Avoiding radical surgery after pre-operative chemoradiotherapy: a possible therapeutic option in rectal cancer?

In this modern era of multi-modality treatment there is increasing interest in the possibility of avoiding radical surgery in complete responders after neo-adjuvant long-course chemoradiotherapy (LCPRT). In this article, we present a systematic review of such treatments and discuss their therapeutic applicability for the future.

We searched the PubMed online libraries to identify studies that reported on the long-term surgical and pathological outcomes after local excision together with those that explored the possibility of clinical observation only in patients achieving a complete clinical response after LCPRT.

Several retrospective (n = 10), one single-arm prospective, and one small randomised series have reported on the use of local excision after LCPRT and demonstrated acceptably low levels of local recurrence with survival comparable to patients progressing to conventional surgery. One prospective series allocated patients to observation or radical surgery based on histological parameters after local excision (ypT0 and ypT1) and showed no differences in outcomes. Two retrospective series from the same group on a Brazilian cohort of patients reported excellent long-term outcomes after "wait and watch" in complete clinical responders. However, other reports have shown no direct correlation between clinical and pathological response.

Local excision may be an appropriate option for selected patients developing good clinical response after LCPRT. In our opinion, a policy of clinical observation in complete clinical responders after LCPRT may not be a safe strategy, unless we had robust predictive models for accurate identification of pathological complete response. In order to identify patients that may be potentially appropriate for such an approach we propose a clinical algorithm incorporating important clinical, radiological, and pathological parameters. The proposed model will require validation in a prospective study. Finally, we need randomised data for demonstrating the non-inferiority of clinical observation compared to conventional surgery before this can be considered as standard possible therapeutic option.