ΔAverage of long and short axis diameter on non-contrast CT is associated with major pathological response to neoadjuvant immunotherapy in resectable non-small cell lung cancer.

objectiveNeoadjuvant immunotherapy for non-small cell lung cancer shows heterogeneous efficacy, and Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) fails to accurately predict pathological response. The objective was to explore computed tomography parameters associated with neoadjuvant immunotherapy efficacy and compare their performance with RECIST 1.1. MATERIALS AND

methodsThis multicenter retrospective study included 48 patients with resectable stage I-IIIB non-small cell lung cancer who received neoadjuvant immunotherapy between September 2018 and July 2023. Computed tomography density parameters (computed tomography value and relative computed tomography value) and morphological characteristics (mean diameter, volume, surface area) were measured before and after treatment. Major pathological response (≤ 10% residual tumor cells) served as the reference standard. Receiver operating characteristic analysis and logistic regression evaluated parameter performance.

resultsΔMean diameter demonstrated the highest predictive accuracy for major pathological response (area under the curve 0.83, p < 0.001), with 76% sensitivity, 84% specificity, and 79.2% overall accuracy, with numerically higher accuracy than Response Evaluation Criteria in Solid Tumors version 1.1 (72.9%), though no formal statistical test for superiority was conducted. In exploratory multivariable analysis, it was the only parameter retaining independent association with major pathological response (odds ratio 11.91, 95% confidence interval 1.52-93.11, p = 0.018).

conclusionΔMean diameter is a promising imaging biomarker for predicting pathological response to neoadjuvant immunotherapy. In this cohort, it showed numerically higher accuracy than RECIST 1.1; however, these findings are hypothesis-generating and require both internal and external validation before clinical implementation. KEY POINTS: Question Neoadjuvant immunotherapy for resectable non-small cell lung cancer shows heterogeneous efficacy, and RECIST 1.1 fails to predict major pathological response, requiring reliable biomarkers. Findings ΔMean diameter was associated with major pathological response (AUC = 0.83), showed numerically higher accuracy than RECIST 1.1, and represented an exploratory independent predictor. Clinical relevance This simple computed tomography parameter shows promise for identifying treatment efficacy in non-complete responders, aids personalized therapy decisions, and improves the accuracy of immunotherapy evaluation without complex radiomics or costly positron emission tomography.