Diffusion-Weighted MRI for Selection of Complete Responders After Chemoradiation for Locally Advanced Rectal Cancer: A Multicenter Study

Department of Radiology, Maastricht University Medical Center, Maastricht, The Netherlands.
Annals of Surgical Oncology (Impact Factor: 3.94). 02/2011; 18(8):2224-31. DOI: 10.1245/s10434-011-1607-5
Source: PubMed

ABSTRACT In 10-24% of patients with rectal cancer who are treated with neoadjuvant chemoradiation, no residual tumor is found after surgery (ypT0). When accurately selected, these complete responders might be considered for less invasive treatments instead of standard surgery. So far, no imaging method has proven reliable. This study was designed to assess the accuracy of diffusion-weighted MRI (DWI) in addition to standard rectal MRI for selection of complete responders after chemoradiation.
A total of 120 patients with locally advanced rectal cancer from three university hospitals underwent chemoradiation followed by a restaging MRI (1.5T), consisting of standard T2W-MRI and DWI (b0-1000). Three independent readers first scored the standard MRI only for the likelihood of a complete response using a 5-point confidence score, after which the DWI images were added and the scoring was repeated. Histology (ypT0 vs. ypT1-4) was the standard reference. Diagnostic performance for selection of complete responders and interobserver agreement were compared for the two readings.
Twenty-five of 120 patients had a complete response (ypT0). Areas under the ROC-curve for the three readers improved from 0.76, 0.68, and 0.58, using only standard MRI, to 0.8, 0.8, and 0.78 after addition of DWI (P = 0.39, 0.02, and 0.002). Sensitivity for selection of complete responders ranged from 0-40% on standard MRI versus 52-64% after addition of DWI. Specificity was equally high (89-98%) for both reading sessions. Interobserver agreement improved from κ 0.2-0.32 on standard MRI to 0.51-0.55 after addition of DWI.
Addition of DWI to standard rectal MRI improves the selection of complete responders after chemoradiation.

  • Source
    • "Monitoring of chemoradiotherapy of rectal carcinoma 7 ADC values. Using the ADC, several groups showed promising results for better differentiation between post-therapeutic scar tissue (representing complete remission ) and residual tumor in patients 1 month or more after completion of neoadjuvant CRT [9] [37] . "
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: The aim of this study was to characterize and understand the therapy-induced changes in diffusion parameters in rectal carcinoma under chemoradiotherapy (CRT). The current literature shows conflicting results in this regard. We applied the intravoxel incoherent motion model, which allows for the differentiation between diffusion (D) and perfusion (f) effects, to further elucidate potential underlying causes for these divergent reports. Materials and methods: Eighteen patients with primary rectal carcinoma undergoing preoperative CRT were examined before, during, and after neoadjuvant CRT using diffusion-weighted imaging. Using the intravoxel incoherent motion approach, f and D were extracted and compared with postoperative tumor downstaging and volume. Results: Initial diffusion-derived parameters were within a narrow range (D1 = 0.94 ± 0.12 × 10(-3) mm(2)/s). At follow-up, D rose significantly (D2 = 1.18 ± 0.13 × 10(-3) mm(2)/s; P < 0.0001) and continued to increase significantly after CRT (D3 = 1.24 ± 0.14 × 10(-3) mm(2)/s; P < 0.0001). The perfusion fraction f did not change significantly (f1 = 9.4 ± 2.0%, f2 = 9.4 ± 1.7%, f3 = 9.5 ± 2.7%). Mean volume (V) decreased significantly (V1 = 16,992 ± 13,083 mm(3); V2 = 12,793 ± 8317 mm(3), V3 = 9718 ± 6154 mm(3)). T-downstaging (10:18 patients) showed no significant correlation with diffusion-derived parameters. Conclusions: Conflicting results in the literature considering apparent diffusion coefficient (ADC) changes in rectal carcinoma under CRT for patients showing T-downstaging are unlikely to be due to perfusion effects. Our data support the view that under effective therapy, an increase in D/ADC can be observed.
    Cancer Imaging 12/2013; 13(4):548-556. DOI:10.1102/1470-7330.2013.0045 · 1.29 Impact Factor
  • Source
    • "(Kang et al. 2010) With the introduction of diffusion-weighted (DW) MRI, significant amount of interest has been focused on this particular study. In a recent multicentric study, three trained radiologist reviewed 120 patients, comparing standard MRI with DW MRI and all them found improvement in sensitivity and specificity rates using DW MRI.(Lambregts et al. 2011) Another recent report showed that post-CRT volumetry on DW-MR images were significantly more accurate than on T2-weighted MR images to assess a CR after CRT. (Curvo-Semedo et al. 2011) Still further studies are needed before these tools are definitively incorporated into clinical practice. "
    Rectal Cancer - A Multidisciplinary Approach to Management, 10/2011; , ISBN: 978-953-307-758-1
  • [Show abstract] [Hide abstract]
    ABSTRACT: Until recently, there has been uncertainty regarding the exact role, importance, and validity of MRI in restaging rectal cancers after preoperative treatment. MRI tumor reassessment has wide-ranging implications, for example, altering surgical planning, timing of surgery, and potential deferral of surgery for MRI-identified good responders. Several approaches for restaging rectal cancer after treatment have been proposed, for example, T staging, volume reduction of tumor, MRI tumor regression grading, and diffusion-weighted-imaging assessment. Likewise several approaches to restaging the potential resection margin and nodal disease have also been investigated. This article seeks to review the evidence for each of the proposed approaches to restage rectal cancer after chemoradiotherapy and concludes with recommendations for current clinical practice.
    Current Colorectal Cancer Reports 06/2013; 9(2). DOI:10.1007/s11888-013-0169-2
Show more