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? Journal Article
| Authors: | Lahaye, M. J.; Beets, G. L.; Engelen, S. M. E.; Kessels, A. G. H.; De Bruïne, A. P.; Kwee, H. W. S.; Van Engelshoven, J. M. A.; Van de Velde, C. J. H.; Beets-Tan, R. G. H. |
| Article Title: | 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? |
| Abstract: | Purpose: To prospectively determine diagnostic performance of predictive criteria for nodal restaging after radiation therapy with concomitant chemotherapy by using ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance (MR) imaging in patients with rectal cancer. Materials and Methods: After institutional review board approval and informed consent were obtained, 39 patients (24 men, 15 women; mean age, 64 years) with rectal cancer underwent USPIO-enhanced two-dimensional (2D) T2-weighted fast spin-echo, three-dimensional (3D) T1-weighted gradient-echo, and 3D T2*-weighted MR for restaging. Two observers evaluated nodes for border irregularity, short- and long-axis diameters, and estimated percentage of white region (<30%, 30%-50%, or >50%) within the node (3D T2*-weighted images). Ratio of the measured surface area of the white region within the black node to the measured surface area of the total node (Ratio<sub>A</sub>) was calculated. Signal intensity (SI) in gluteus muscle (SI<sub>GM</sub>) and in total node (SI<sub>TN</sub>) were used to calculate SI<sub>TN</sub>/SI<sub>GM</sub> ratio. Histopathologic findings were reference standard. Receiver operating characteristic (ROC) curves were compared and interobserver agreement was determined. Results: Lesion-by-lesion analysis was feasible in 201 lymph nodes. Area under the ROC curve (AUC) of border and short- and long-axis diameters for observer 1 were 0.85, 0.87, and 0.88 and for observer 2 were 0.70, 0.89, and 0.87, respectively. AUC for estimated percentage of white region within the node, Ratio<sub>A</sub>, and SI<sub>TN</sub>/SI<sub>GM</sub> ratio for observer 1 were 0.98, 0.99, and 0.62 and for observer 2 were 0.97, 0.98, and 0.65, respectively. AUC for USPIO-enhanced MR criteria was significantly better than AUC for conventional MR criteria (P < .01). All criteria except border irregularity and SI<sub>TN</sub>/S<sub>IGM</sub> ratio showed high interobserver agreement (κ > 0.79). Conclusion: The most reliable predictors for identifying benign nodes after radiation therapy with concomitant chemotherapy by using USPIO-enhanced MR imaging for restaging in patients with rectal cancer were estimated percentage of white region within the node and RatioA. Measurements on standard 2D T2-weighted fast spin-echo images versus primary staging results offer reasonably good accuracy to identify benign lymph nodes after therapy. © RSNA, 2009. |
| Keywords: | cancer chemotherapy; clinical article; controlled study; human tissue; treatment outcome; treatment response; aged; aged, 80 and over; middle aged; clinical trial; histopathology; fluorouracil; advanced cancer; area under the curve; cancer adjuvant therapy; cancer radiotherapy; neoadjuvant therapy; radiotherapy, adjuvant; cancer staging; nuclear magnetic resonance imaging; magnetic resonance imaging; lymph node metastasis; lymphatic metastasis; neoplasm staging; diagnostic accuracy; sensitivity and specificity; reproducibility of results; backache; contrast enhancement; carcinoma; predictor variable; headache; drug therapy; rectal neoplasms; rectum cancer; roc curve; urticaria; ultrasmall superparamagnetic iron oxide; rectum surgery |
| Journal Title: | Radiology |
| Volume: | 252 |
| Issue: | 1 |
| ISSN: | 0033-8419 |
| Publisher: | Radiological Society of North America, Inc. |
| Date Published: | 2009-07-01 |
| Start Page: | 81 |
| End Page: | 91 |
| Language: | English |
| DOI: | 10.1148/radiol.2521081364 |
| PUBMED: | 19403848 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 8" - "Export Date: 30 November 2010" - "CODEN: RADLA" - "Source: Scopus" |
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