452O - Results of a prospective randomised control 6 vs 12 trial: Is greater tumour downstaging observed on post treatment MRI if surgery is delayed to 12...

Date 09 October 2016
Event ESMO 2016 Congress
Session Gastrointestinal tumours, colorectal 1
Topics Colon Cancer
Rectal Cancer
Imaging, Diagnosis and Staging
Surgery and/or Radiotherapy of Cancer
Presenter Jemma Bhoday
Citation Annals of Oncology (2016) 27 (6): 149-206. 10.1093/annonc/mdw370
Authors J. Evans1, J. Bhoday2, B. Sizer3, P. Tekkis4, R. Swift5, R. Perez6, D. Tait1, G. Brown1
  • 1Colorectal Surgery, Royal Marsden Hospital NHS Foundation Trust, SM2 5PT - London/GB
  • 2Colorectal Surgery And Radiology, Royal Marsden Hospital NHS Foundation Trust, SM2 5PT - London/GB
  • 3Colorectal Surgery, Colchester Hospital University Essex County Hospital, CO4 5JL - Colchester/GB
  • 4Colorectal Surgery, Royal Marsden Hospital NHS Foundation Trust, SW3 6JJ - London/GB
  • 5Colorectal Surgery, Croydon University Hospital, CR7 7YE - London/GB
  • 6Colorectal Surgery, Ludwig Institute for Cancer research, 04001-005 - São Paulo/BR

Abstract

Background

The optimum interval between CRT and surgery for locally advanced rectal cancer remains controversial. If greater downstaging occurs with a longer interval to surgery, this may impact on rates of sphincter preservation and survival. A prospective, randomised, multicentre trial was undertaken to determine whether greater rectal cancer downstaging and regression occurs when surgery is delayed to 12 compared to 6-weeks.

Methods

The primary endpoint was difference in proportion of patients in each arm downstaged according to MRI T-stage - defined as any reduction in T-stage/sub-stage. A sample size of 218 patients was required. Secondary endpoints included pCR and mrTRG 1-2 rates.

Results

A total of 237 patients were randomised: 122 (51%) into the 6-week and 115 (49%) to the 12-week arm. A significantly greater proportion downstaged in the 12-week (58%) compared with 43% in the 6-week arm (p = 0.019). The pCR rate was 9% in the 6-week versus 20% for the 12-week arm (p 

Conclusions

Waiting 12-weeks after CRT results in significantly more mrT downstaging, pCR and improved mrTRG. Since mrTRG is a validated predictor of disease free survival, undertaking surgery before maximal regression may be disadvantageous.

Clinical trial identification

Legal entity responsible for the study

N/A

Funding

Biomedical Research Centre

Disclosure

All authors have declared no conflicts of interest.