Preoperative rectal cancer staging with phased-array MR

Abstract

BackgroundWe retrospectively reviewed magnetic resonance (MR) images of 96 patients with diagnosis of rectal cancer to evaluate tumour stage (T stage), involvement of mesorectal fascia (MRF), and nodal metastasis (N stage).Our gold standard was histopathology.MethodsAll studies were performed with 1.5-T MR system (Symphony; Siemens Medical System, Erlangen, Germany) by using a phased-array coil. Our population was subdivided into two groups: the first one, formed by patients at T1-T2-T3, N0, M0 stage, whose underwent MR before surgery; the second group included patients at Tx N1 M0 and T3-T4 Nx M0 stage, whose underwent preoperative MR before neoadjuvant chemoradiation therapy and again 4-6 wks after the end of the treatment for the re-staging of disease.Our gold standard was histopathology.ResultsMR showed 81% overall agreement with histological findings for T and N stage prediction; for T stage, this rate increased up to 95% for pts of group I (48/96), while for group II (48/96) it decreased to 75%.Preoperative MR prediction of histologically involved MRF resulted very accurate (sensitivity 100%; specificity 100%) also after chemoradiation (sensitivity 100%; specificity 67%).ConclusionsPhased-array MRI was able to clearly estimate the entire mesorectal fat and surrounding pelvic structures resulting the ideal technique for local preoperative rectal cancer staging.

JOURNAL CLUB: Preoperative MRI Evaluation of Primary Rectal Cancer: Intrasubject Comparison With and Without Rectal Distention

“…Criteria based on border or signal intensity characteristics have proven more reliable than criteria based on size in determining nodal status. According to these criteria, MRI can be used to determine lymph node involvement with accuracy of 64-85% [1,9,15,18]. In this study the accuracy of N assessment for the two observers was 80.5% and 78.0%.…”

Routine use of positron-emission tomography/computed tomography for staging of primary colorectal cancer: Does it affect clinical management?

“…Likewise, MRI offers an 81% overall accuracy compared with histological findings for T and N staging [6]. Due to these imperfect results of CI studies, authors have investigated new preoperative imaging modalities for colorectal cancer; some authors suggest the use of PET/CT as an alternative option [15,18,19].…”

“…Although technical refinements have provided better quality for conventional imaging (CI) studies such as multi detector computed tomography (MDCT) and magnetic resonance imaging (MRI), complete correct preoperative staging has not yet been obtained. A recent study showed that the overall accuracy of MDCT was 86% in T staging and 84% in N staging [5]; another study reported that MRI provided an 81% overall agreement with histological findings for the T and N stages [6]. …”

Effectiveness of MRI for the Assessment of Mesorectal Fascia Involvement in Patients with Rectal Cancer: A Systematic Review and Meta-Analysis

“…It is much lower compared with the results by Al-Sukhni et al [16] (77%, 94% and 56.1, respectively), which is the latest study and also has the largest amount of patients among the three previous meta-analyses [14,15,16]. The following factors could have caused these differences: first, neo-ChRT is probably the most important factor; second, we only included studies that used a definition of MRF+ at ≤1 mm both in MRI and histopathology, and third, we have included studies that were published after Al-Sukhni's study [21,22,23,24]. …”