A Word of Caution: Watch and Wait in the Total Mesorectal Excision Era.
Abstract
Background
Watch and wait strategies offer organ preservation for selected patients with rectal cancer following neoadjuvant chemoradiotherapy (nCRT). Long-term outcomes following nCRT and total mesorectal excision (TME) provide important context for evaluating these approaches. We report regional surgical, pathological, and long-term oncological outcomes following nCRT and TME, with oncological outcomes stratified by treatment response.
Methods
A multicentre retrospective cohort study included patients with rectal cancer treated with curative-intent nCRT followed by TME across four Western Australian centres between 2006 and 2020. Overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS) were estimated using Kaplan-Meier methods. Local and metastatic recurrence were estimated using cumulative incidence functions, with death without the recurrence of interest treated as a competing event. Outcomes were stratified by baseline clinical stage, pathological stage, and American Joint Committee on Cancer (AJCC) tumour regression grade (TRG).
Results
Among 573 patients, anastomotic leak occurred in 10.8% of patients with an anastomosis and an intended permanent stoma was formed in 31.9%. A pathological complete response occurred in 21.8%, and 3.1% had a positive circumferential resection margin. Five-year OS was 85.7%, CSS was 89.3% and DFS was 76.7%. The five-year cumulative incidences of local and metastatic recurrence were 3.4% and 16.5%, respectively. Baseline clinical stage was not associated with oncological outcomes, whereas pathological stage and AJCC TRG provided significant prognostic stratification. Five-year DFS was 92.2% for TRG 0% and 62.9% for TRG 3, with corresponding metastatic recurrence of 3.9% and 24.9%.
Conclusion
Long-course nCRT followed by TME achieved favourable long-term oncological outcomes. Pathological stage and AJCC TRG provided greater prognostic stratification than baseline clinical stage. These response-stratified estimates provide regional context for evaluating contemporary organ-preservation programmes.