Mucinous rectal adenocarcinoma and neoadjuvant therapy: Implications for surgical practice

Table 1 Evidence on the neoadjuvant response in mucinous rectal adenocarcinoma

Ref.	Design	Population	Key findings
Huang et al[3], 2021	Meta-analysis (15 studies)	> 9000 patients	MAC associated with OR 0.38 for pCR and 0.31 for tumor downstaging vs non-MAC
Zhang et al[18], 2021	Pooled analysis of 3 prospective trials	743 patients (8.5% MAC)	pCR: 7.5% in MAC vs 22.0% non-MAC; yp stage 0-I: 20.8% vs 48.7%; DFS 3-year: 58.4% vs 77.6%
McCawley et al[23], 2016	Meta-analysis	Multiple datasets	Higher CRM positivity (OR 5.02) and mortality (OR 1.53) in MAC
Yu et al[56], 2014	MRI-based prognostic study	Retrospective cohort	Poor radiologic regression; acellular mucin mimics residual tumor on MRI

Summary of key studies evaluating the pathological complete response (pCR), tumor downstaging, margin status, and imaging findings in mucinous adenocarcinoma (MAC) compared with non-MAC. Data highlighted consistent reductions in pCR and downstaging rates for MAC, higher rates of circumferential resection margin (CRM) involvement, and challenges in radiologic assessment due to acellular mucin mimicking residual tumor. DFS: Disease-free survival; MRI: Magnetic resonance imaging; OR: Odd ratio.