Introduction Neoadjuvant chemoradiotherapy has been shown to reduce local recurrence following radical surgery for rectal cancer with contemporary studies reporting a complete pathological response of up to 30%. Radical surgery is associated with significant morbidity that may be avoided by local excision in selected cases. This systematic review aimed to determine the oncological outcomes of local excision following neoadjuvant therapy.

Method A systematic search of the Medline, EMBASE and Cochrane Library databases was conducted to identify suitable articles. The search strategy captured terms for rectal cancer, neoadjuvant therapy and local excision. Outcomes are presented as weighted pooled proportions where appropriate.

Results A total of 21 unique studies were included (one randomised controlled trial, four comparative cohort studies and 16 cohort studies) that described 1070 patients. The pre-treatment T-stage was cT1 in 2.4%, cT2 in 38.1%, borderline cT2/T3 in 2.7%, cT3 in 37.6%, cT4 in 0.1% and not specified in 19.6% of cases. Long course chemoradiotherapy was administered to 94.0% of patients and short course radiotherapy to 6.0%. Local excision techniques included transanal endoscopic microsurgery (53.7%), transanal excision (34.9%) and other approaches (11.4%). The pooled complete clinical response was 59.4% (95% confidence interval, 43.4% to 74.5%) and the pooled complete mural pathological response (ypT0) was 40.7% (95% CI, 33.6% to 47.9%). The median range of follow up was 38.2 months (range, 12 to 81 months). ypT0 tumours had a pooled local recurrence (LR) of 5.4% (95% CI, 2.8% to 8.7%) and a median disease free survival (DFS) of 90% (70% to 100%). The pooled LR and median DFS for ≥ypT1 tumours was 21.5% (95% CI, 14.8% to 29.0%) and 68.5% (58.3% to 100%), respectively.

Conclusion Patients undergoing local excision with a complete mural pathological response had favourable oncological outcomes compared to those achieved with radical surgery. Given the unacceptably high rate of local recurrence among incomplete responders, future studies should focus on predicting those patients who will achieve a complete response.

Disclosure of interest None Declared.