P-331 - Organ sparing radiotherapy in rectal cancer: definitive chemoradiation is a safe and valid option

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Anti-Cancer Agents & Biologic Therapy
Rectal Cancer
Surgery and/or Radiotherapy of Cancer
Presenter R. Brooker
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors R. Brooker, M. McKay, A. Crabtree, H. Wong, R. Sripadam
  • Clatterbridge Cancer Centre, Wirral/UK

Abstract

Introduction

Neoadjuvant chemoradiation (NACRT) is recommended when treating locally advanced rectal cancer to improve likelihood of complete resection. In patients achieving pathological complete response (pCR) after NACRT and surgery, reduced loco-regional recurrence rates have been observed. Extrapolating from this, patients (with low rectal cancers) achieving clinical CR (cCR) after NACRT can be entered into a close surveillance protocol instead of having a major operation (APR) and permanent stoma (1). We retrospectively and prospectively analysed the clinical course of such a series of patients for outcomes. Our primary endpoint was progression free survival.

Methods

Patients with clinical/radiological (cCR) and/or negative random biopsies at endoscopy following NACRT were identified via clinical records spanning the dates October 2009 and January 2013. Survival was calculated using IBM-SPSS Statistics version 19.

Results

21 patients (with low rectal cancers) had cCR post NACRT after random biopsies or follow up MRI. All were PS 0-2 and had mean age 69 years. 72%(15) had stage 3a/3b disease, the remainder stage 1-2 and circumferential resection margin was involved in 15%(3). 95%(20) were adenocarcinomas.

Radiotherapy dose was 1.8Gy per fraction (#) over 21-30 # in 14 patients. 7 patients had varying doses (2gy/# equivalent dose (α/ß 10) between 44.3Gy-56.3Gy). 2 patients also had HDR brachytherapy. One stopped treatment early due to toxicity, receiving 37.2gy in 1.8Gy per #. 18 had concurrent chemotherapy with fluoropyrimidines.

Intended follow up schedule was 3 monthly pelvic MRI, flexible sigmoidoscopy and CEA estimations, 6 monthly CT chest/abdomen/pelvis for 2 years (yearly thereafter).

All were alive at end of data collection. 24%(5) recurred over the 4 year period without distant metastases at 4,5,6, 18 and 23 months. At recurrence, on MRI, 2 patients were identified as stage 2; 3 patients were radiologically clear, but had biopsy proven locally recurrent disease. Salvage surgery was successfully completed in 3 patients with R0 resections and 1 patient was considering resection at the close of data collection. The remaining patient underwent HDR to rectal scar recurrence 7.5Gy in single fraction with cCR.

cCR rate was 18% over a median follow up of 12 months (range 1.8 months-50 months). 18 month progression free survival was 64%.

Conclusion

In select patients, opting for a watch and wait strategy is a safe & feasible option, promoting organ preservation at no detriment to overall survival. This could be suggested to the patient if there is CR at follow-up. In order to recognise the recurrence early, the defined follow up protocol should be intensive but this is difficult to achieve in practice. In our study, despite not meeting the intended follow up schedule, all relapses were successfully salvaged and occurred within the first 2 years. Our local recurrence rate is similar to the literature examining NACRT and surgery. The follow-up in our series is still short and so these patients should have long term surveillance. It is unclear whether adding in brachytherapy/contact radiotherapy will further reduce local recurrences in this group.

(1) Habr-Gama etal; IJROBP; March 15, 2014;Volume 88, Issue 4, Pages 822–828.