Whole-body diffusion-weighted MRI for operability assessment in patients with colorectal cancer and peritoneal metastases

Abstract

BackgroundCorrect staging of patients with colorectal cancer is of utmost importance for the prediction of operability. Although computed tomography (CT) has a good overall performance, estimation of peritoneal cancer spread is a known weakness, a problem that cannot always be overcome by Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT); especially in infiltrative and miliary disease spread. Due to its high spatial and contrast resolution magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) might have a better performance. Our aim was to evaluate the added value of whole-body diffusion-weighted MRI (WB-DWI/MRI) to CT for prediction of peritoneal cancer spread and operability assessment in colorectal cancer patients with clinically suspected peritoneal carcinomatosis (PC).MethodsThis institutional review board approved retrospective study included sixty colorectal cancer patients who underwent WB-DWI/MRI in addition to CT for clinically suspected peritoneal metastases. WB-DWI/MRI and CT were assessed for detecting PC following the peritoneal cancer index (PCI), determination of PCI-score categorized as PC < 12, PCI = 12–15 and PCI > 15, detection of nodal and distant metastases and estimation of overall operability. Histopathology after surgery and biopsy and/or 6 months follow-up were used as reference standard.ResultsFor detection of PC, CT had 43.2% sensitivity, 95.6% specificity, 84.5% positive predictive value (PPV) and 75.2% negative predictive value (NPV). WB-DWI/MRI had 97.8% sensitivity, 93.2% specificity, 88.9% PPV and 98.7% NPV. WB-DWI/MRI enabled better detection of inoperable distant metastases (all 12 patients) than CT (2/12 patients) and significantly improved prediction of PCI category [WB-DWI/MRI PCI < 12: 37/39 patients (94.9%); PCI = 12–15: 4/4 patients (100%); PCI > 15: 16/17 patients (94.1%) versus CT PCI < 12: 38/39 patients (97.4%); PCI = 12–15: 0/4 patients (0%); PCI > 15: 2/17 patients (11.8%); p < 0.0001)]. WB-DWI/MRI improved prediction of inoperability over CT with 90.6% sensitivity compared to 25% (p < 0.0001).ConclusionsWB-DWI/MRI significantly outperformed CT for estimation of spread of PC, overall staging and prediction of operability. Pending validation in larger prospective trials, WB-DWI/MRI could be used to guide surgical planning and minimize unnecessary exploratory laparotomies.

Magnetic Resonance Imaging With Diffuse Weighted Imaging and Computed Tomography With Intravenous Contrast in Staging of Disseminated Ovarian, Stomach, Colorectal Cancer

“…Compared with other studies of the efficacy and relative efficacy of DWI/MRI in colorectal cancer [10,11], ovarian cancer [12,13] and stomach cancer [14,15], similar results are obtained, illustrating the reproducibility of the experiment regardless of the treatment center used, study protocols, and subjective evaluation of PCI ranking results. The obtained results allow us to recommend DWI/MRI for pre-operative staging at all three investigated localizations of the tumour process.…”

<p>The Validity of Registered Synchronous Peritoneal Metastases from Colorectal Cancer in the Danish Medical Registries</p>

“…The diagnosis of PM is in its nature challenging to verify for clinicians; it does not necessarily rely on a histopathological verification, the sensitivity of a preoperative CT scan is low, and there is often a discrepancy between the radiological observed extent of peritoneal involvement and the findings during surgical exploration. 11,27 Clinicians are only allowed to register diagnoses with a high degree of certainty, so a diagnosis that is rarely histopathological verified, as PM, may be underreported. Our results show that the completeness in the DNPatR is 19% but the PPV is 76%.…”

“…10 Currently, no radiological imaging is superior to an intra-operative assessment of the peritoneal cavity. 11 Registries contain large comprehensive data, and the registration of S-PM enables clinicians and researchers to monitor prevalence and incidence along with treatment methods, mortality rates and the prognosis. However, this relies on the validity of S-PM data.…”

Impact of intratumor heterogeneity on diffusion-weighted MRI as a prognostic indicator in lower rectal cancer

“…The e cacy of DWI images of MRI for diagnosing primary tumors, lymph node metastasis, and distant metastasis, is similar to that of positron emission tomography-computed tomography (PET-CT) [22].…”