Local staging of rectal cancer using combined pelvic phased‐array and endorectal coil MRI

Abstract

Purpose:To assess the accuracy of MRI, using a pelvic phased-array coil and an endorectal coil, for preoperative local staging of rectal cancer. Materials and Methods:Fifty-one patients (26 males and 25 females) with adenocarcinoma of the rectum underwent preoperative MRI and surgical resection of their tumors. Surgical pathology staging was compared to MRI staging (using the TNM classification) obtained both retrospectively by a reader blinded to surgical findings and prospectively (radiological reports). In addition, patients were stratified according to surgical treatment groups (stage I ϭ T1-2/N0, stage II ϭ T3/N0, stage III ϭ Tx/N1-2).Results: At pathology, 36 of 51 (68%) tumors were classified as T0-T2, and 15 (32%) were classified as T3. Overall, the sensitivity and specificity of MRI readings for T3 staging were 93% and 86%, respectively (positive predictive value (PPV) ϭ 74%, negative predictive value (NPV) ϭ 97%, accuracy ϭ 88%). MRI correctly predicted lymph node metastases in 11 of 13 patients with a sensitivity of 85% and specificity of 69% (PPV ϭ 58%, NPV ϭ 90%, accuracy ϭ 74%). MRI correctly predicted surgical treatment groups in 33 of 39 (85%) patients. Interobserver agreement between the retrospective and prospective readings was excellent ( ϭ 0.85) for prediction of T3 tumor and good ( ϭ 0.80) for prediction of nodal involvement. Conclusion:Combined endorectal and pelvic phased-array coil MRI can be used reliably to select which patients should receive preoperative chemoradiotherapy. It is highly predictive in terms of excluding T3 tumors, but still has limitations in predicting lymph node metastasis.

Endorectal ultrasonography versus phased-array magnetic resonance imaging for preoperative staging of rectal cancer

“…On the other hand, Tatli et al [27] in their study using gadolinium-enhanced combined pelvic-phased array and endo-rectal coil MRI, surgical treatment groups (stage 1 vs stage 2/3) were accurately predicted in 33 out of 39 patients (85%). Overall, a 93% sensitivity, 86% specificity, and 88% accuracy were achieved in the identification of mesorectal fat invasion.…”

MRI in local staging of rectal cancer: an update

“…Neoadjuvant chemoradiotherapy is not indicated in stage I tumors (confined to rectal wall with no nodal involvement), but is recommended for stage II (extends beyond the rectal wall, no nodal involvement) and stage III tumors (regional lymph node involvement). Therefore, in order to avoid unnecessary chemoradiation in stage I cancers, a reliable imaging modality is crucial to precisely define depth of invasion and to identify lymph node involvement (7). Current approach in the management of rectal cancer includes preoperative staging with different imaging modalities followed by neoadjuvant chemoradiotherapy (for stage II/III cancers).…”

Colorectal Carcinoma: Local Tumor Staging and Assessment of Lymph Node Metastasis by High‐Resolution MR Imaging in Surgical Specimens

“…Thus, high-resolution MR imaging was found to be a highly accurate method for evaluating depth of invasion by colorectal carcinoma. Its high accuracy appears to be attributable to the combination of high soft-tissue contrast and high spatial resolution that high-resolution MR imaging provides [8–20]. Its diagnostic accuracy, however, should be cautiously compared with previous studies that were performed in vivo, because the high-resolution MR imaging data in our study were obtained from fixed surgical specimens.…”