MRI TN Staging should be used with caution

when determining the need for preoperative

radiotherapy in rectal cancer

A Scala, CFM Evans, HS Tilney, DP Edwards, AM Gudgeon

Frimley Park Hospital NHS Foundation trust

NHS

Total Mesorectal Excision (TME)

Local Recurrence 3%

Disease free survival 80%

Heald RJ, Moran BJ, Ryall RD, MacFarlaine JK. Rectal cancer: the Basingstoke

experience of total mesorectal excision, 1978-1997. Arch Surg.1998

Aug;133(8):894-9

Pre-operative Radiotherapy

↓ local recurrence (4.4% - 9%) 1,2

No clear advantage on overall survival 1

1. Preoperative radiotherapy versus selective postoperative chemoradiotherapy in patients with rectal cancer

(MRC CR07 and NCIC-CTG C016): a multicentre, randomised trial. Lancet. Mar 7, 2009; 373(9666): 811–820.

2. The Swedish Rectal Cancer Trial: Long lasting benefits from radiotherapy on survival and local recurrence rate.

J Clin Oncol 2006: 23: 5644-50

Short Course Radiotherapy (SCRT)

Long course Chemo-radiotherapy (CRT)

↑ pelvic + perineal post surgical infection

↑ chronic bowel dysfunction

↑ urinary and sexual dysfunction (♂ + ♀)

↑ permanent sterility

↑ risk second malignancy

Marijnen CA, van de Velde CJ, Putter H, van den Brink M, Maas CP, Martijn H et al. Impact of short-term pre-operative radiotherapy on health-related

quality of life and sexual functioning in primary rectal cancer: report of a multicenter randomized trial. J Clin Oncol 2005 Mar 20;23:1847-58.

Birgisson H, Pahlman L, Glimeus B. Adverse effects of preoperative radiation therapy for rectal cancer: long term follow up of the Swedish Rectal

Cancer Trial. J Clin Oncol 2006; 23 8697 – 705

Birgisson H, Pahlman L, Gunnarsson U, Glimeus B. Occurrence of second cancers in patients treated with radiotherapy for rectal cancer J Clin Oncol

2005; 23 6126-31

SCRT / CRT toxicity

Guidelines for the management of colorectal cancer 3rd Edition

ACPGBI Guidelines

USA Guidelines

Preoperative staging

1. Mercury Study Group. Diagnostic accuracy of pre-operative magnetic resonance imaging in predicting curative

resection of rectal cancer: prospective observational study. BMJ 2006; 333(7572):779.

2. Bipat S. et al. Rectal cancer: local staging and assessment of lymph node involvement with endoluminal US, CT, and

MR imaging--a meta-analysis. Radiology. 2004 Sep;232(3):773-83

MRI predicted CRM status accuracy 96.7% 1

MRI LN involvement sensitivity / specificity: 55% / 76% 2

Assess accuracy of pre-operative loco-regional MRI

staging in rectal cancer in a single institution.

• Primary outcomes

- Concordance between MRI and pathological TN Staging

• Secondary outcomes

- CRM status

- Local recurrence

- Cancer survival

- Overall survival

Aim

Data base 1998 – 2013

All rectal cancer resections with pre-operative MRI without neo-adjuvant

SCRT or CRT

Comparison of MRI TN stage with pTN stage

- Neoadjuvant CRT if threatened CRM margins

- Three dedicated colorectal radiologists (Mercury Study)

- Surgery by colorectal specialists

Methods

MRI protocol

Royal Marsden Hospital MRI Rectal Cancer Staging protocol *

Pathology technique

Royal College of Pathology Guidelines

“Dataset for Colorectal Cancer” 2nd Edition 2007

TNM Stage 5th Edition

International Union Against Cancer (UICC)

Methods

* Brown G et al. Techniques and trouble-shooting in high spatial resolution thin slice MRI for rectal cancer. The British Journal

of Radiology. 2005 Mar;78(927):245-51.

Tumour site

Upper

Mid

Lower

87.0%

7.0%

Operation

Anterior resection

APER

Hartmanns

Panproctocolectomy

Results 289 Patients

Results 289 Patients

MRI Stage = p Stage

T 186 (64.3%)

N 166 (57.4%)

TN 119 (41.2%)

Results MRI T Stage

9 (90%)

51 (50%)

120 (74.7%)

6 (40%)

1 (10%)

31 (30.4%)

13 (8.2%)

20 (19.6%) 29 (17.9%)

9 (60%)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

T1 T2 T3 T4

Equal pStage Under-staged Over-staged

Results MRI N Stage

118 (71.1%)

30 (35.7%) 18 (43.9%)

38 (28.9%)

15 (17.9%)

39 (46.4%) 23 (56.1%)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

N0 N1 N2

Equal pStage Under-staged Over-staged

Results MRI N1/N2

125 patients

pN1/2, 70 56%

pN0, 55 44%

44% False Positive

Results CRM status

R0 resection 286 (99.0%)

CRM Involvement 3 (1.0%)

MRI pStage

T2N1 T4N1

T3N0 T4N1

T3N2 T3N2

Follow up 49 months ( 0 - 164)

Adjuvant chemotherapy 108 (37.4%)

Local recurrence 10 (3.5%)

Distant recurrence 46 (15.9%)

5yr overall survival 80%

5yr cancer survival 87.9%

Results Follow up

Results Follow up

MRI T3/4 N2 37 (12.8%)

2 Local Recurrence (5.4%)

• MRI TN stage should be used with caution when assessing

the need for pre-operative radiotherapy

• MRI CRM status correlates consistently with pathological

findings

• Preoperative CRT can be safely reserved for patients with

threatened CRM on MRI

• Good results can be achieved without using SCRT

Conclusions