Association of SUVmax and never-smoker/never- or minimally-drinker history with PD-L1 expression in resected oral squamous cell carcinoma: a nodal-status-stratified analysis.

BACKGROUND

Programmed death-ligand 1 (PD-L1) is a critical biomarker for immunotherapy selection in oral squamous cell carcinoma (OSCC). However, the relationships between PD-L1 expression and non-invasive indicators, such as metabolic parameters derived from 18F-FDG PET/CT and never-smoker/never- or minimally-drinker (NSND) history, remain poorly defined. Moreover, whether these associations differ across nodal subgroups has not been investigated.

METHODS

This retrospective study included 147 patients with resected OSCC who underwent preoperative PET/CT. Factors associated with high PD-L1 expression (combined positive score [CPS] ≥ 20) were assessed using logistic regression in the overall cohort and with subgroup analyses stratified by nodal status and formal interaction testing.

RESULTS

In the overall cohort, maximum standardized uptake value (SUVmax) (odds ratio [OR] per unit increase = 1.067; 95% confidence interval [CI]: 1.013-1.123; P = 0.014) and gender (OR = 2.254; 95% CI: 1.029-4.936; P = 0.042) were independently associated with high PD-L1 expression. After stratification by nodal status, no clinicopathological or metabolic variable was significantly associated with PD-L1 expression in pN0 patients. In contrast, among pN+ patients, SUVmax (OR per unit increase = 1.113; 95% CI: 1.015-1.222; P = 0.024) and NSND (OR = 4.127; 95% CI: 1.362-12.501; P = 0.012) emerged as independent predictors. The NSND × pN interaction was significant (P = 0.004), whereas the SUVmax × pN interaction was not (P = 0.225).

CONCLUSIONS

SUVmax may serve as a candidate non-invasive indicator, whereas the association between NSND and high PD-L1 expression was modified by nodal status, with a significant effect in node-positive patients. These findings are hypothesis-generating and require external validation.