P-332 - MRI and DWI for TNM-stage assessment of colorectal cancer

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Colon Cancer
Rectal Cancer
Imaging, Diagnosis and Staging
Presenter M. Ayad
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors M. Ayad1, K. Boualga2
  • 1EHS Centre Anti Cancer, Blida/DZ
  • 2CAC, Blida/DZ

Abstract

Introduction

Colorectal cancer is the third most common cancer and the third leading cause of cancer death in men and women. 3-T MRI is used for preoperative diagnosis, TNM staging, and planning of surgical management of colorectal carcinoma.

Methods

Twenty-eight patients (18 men, 10 women) with clinically suspected rectal carcinoma underwent 3-T MRI. T2WI sequences with and without fat suppression; axial T1WI spin-echo sequences; T1WI GRE sequences with and without fat suppression; 3D fat-suppressed dynamic contrast-enhanced MRI and DWI were performed. MRI staging and pathologic findings were evaluated with kappa statistics

Results

Colorectal carcinoma was identified on MRI and confirmed histologically in 25 out of the 28 patients. MRI findings were correctly predictive of T category in 25 cases (accuracy, 89.2%). N stages (n 25 patients) were correctly determined in 15 (60%) patients. Three (12%) of 25 patients had metastatic lesions.

Conclusion

3-T High-resolution MRI is an accurate method delineating tumoral margins, mesorectal fat and mesorectal fascia involvement, nodes, and distant metastasis. For T Stage and Extramural Depth of Invasion, MRI is accurate for identifying T3 and T4 tumours; The MRI has difficulty in differentiating between T1 and T2 tumours. For N Stage, 3-T MRI can characterize lymph nodes as malignant according to the size (≥ 5 mm), shape (ovoid nodes > 5–6 mm), border (speculated or indistinct borders), and signal intensity (heterogeneous signal). DWI can be used to assess treatment response to preoperative chemo radiation and characterization of lymph node metastasis. For M Stage, MRI detects extramural invasion as serpiginous Tumor signal extending through the bowel wall adjacent to the signal void of the vessel.