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Magnetic resonance imaging predicts circumferential resection margin status in patients receiving preoperative chemoradiotherapy for rectal cancer
Author(s) -
Hancock L.,
Forde C.,
Bradbury J.,
Mortensen N.,
Gleeson F.
Publication year - 2007
Publication title -
colorectal disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.029
H-Index - 89
eISSN - 1463-1318
pISSN - 1462-8910
DOI - 10.1111/j.1463-1318.2006.01133_7.x
Subject(s) - medicine , colorectal cancer , magnetic resonance imaging , chemoradiotherapy , radiology , biopsy , preoperative care , resection margin , cancer , radiation therapy , surgery , resection
Objective: Accurate tumour re‐assessment after down‐sizing preoperative chemoradiotherapy (CRT) for locally advanced middle and lower rectal cancer provides valuable prognostic information prior to surgical resection. We assessed the accuracy of post‐CRT magnetic resonance imaging (MRI) in predicting circumferential resection margin status. The accuracy of MRI in staging chemoradiation down‐sized rectal tumours was also assessed. Method: Patients from a single tertiary referral centre who received preoperative CRT for biopsy‐proven rectal cancer between January 2003 and February 2005 were identified from a database. All patients received long‐course CRT (50Gy over 5 weeks and five‐fluorouracil/leucovorin) prior to surgery. A comprehensive MRI reporting proforma was completed for each patient and results were compared directly with histological specimens. Results: A total of 50 patients were eligible for the study. The overall accuracy for predicting circumferential resection margin status was 76% (38/50, P = 0.006, sensitivity = 96.9%, specificity = 73.8%, negative predictive value = 96.9%). For T staging MRI was accurate in 52% (26/50) and for nodal staging MRI was correct in 60% (30/50). Venous invasion was predicted in 66% (33/50, P = 0.04). A radiological rectal cancer regression grade was derived and this correlated with histological rectal cancer regression grade in 65% (32/49). Conclusion: This study demonstrates that post‐CRT MRI is accurate in predicting the circumferential resection margin status which provides useful prognostic information prior to surgery.