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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Rectal cancer accounts for a relevant part of colorectal cancer cases, with a mortality of 4-10/100000 per year. The development of locoregional recurrences and the occurrence of distant metastases both influences the prognosis of these patients. In the last two decades, new multimodality strategies have improved the prognosis of locally advanced rectal cancer with a significant reduction of local relapse and an increase in terms of overall survival. Radical surgery still remains the principal curative treatment and the introduction of total mesorectal excision has significantly achieved a reduction in terms of local recurrence rates. The employment of neoadjuvant treatment, delivered before surgery, also achieved an improved local control and an increased sphincter preservation rate in low-lying tumors, with an acceptable acute and late toxicity. This review describes the multidisciplinary management of rectal cancer, focusing on the effectiveness of neoadjuvant chemoradiotherapy and of post-operative adjuvant chemotherapy both in the standard combined modality treatment programs and in the ongoing research to improve these regimens.
    World Journal of Gastroenterology 12/2014; 20(46):17279-17287. DOI:10.3748/wjg.v20.i46.17279 · 2.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Neoadjuvant chemoradiation (CRT) is considered one of the preferred treatment strategies for patients with locally advanced rectal cancer. This strategy may lead to significant tumor regression, ultimately leading to a complete pathologic response in up to 42% of patients. Assessment of tumor response following CRT and before radical surgery may identify patients with a complete clinical response who could possibly be managed nonoperatively with strict follow-up (watch-and-wait strategy). The present article deals with critical issues regarding appropriate selection of patients for this approach. Copyright © 2015 Elsevier Inc. All rights reserved.
    Hematology/Oncology Clinics of North America 02/2015; 29(1):135-151. DOI:10.1016/j.hoc.2014.09.004 · 2.07 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dramatic advances in image quality over the past few years have made diffusion-weighted magnetic resonance imaging (DW-MRI) a promising tool for rectal lesion evaluation. DW-MRI derives its image contrast from differences in the motion of water molecules between tissues. Such imaging can be performed quickly without the need for the administration of exogenous contrast medium. The technique yields qualitative and quantitative information that reflects changes at a cellular level and provides information about tumor cellularity and the integrity of cell membranes. The sensitivity to diffusion is obtained by applying two bipolar diffusion-sensitizing gradients to a standard T2-weighted spin echo sequence. The diffusion-sensitivity can be varied by adjusting the “b-factor”, which represents the gradient duration, gradient amplitude and the time interval between the two gradients. The higher the b-value, the greater the signal attenuation from moving water protons. In this review, technical considerations relatively to image acquisition and to quantification methods applied to rectal DW-MRI are discussed. The current clinical applications of DW-MRI, either in the field of inflammatory or neoplastic rectal disease are reviewed. Also, limitations, mainly in terms of persistent lack of standardization or evaluation of tumoral response, and future directions of rectal DW-MRI are discussed. The potential utility of DW-MRI for the evaluation of rectal tumor response is on its way to being admitted but future well-designed and multicenter studies, as well as standardization of DW-MRI, are still required before a consensus can be reached upon how and when to use DW-MRI.
    Critical Reviews in Oncology/Hematology 12/2014; 92(3). DOI:10.1016/j.critrevonc.2014.07.002 · 4.05 Impact Factor