 2,000 stratified bootstrap resamples was 0.848. Higher SCC-Ag levels were associated with advanced T category, nodal metastasis, distant metastasis, and advanced clinical stage. In exploratory adjusted models, SCC-Ag was associated with advanced clinical stage (adjusted OR, 2.08 per 0.1 ng/mL increase; 95% CI, 1.41-3.07; P < .001) and nodal metastasis (adjusted OR, 1.19; 95% CI, 1.03-1.38; P = .017). Conclusion Serum SCC-Ag levels were higher in patients with oral or laryngeal SCC and were associated with baseline disease extent. These preliminary findings support further investigation of SCC-Ag as an adjunct biomarker of disease burden. However, the apparent ROC performance and exploratory associations do not establish diagnostic or prognostic utility in routine clinical practice.