Association of Coloproctology of Great Britain & Ireland (ACPGBI): Guidelines for the Management of Cancer of the Colon, Rectum and Anus (2017) - Multidisciplinary Management

Adjuvant radiotherapy after local excision of rectal cancer

BACKGROUND

Local excision is now accepted as a standard treatment option for certain patients with early rectal cancer. However, there is a higher risk of local recurrence than after radical surgery with total mesorectal excision. Adjuvant radiotherapy after local excision may reduce this excess risk, and yet retain the benefits of local excision, with rectal preservation.

METHODS

A review of the literature pertaining to the use of adjuvant radiotherapy after local excision of rectal cancer and a discussion of current practice.

RESULTS

We first considered local excision as a treatment option for early rectal cancer, looking at technical developments and the risks and benefits of organ preservation, in particular, the advantages for quality of life and the risk of leaving residual disease which may result in local recurrence. We then looked at reported outcomes for studies using adjuvant radiotherapy after local excision. Few of the studies routinely used modern endoscopic methods of local excision and only the recent used chemoradiation. Local recurrence rates after adjuvant radiotherapy have improved over time, with rates of around 3.5% in the recent studies. Adverse effects of adjuvant radiotherapy are not commonly described, but generally, they are relatively mild when described. We then discussed current practice regarding adjuvant radiotherapy, including pathological criteria, discussion of local recurrence risk with the patient and the importance of a surveillance regime to detect any recurrence at an early stage.

CONCLUSION

We conclude that the current state of knowledge regarding adjuvant radiotherapy after local excision suggests a potential role in decreasing the risk of local recurrence but further studies are required to better define this effect, clarify which patients will gain the most benefit from this pathway, and identify those who should avoid exposure to the risks of radiotherapy.

The 2017 European Society of Coloproctology (ESCP) collaborating group. Evaluating the incidence of pathological complete response in current international rectal cancer practice: the barriers to widespread safe deferral of surgery

INTRODUCTION

The mainstay of management for locally advanced rectal cancer is chemoradiotherapy followed by surgical resection. Following chemoradiotherapy, a complete response may be detected clinically and radiologically (cCR) prior to surgery or pathologically after surgery (pCR). We aim to report the overall complete pathological response (pCR) rate and the reliability of detecting a cCR by conventional pre-operative imaging.

METHODS

A pre-planned analysis of the European Society of Coloproctology (ESCP) 2017 audit was performed. Patients treated by elective rectal resection were included. A pCR was defined as a ypT0 N0 EMVI negative primary tumour; a partial response represented any regression from baseline staging following chemoradiotherapy. The primary endpoint was the pCR rate. The secondary endpoint was agreement between post-treatment MRI restaging (yMRI) and final pathological staging.

RESULTS

Of 2572 patients undergoing rectal cancer surgery in 277 participating centres across 44 countries, 673 (26.2%) underwent chemoradiotherapy and surgery. The pCR rate was 10.3% (67/649), with a partial response in 35.9% (233/649) patients. Comparison of AJCC stage determined by post-treatment yMRI with final pathology showed understaging in 13% (55/429) and overstaging in 34% (148/429). Agreement between yMRI and final pathology for T-stage, N-stage, or AJCC status were each graded as 'fair' only (n = 429, Kappa 0.25, 0.26 and 0.35 respectively).

CONCLUSION

The reported pCR rate of 10% highlights the potential for non-operative management in selected cases. The limited strength of agreement between basic conventional post-chemoradiotherapy imaging assessment techniques and pathology suggest alternative markers of response should be considered, in the context of controlled clinical trials.