Radiomics for preoperative pancreatic ductal adenocarcinoma risk stratification: Cross-population validation, multidimensional integration, challenges, and future directions

Table 1 Recurrence rates and median recurrence-free survival by risk stratification

Risk groups (risk score)	Recurrence rates (reader 1)	Recurrence rates (reader 2)	Median recurrence-free survival
Low risk (< 2 points)	39.0%	50.0%	Significantly longer
Intermediate risk (2-4 points)	82.1%	79.5%	Shorter
High risk (≥ 5 points)	84.5%	88.9%	The shortest

Risk scores were calculated based on five computed tomography-derived variables: (1) Tumor size: 0 points for ≤ 2 cm, 1 point for 2-4 cm, 2 points for ≥ 4 cm; (2) Portal venous phase density: 0 points for isodense/hyperdense, 1 point for hypodense; (3) Tumor necrosis: 0 points for absent, 2 points for present; (4) Peripancreatic infiltration: 0 points for absent, 1 point for present; and (5) Suspicious metastatic lymph nodes: 0 points for absent, 2 points for present. Total scores were stratified into low risk (< 2), intermediate risk (2-4), and high risk (≥ 5).