Predicting neoadjuvant chemoradiotherapy response in rectal cancer: Insights from biomarkers to clinical practice

Table 1 Tumor regression grading systems and prognostic value

TRG system	Description	Prognostic value	Limitations
mDworak	Evaluates primary tumor + regional LNs; TRG 4 = ypT0N0, TRG 3 = near-complete regression	Best predictor of RFS and OS (Kim et al[21]); C-statistic: 0.6492 (RFS), 0.6783 (OS)	Requires LN assessment, less commonly used
AJCC	TRG 0-3 scale (complete response to poor response)	Predictive of survival (Kim et al[21]); C-statistic: 0.6359 (RFS), 0.6718 (OS)	Moderate reproducibility
Dworak	TRG 4 = complete regression, TRG 1 = minimal regression	Associated with survival, but lower reproducibility (Chetty et al[27])	Interobserver variability (kappa 0.28-0.35)
Ryan	TRG 0-3 scale; used in multiple cancers	Predictive of recurrence and survival (Kim et al[21])	Similar performance to AJCC and Dworak
Mandard	TRG 1-5; based on fibrosis and residual tumor	Predicts DFS in esophageal cancer (Mandard et al[23])	Lower reproducibility compared to Becker (kappa 0.28)
Becker	TRG 1a-b (< 10% residual tumor) predictive of survival	High reproducibility	Less widely used outside gastric cancer
Rödel	TRG 4 = complete regression	Favorable outcomes in rectal cancer (Rödel et al[26])	Requires histopathological expertise

mDworak: Modified Dworak; LNs: Lymph nodes; TRG: Tumor regression grading; RFS: Recurrence-free survival; OS: Overall survival; AJCC: American Joint Committee on Cancer; DFS: Disease-free survival.