The potential of restaging in the prediction of pathologic response after preoperative chemoradiotherapy for rectal cancer.
BACKGROUND
We performed this study to prospectively evaluate the postchemoradiotherapy performance of transrectal ultrasonography (TRUS), pelvic computed tomography (CT) scan and magnetic resonance imaging (MRI), and endoscopic biopsies for predicting the pathologic complete response of rectal cancer patients.


METHODS
Four weeks after completion of preoperative chemoradiotherapy, 46 consecutive patients with mid to low rectal cancer were prospectively evaluated by proctoscopy, TRUS, and pelvic CT scan and MRI. On the basis of T and N status, patients were classified as T0 or T1-4 and N-negative or N-positive. For each staging modality used, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. Findings were compared with the pathologic tumor-node-metastasis stage.


RESULTS
On histopathologic analysis, 12 patients had pT0 and 34 had pT1-4 lesions; out of 45 assessable patients, 9 were N-positive. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in predicting T status (T0 vs. T >or=1) were 77%, 33%, 74%, 36%, and 64%, respectively, for TRUS; 100%, 0%, 74%, not assessable, and 74% for CT; and 100%, 0%, 77%, not assessable, and 77% for MRI. The corresponding figures in predicting N status (N-negative vs. N-positive) were, respectively, 37%, 67%, 21%, 81%, and 61% for TRUS; 78%, 58%, 32%, 91%, and 62% for CT; and 33%, 74%, 25%, 81%, and 65% for MRI.


CONCLUSIONS
Current rectal cancer staging modalities after chemoradiotherapy allow good prediction of node-negative cases, although none of them is able to predict the pathologic complete response on the rectal wall.
Maretto
Isacco
I
Department of Oncological and Surgical Sciences, Clinica Chirurgica II, University of Padua, Via Giustiniani, 2, 35128, Padua, Italy.
Pomerri
Fabio
F
Pucciarelli
Salvatore
S
Mescoli
Claudia
C
Belluco
Enrico
E
Burzi
Simona
S
Rugge
Massimo
M
Muzzio
Pier Carlo
PC
Nitti
Donato
D
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001706:Biopsy; D017024:Chemotherapy, Adjuvant; D003082:Colectomy; D003113:Colonoscopy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy*; D012007:Rectum / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
D000970:Antineoplastic Agents