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: 3.93). 02/2011; 18(8):2224-31. DOI: 10.1245/s10434-011-1607-5
Source: PubMed


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.

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Available from: Regina G H Beets-Tan, Oct 02, 2015
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    • "In the lower patient, no high signal is shown on DWI (f) and a complete tumor response (pT0) was confirmed at histology. Courtesy of Lambregts, et al. 39 "
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    ABSTRACT: Treatment of advanced colon and rectal cancer has significantly evolved with the introduction of neoadjuvant chemoradiation therapy so much that, along with more effective chemotherapy regimens, surgery has been considered unnecessary among some institutions for select patients. The tumor response to these treatments has also improved and ultimately has been shown to have a direct effect on prognosis. Yet, the best way to monitor that response, whether clinically, radiologically, or with laboratory findings, remains controversial. The authors' aim is to briefly review the options available and, more importantly, examine emerging and future options to assist in monitoring treatment response in cases of locally advanced rectal cancer and metastatic colon cancer.
    Journal of Cancer 01/2014; 5(1):44-57. DOI:10.7150/jca.7809 · 3.27 Impact Factor
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    • "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] . "
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    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 · 2.07 Impact Factor
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    • "Maas et al, who first reproduced the results of this strategy, used more sophisticated modalities, including MRI enhanced with novel contrast agents or diffusion-weighted MRI (4). Restaging MRI, consisting of standard T2-weighted MRI and diffusion-weighted MRI, significantly improved the sensitivity for selecting complete responders, with a specificity of >90%; i.e. the risk of underestimating the residual tumor was <10% (9). In the more recent ACOSOG Z6041 trial, which investigated the efficacy of pre-operative CRT and local excision for treating cT2N0 rectal cancer, a ycCR was concordant with a ypCR in 31 of 36 patients (10). "
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    ABSTRACT: Pre-operative chemoradiotherapy (CRT) for rectal cancer yields a complete tumor response in 10-30% of patients. There is an argument for omitting surgery in these patients, but this remains highly controversial and the supporting evidence based on long-term follow-up is lacking. The present study analyzed the long-term outcomes of five patients with cT3 or cT4 rectal cancer who showed a clinical complete response (ycCR) following pre-operative CRT and underwent no surgery. The ycCR status was determined 7-12 weeks after the completion of CRT using clinical, endoscopic and radiological studies, including magnetic resonance imaging and biopsy. The follow-up period was 54-101 months. Three patients had no tumor recurrence and were alive with no evidence of disease at 101, 100 and 93 months, respectively. One patient developed local recurrence at 59 months and another developed lung metastasis at 32 months. The two patients with tumor recurrence remained disease-free 42 and 22 months after salvage pelvic and thoracic surgery, respectively. Despite being a small series, the long-term survival outcomes of the present study indicate that a non-operative approach may be feasible for a proportion of rectal cancer patients who reveal a ycCR following pre-operative CRT.
    Oncology letters 12/2013; 6(6):1573-1576. DOI:10.3892/ol.2013.1596 · 1.55 Impact Factor
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