With the advent of powerful gradient coil systems and high-resolution surface coils, magnetic resonance imaging (MRI) is appreciated to be able to accurately stage the extent the topographic relationship of a tumor to the mesorectal fascia and surrounding organs and tissues. MRI is currently the only imaging modality that is highly accurate in predicting whether or not it is likely that a tumor-free margin can be achieved and thus provides important information for planning of an effective therapeutic strategy, especially in patients with advanced rectal cancer. It enables selection of surgery versus chemotherapy and radiation as treatment for localized rectal cancer(2).
MRI is recommended in selected cases by the European Guideline(2). One notable difference between the NICE and the American NCCN guidelines is the use of ultrasound versus magnetic resonance imaging (MRI) for rectal cancer staging. In the US, however, ultrasound is used more frequently as a staging modality and has advantages for discerning early T1 and T2 tumors(3). Nevertheless, staging with MRI should be considered medically appropriate.
1. B. Glimelius et al, Rectal cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up, Ann Oncol (2010) 21 (suppl 5): v82-v86.
2.Christian Klessen, Patrik Rogalla, and Matthias Taupitz, Local staging of rectal cancer: the current role of MRI, Eur Radiol. 2007 February; 17(2): 379389.
3.Anne Lin, MD, FACS, FASCRS and Clifford Ko, MD, MS, MSHS, FACS, FASCRSColorectal Cancer Guideline Reflects International Practice Variations, National Guideline Clearinghouse, December 24, 2012, http://www.guideline.gov/expert/printView.aspx?id=39252
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