Complete Response after Chemoradiotherapy in Rectal Cancer (Watch-and-Wait): Have we Cracked the Code?

Patients with locally advanced rectal cancer receive preoperative chemoradiation as the standard of care, producing a pathological complete response in 10-20% and a complete clinical response (CCR) in 20-30%. Small observational studies suggest a selective non-operative management with rigorous surveillance is an option and is increasingly being advocated in many parts of the world for patients who achieve a CCR or near CCR. The assumption is that oncological outcomes for good responders, who are observed, compare favourably with patients subjected to radical surgery. Late regrowth of the primary is rare, almost invariably endoluminal and, hence, can be salvaged. However, concerns remain among some surgeons and oncologists regarding the reproducibility of published results in routine practice. We have previously reviewed this topic. The aim of this brief overview was to re-assess the feasibility and safety of a non-operative approach based on the currently available literature. We make recommendations as to the quality of care required to undertake this management. Significant heterogeneity remains in the initial inclusion criteria, staging and restaging methods, study design, timing of assessment, duration and rigour of follow-up of the trials reviewed - all of which obscure the validity of the results.