Local recurrence after rectal cancer resection is strongly related to the plane of surgical dissection and is further reduced by pre-operative short course radiotherapy. Preliminary results of the Medical Research Council (MRC) CR07 trial

Abstract

3512 Background: The MRC CR07 trial compared routine short course pre-operative radiotherapy (PRE) with selective post-operative chemo-radiation if there was involvement of the circumferential resection margin (CRM) (POST) and included a prospective pathological assessment of the quality of resection of the surgical specimen. Methods: A total of 1350 patients were randomised from 52 centres between March 1998 and August 2005. Median follow-up is 3 years. Trial pathologists were trained in histopathological assessment and reporting of the involvement of the CRM and plane of surgery (PoS) according to pre-set criteria describing the plane of dissection (Grade 1-muscularis plane: 2-intramesorectal plane: 3-mesorectal plane). 1232 patients were prospectively assessed for CRM and 1119 for PoS. Results: The CRM was involved (tumour ≤1mm) in 139 (11%) of resected specimens, and for these patients the 3-year local recurrence (LR), disease-free survival (DFS) and overall survival rates were 18%, 50% and 57%. For the 1093 patients with CRM-ve the respective rates were 7%, 81% and 84%. LR and DFS rates were associated with PoS (log-rank test p=0.0019 and p=0.0506 respectively), and in addition there was clear evidence of a reduction in LR and improvement in DFS rates in favour of PRE for all grades of quality of surgical assessment as shown in the table . Conclusions: The results indicate a strong association between the quality of surgery and the rates of local recurrence and disease-free survival, as well as a clear benefit from the addition of PRE to all grades of surgical dissection. Thus for patients with rectal cancer short-course pre-operative radiotherapy and good quality surgery can almost completely eliminate local recurrence. [Table: see text] No significant financial relationships to disclose.

Magnetic resonance imaging in rectal cancer downstaged using neoadjuvant chemoradiation: accuracy of prediction of tumour stage and circumferential resection margin status

“…An alternative theoretical explanation for apparent low MRI sensitivity for involved CRM postdownstaging CRT is suboptimal surgery with breach of the mesorectum or even the muscularis [22]. Considering the six patients in the current study in this category, macroscopically on examination by the pathologist two had had an ideal resection in the mesorectal fascial plane (grade 3 [22]) and in four the mesorectum was entered (grade 2, the intramesorectal plane [22]). In none was the muscularis propria breached (grade 1, the muscularis propria plane [22]).…”

“…Approximately, 30% of all rectal cancers are locally advanced at first presentation and in these patients achievement of disease-free margins is difficult with surgery alone. Circumferential resection margin status is a strong prognostic indicator in rectal cancer [2][3][4][5]22,25]. The risk of local recurrence and distant metastases is significantly increased with operative margin positivity resulting in worse overall survival.…”

“…Considering the six patients in the current study in this category, macroscopically on examination by the pathologist two had had an ideal resection in the mesorectal fascial plane (grade 3 [22]) and in four the mesorectum was entered (grade 2, the intramesorectal plane [22]). In none was the muscularis propria breached (grade 1, the muscularis propria plane [22]). Of the four patients where the mesorectum was entered, none had a macroscopic breach of their tumour.…”

Reporting colorectal cancer

“…In the MRC CR07 trial the quality of surgery rates improved and margin positivity rates fell substantially over the study. 38 We have identified differences between the quality of surgery of anterior resections and abdomino-perineal excisions. 39,40 However, for routine reporting only the assessment of the mesorectum has been tested in the context of randomized trials and we must await further trials before adopting the separate classification of such cases.…”

ASCO-Update 2006 - Neuigkeiten vom 42. Meeting der American Society of Clinical Oncology/ASCO 2006

“…Im präoperativen Arm lagen die Lokalrezidivraten bei zwischen 9 % (Muscularis propria), 6 % (intramesorektal) und betrug lediglich 1 %, wenn eine intakte TME mit der präoperativen Strahlentherapie kombiniert wurde. Bemerkenswerterweise konnte dieses Ergebnis einer extern qualitätsgesicherten TME bei mehr als 50 % der Patienten erzielt werden [43].…”