Risk of Distant Metastasis and Oncologic Outcomes of Clinical Near-Complete Responders After Neoadjuvant Therapy in Rectal Cancer: A Meta-Analysis
Patricia Marcolin, Spyridon Papadimatos, Pia Canal Zarate, Harrison Thomas Reeder, Itzel Vidal Sanchez, Evangelos MessarisBACKGROUND:
Watch-and-wait has allowed organ preservation in patients with locally advanced rectal cancer who have a clinical complete response to neoadjuvant therapy. The expansion of non-operative management to patients with a near-complete response raises the question of oncological safety in a nonoperative approach in this subset of patients.
OBJECTIVE:
We aimed to assess the prognostic impact of clinical response after neoadjuvant therapy and to assess the oncologic safety of nonoperative management in patients with near-complete or complete clinical responses.
DATA SOURCES:
We systematically reviewed PubMed, Embase and Web of Science in October 2025 to identify studies comparing oncological outcomes of patients with clinical or near-complete response.
STUDY SELECTION:
Studies comparing clinical response after neoadjuvant therapy in patients with locally advanced rectal cancer were included. We excluded conference abstracts.
MAIN OUTCOME MEASURES:
Primary outcome was overall survival. Secondary outcomes included distant metastasis, local regrowth, local regrowth-free survival, and organ preservation rate.
RESULTS:
We included 10 studies and 1,763 patients. Near-complete response after neoadjuvant therapy for rectal cancer is associated with higher risk of distant metastasis (16.8 vs 7.3%; RR 2.31; 95% CI: 1.63–3.26;
LIMITATIONS:
Heterogeneous definitions of near-complete response and lack of standardized reassessment timing and management.
CONCLUSION:
In contrast to individual studies, we found that near-complete response after neoadjuvant therapy may have an increased risk of distant metastasis compared to patients with a complete clinical response.