[Accuracy of preoperative magnetic resonance imaging in prediction of pathological stage and circumferential resection margin in rectal cancer].
OBJECTIVE
To evaluate the accuracy of preoperative magnetic resonance imaging (MRI) in prediction of pathological staging and involvement of circumferential resection margin (CRM) in rectal cancer.


METHODS
Fifty-three patients undergoing total mesorectal excision for biopsy-proven rectal cancer were assessed prospectively using high-resolution MRI for tumour (T) and mesorectal nodal (N) staging as well as CRM status using the depth of tumour spread, tumour node metastasis and CRM involvement. Preoperative MRI assessment of these prognostic factors was compared with the histopathological findings in carefully matched whole-mount sections of the specimen.


RESULTS
MRI correctly staged the tumor in 41 patients, understaged in 8, and overstaged in 4. The accuracy of T stage was 77.4% (41/53). There was ageneric correlation between pathologic and MRI tumor staging (Kappa = 0.602, P < 0.001). Node status was correctly staged in 37 patients, overstaged in 10, and understaged in 6. The accuracy of node staging was 69.8% (37/53), sensitivity was 75% (18/24), and specificity was 65.5% (19/29). The correlation between pathologic and MRI node staging was poor (Kappa = 0.399, P = 0.003). The CRM status was correctly reported in 51 patients, overstaged in 1, and understaged in 1. The accuracy of CRM status was 96.2% (51/53), sensitivity was 80% (1/5), and specificity was 97.9% (47/48). There was a good correlation between pathologic and MRI CRM involvement (Kappa = 0.779, P < 0.001).


CONCLUSIONS
Preoperative MRI provides poor predictive data as to subsequent pathologic tumor and mesorectal node stage, but does produce reliable prediction of clear CRM.
Jiang
Jin-bo
JB
Department of General Surgery, Qilu hospital of Shandong University, Jinan 250012, China.
Dai
Yong
Y
Zhang
Xiao-ming
XM
Li
Chuan-fu
CF
Jin
Zu-tao
ZT
Bi
Dong-song
DS
Sun
Jing-zhong
JZ
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D016246:Lymphocytes, Tumor-Infiltrating / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D011300:Preoperative Care; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery; D015203:Reproducibility of Results