Diffusion-weighted magnetic resonance for prediction of response after neoadjuvant chemoradiation therapy for locally advanced rectal cancer: preliminary results of a monoinstitutional prospective study.

PURPOSE To evaluate diffusion-weighted imaging (DWI) for assessment of treatment response in locally advanced rectal cancer (LARC) 8 weeks after neoadjuvant chemoradiotherapy (CRT). METHODS AND MATERIALS A total of 28 patients with LARC underwent magnetic resonance imaging (MRI) prior to and 8 weeks after CRT. Tumor volume (TV) was calculated on T2-weighted MRI scans as well as the apparent diffusion coefficient (ADC) was calculated using Echo-planar DWI-sequences. All data were correlated to surgical results and histopathologic tumor regression grade (TRG), according to Mandard's classification. Post-treatment difference ADC (%ΔADC) and TV (%ΔTV) changes at 8 weeks were compared complete response (CR; TRG1) and non-complete response tumors (non-CR; TRG2-5). RESULTS The mean % ADC increase of CR group was significantly higher compared to non-CR group (77.2 ± 54.63% vs. 36.0 ± 29.44%; p = 0.05). Conversely, the mean % TV reduction did not significantly differ in CR group from non-CR group (73.7% vs. 63.77%; p = 0.21). Accordingly, the diagnostic accuracy of the mean % ADC increase to discriminate CR from non-CR group was significantly higher than that of the mean % TV reduction (0.913 vs. 0.658; p = 0.022). No correlation was found between mean % TV reduction and TRG (rho = 0.22; p = 0.3037), whereas a negative correlation between mean % ADC increase and TRG was recorded (r = -0.69; p = 0.006). CONCLUSION The mean % ADC increase appears to be a reliable tool to differentiate CR from non-CR after CRT in patients with LARC.

[1]  Peter Gibbs,et al.  Diffusion changes precede size reduction in neoadjuvant treatment of breast cancer. , 2006, Magnetic resonance imaging.

[2]  J. Borrás,et al.  Multidisciplinary Rectal Cancer Management: 2nd European Rectal Cancer Consensus Conference (EURECA-CC2). , 2009, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[3]  Lei Tang,et al.  Locally advanced rectal carcinoma treated with preoperative chemotherapy and radiation therapy: preliminary analysis of diffusion-weighted MR imaging for early detection of tumor histopathologic downstaging. , 2010, Radiology.

[4]  E. Urso,et al.  Complete Pathologic Response Following Preoperative Chemoradiation Therapy for Middle to Lower Rectal Cancer Is Not a Prognostic Factor for a Better Outcome , 2004, Diseases of the colon and rectum.

[5]  S. Maier,et al.  High-b-value diffusion-weighted MR imaging for pretreatment prediction and early monitoring of tumor response to therapy in mice. , 2004, Radiology.

[6]  Rainer Fietkau,et al.  Prognostic significance of tumor regression after preoperative chemoradiotherapy for rectal cancer. , 2005, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[7]  A. Crucitti,et al.  Locally advanced rectal cancer: MR imaging in prediction of response after preoperative chemotherapy and radiation therapy. , 2009, Radiology.

[8]  M. Rugge,et al.  The Potential of Restaging in the Prediction of Pathologic Response After Preoperative Chemoradiotherapy for Rectal Cancer , 2007, Annals of Surgical Oncology.

[9]  K. Keum,et al.  A comparative study of volumetric analysis, histopathologic downstaging, and tumor regression grade in evaluating tumor response in locally advanced rectal cancer following preoperative chemoradiation. , 2007, International journal of radiation oncology, biology, physics.

[10]  R. Newcombe,et al.  Morphologic predictors of lymph node status in rectal cancer with use of high-spatial-resolution MR imaging with histopathologic comparison. , 2003, Radiology.

[11]  Neil J Sebire,et al.  Tumors in pediatric patients at diffusion-weighted MR imaging: apparent diffusion coefficient and tumor cellularity. , 2007, Radiology.

[12]  Karin Haustermans,et al.  Long-term outcome in patients with a pathological complete response after chemoradiation for rectal cancer: a pooled analysis of individual patient data. , 2010, The Lancet. Oncology.

[13]  J. V. van Engelshoven,et al.  Locally advanced rectal cancer: MR imaging for restaging after neoadjuvant radiation therapy with concomitant chemotherapy. Part II. What are the criteria to predict involved lymph nodes? , 2009, Radiology.

[14]  Jae Young Lee,et al.  Apparent diffusion coefficient for evaluating tumour response to neoadjuvant chemoradiation therapy for locally advanced rectal cancer , 2011, European Radiology.

[15]  A. Maastricht.  Value of ADC measurements for nodal staging after chemoradiation in locally advanced rectal cancer—a per lesion validation study , 2011 .

[16]  Tae Hyun Kim,et al.  Usefulness of magnetic resonance volumetric evaluation in predicting response to preoperative concurrent chemoradiotherapy in patients with resectable rectal cancer. , 2005, International journal of radiation oncology, biology, physics.

[17]  Jae Young Lee,et al.  Locally advanced rectal cancer: added value of diffusion-weighted MR imaging in the evaluation of tumor response to neoadjuvant chemo- and radiation therapy. , 2009, Radiology.

[18]  Jan Wolber,et al.  Diffusion MRI for prediction of response of rectal cancer to chemoradiation , 2002, The Lancet.

[19]  Jeong-Sik Yu,et al.  Restaging of Rectal Cancer with MR Imaging after Concurrent Chemotherapy and Radiation Therapy. , 2010, Radiographics : a review publication of the Radiological Society of North America, Inc.

[20]  B. Turner.  International Union Against Cancer (UICC) , 1999 .

[21]  M. Guerrieri,et al.  A prospective randomized study with a 5-year minimum follow-up evaluation of transanal endoscopic microsurgery versus laparoscopic total mesorectal excision after neoadjuvant therapy , 2007, Surgical Endoscopy.

[22]  L. Ellis,et al.  Improved Overall Survival Among Responders to Preoperative Chemoradiation for Locally Advanced Rectal Cancer , 2001, American journal of clinical oncology.

[23]  J. Hartley,et al.  Magnetic resonance imaging accuracy in assessing tumour down‐staging following chemoradiation in rectal cancer , 2009, Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland.

[24]  Rainer Fietkau,et al.  Preoperative versus postoperative chemoradiotherapy for rectal cancer. , 2004, The New England journal of medicine.

[25]  J. Petiot,et al.  Pathologic assessment of tumor regression after preoperative chemoradiotherapy of esophageal carcinoma. Clinicopathologic correlations , 1994, Cancer.

[26]  Valentini,et al.  Multidisciplinary rectal cancer management , 2009 .

[27]  Stephan E Maier,et al.  Early detection of response to radiation therapy in patients with brain malignancies using conventional and high b-value diffusion-weighted magnetic resonance imaging. , 2003, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[28]  L. Shen,et al.  Apparent diffusion coefficient: potential imaging biomarker for prediction and early detection of response to chemotherapy in hepatic metastases. , 2008, Radiology.

[29]  K. Haustermans,et al.  Diffusion-Weighted MRI for Selection of Complete Responders After Chemoradiation for Locally Advanced Rectal Cancer: A Multicenter Study , 2011, Annals of Surgical Oncology.