A Systematic Review of Local Excision After Neoadjuvant Therapy for Rectal Cancer: Are ypT0 Tumors the Limit?

BACKGROUND: Neoadjuvant therapy reduces local recurrence after radical surgery for rectal cancer with complete pathological response in 15% to 25% of patients. Radical surgery is associated with significant morbidity that may be avoided by local excision in selected cases. OBJECTIVE: This systematic review aimed to determine the oncological outcomes and morbidity of local excision after neoadjuvant therapy. DATA SOURCES: Data sources included MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials databases. STUDY SELECTION: A systematic search of the databases using validated terms for rectal cancer, neoadjuvant therapy, and local excision was conducted. INTERVENTIONS: Neoadjuvant therapy and local excision were the included interventions. MAIN OUTCOME MEASURES: Pooled local recurrence, median survival, and pooled morbidity were measured. RESULTS: Twenty unique studies were included (14 cohort, 5 comparative cohort, and 1 randomized controlled trial), describing 1068 patients. Patient choice, prohibitive comorbidity, good clinical response, and early stage disease were the most frequent indications for local excision. Pretreatment T2 and T3 tumors accounted for 46.4% and 30.7% of cases. Long-course treatment was administered in all of the studies, except to a cohort of 64 patients who received short-course radiotherapy. Pooled complete clinical response was 45.8% (95% CI, 31.4%-60.5%), and pooled complete pathological response was 44.2% (95% CI, 36.4%-52.0%). Median follow-up was 54 months (range, 12-81 months). ypT0 tumors had a pooled local recurrence rate of 4.0% (95% CI, 1.9%-6.9%) and a median disease-free survival rate of 95.0% (95% CI, 87.4%-100%). Pooled local recurrence and median disease-free survival rates for ypT1 tumors or higher were 21.9% (95% CI, 15.9%-28.5%) and 68.0% (58.3%-69.0%). Pooled incidence of complications was 23.2% (95% CI, 15.7%-31.7%), with suture-line dehiscence reported in 9.9% (95% CI, 4.8%-16.7%). LIMITATIONS: Limitations included study quality, high risk of selection bias and detection bias in study designs, and limited sample sizes. CONCLUSIONS: Local excision after neoadjuvant therapy should only be considered a curative treatment if complete pathological response is obtained. Given the high rate of local recurrence among incomplete responders, future studies should focus on predicting patients who will achieve complete pathological response.