Development and internal validation of a clinical-MRI nomogram for predicting lymph node metastasis in rectal adenocarcinoma
Year: 2026
Type: article
Study design: Observational Study
Abstract: Background: Preoperative estimation of lymph node metastasis (LNM) is relevant to treatment planning in rectal adenocarcinoma. We developed and internally validated a clinical-magnetic resonance imaging (MRI) nomogram for LNM prediction using routinely available clinical, laboratory, and MRI features. Methods: This single-center retrospective study included 196 patients with rectal adenocarcinoma, including 72 patients with LNM and 124 patients without LNM. The final multivariable logistic regression model included MRI-based tumor stage (mrT), MRI-based nodal stage (mrN), MRI-detected mesorectal fascia involvement (mrMRF), MRI-detected extramural venous invasion (mrEMVI), age, lymphocyte count, and carcinoembryonic antigen (CEA). Discrimination, calibration, clinical utility, and internal validity were assessed using receiver operating characteristic (ROC) analysis, calibration assessment, decision curve analysis (DCA), and bootstrap validation. Results: The clinical-MRI nomogram showed good discrimination, with an apparent area under the curve (AUC) of approximately 0.815 [95% confidence interval (CI): 0.754-0.874]. The bootstrap-corrected AUC was approximately 0.791. At the Youden-index cutoff of 0.409, sensitivity was 0.694, specificity was 0.790, accuracy was 0.755, positive predictive value was 0.658, and negative predictive value was 0.817. The Hosmer-Lemeshow P value was 0.599. DCA suggested potential net benefit across parts of the displayed threshold range; because no treatment threshold was prespecified, this analysis was considered exploratory. Conclusions: The clinical-MRI nomogram showed good apparent discrimination and acceptable internal validation performance for preoperative LNM prediction in rectal adenocarcinoma. It may support individualized preoperative risk stratification as an adjunctive tool, but it is not intended to replace radiologist interpretation, pathological assessment, or multidisciplinary judgment. Multicenter external validation is required before clinical implementation.
Authors: Yafei Li, Fuquan He, Lei Zhu
Language: English
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7224131219