Area Editoriale
OBJECTIVE: Toassess the accuracy of preoperative staging of rectal cancer with magneticresonance imaging to predict surgical circumferential resection margins.DESIGN: Prospective observational study of rectal cancers treated by colorectalmultidisciplinary teams between January 2002 and October 2003. SETTING: 11colorectal units in four European countries. PARTICIPANTS: 408 consecutivepatients presenting with all stages of rectal cancer and undergoing magneticresonance imaging before total mesorectal excision surgery andhistopathological assessment of the surgical specimen. MAIN OUTCOME MEASURES:Accuracy of magnetic resonance imaging in predicting a curative resection basedon the histological yardstick of presence or absence of tumour at the marginsof the specimen. RESULTS: 354 of the 408 patients had a clear circumferentialresection margin (87%, 95% confidence interval 83% to 90%). Specificity forprediction of a clear margin by magnetic resonance imaging was 92% (327/354,90% to 95%). High resolution scans were technically satisfactory in 93%(379/408). Surgical specimens were histopathologically graded as complete ormoderate in 80% (328/408), and the median lymph node harvest was 12 (range0-49). Magnetic resonance imaging predicted clear margins in 349 patients. Atsurgery 327 had clear margins (94%, 91% to 96%). CONCLUSION: High resolutionmagnetic resonance imaging accurately predicts whether the surgical resectionmargins will be clear or affected by tumour. This technique can be reproducedaccurately in multiple centres to predict curative resection and warns themultidisciplinary team of potential failure of surgery, thus enabling selectionof patients for preoperative treatment.Leggil'articolo: è full text!