Arceci Year Book of Oncology 2013

1. Auflage 2013
ISBN: 978-1-4557-7305-3
Verlag: Elsevier HealthScience EN
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, Band Volume 2013, 520 Seiten

Reihe: Year Books

The Year Book of Oncology brings you abstracts of the articles that reported the year's breakthrough developments in oncology, carefully selected from more than 500 journals worldwide. Expert commentaries evaluate the clinical importance of each article and discuss its application to your practice. There's no faster or easier way to stay informed Topics include Supportive Care, Breast Cancer, Gynecologic Cancers, Genitourinary Cancers, Hematologic Malignancies, Thoracic Cancer, Gastrointestinal Cancer and Cancer Biology. The Year Book of Oncology is available annually in November.

Autoren/Hrsg.

Arceci, Robert J.

Leseproben

Locally Advanced Breast Cancer: MR Imaging for Prediction of Response to Neoadjuvant Chemotherapy—Results from ACRIN 6657/I-SPY TRIAL
Hylton NM, For the ACRIN 6657 Trial Team and I-SPY 1 TRIAL Investigators (Univ of California, San Francisco; et al) Radiology 263:663-672, 2012§
M. Kalambo, MD, J. Stafford, PhD and W.T. Yang, MD Evidence Ranking B Expert Rating 3 Abstract
Purpose
To compare magnetic resonance (MR) imaging findings and clinical assessment for prediction of pathologic response to neoadjuvant chemotherapy (NACT) in patients with stage II or III breast cancer. Materials and Methods
The HIPAA-compliant protocol and the informed consent process were approved by the American College of Radiology Institutional Review Board and local-site institutional review boards. Women with invasive breast cancer of 3 cm or greater undergoing NACT with an anthracycline-based regimen, with or without a taxane, were enrolled between May 2002 and March 2006. MR imaging was performed before NACT (first examination), after one cycle of anthracyline-based treatment (second examination), between the anthracycline-based regimen and taxane (third examination), and after all chemotherapy and prior to surgery (fourth examination). MR imaging assessment included measurements of tumor longest diameter and volume and peak signal enhancement ratio. Clinical size was also recorded at each time point. Change in clinical and MR imaging predictor variables were compared for the ability to predict pathologic complete response (pCR) and residual cancer burden (RCB). Univariate and multivariate random-effects logistic regression models were used to characterize the ability of tumor response measurements to predict pathologic outcome, with area under the receiver operating characteristic curve (AUC) used as a summary statistic. Results
Data in 216 women (age range, 26–68 years) with two or more imaging time points were analyzed. For prediction of both pCR and RCB, MR imaging size measurements were superior to clinical examination at all time points, with tumor volume change showing the greatest relative benefit at the second MR imaging examination. AUC differences between MR imaging volume and clinical size predictors at the early, mid-, and posttreatment time points, respectively, were 0.14, 0.09, and 0.02 for prediction of pCR and 0.09, 0.07, and 0.05 for prediction of RCB. In multivariate analysis, the AUC for predicting pCR at the second imaging examination increased from 0.70 for volume alone to 0.73 when all four predictor variables were used. Additional predictive value was gained with adjustments for age and race. Conclusion
MR imaging findings are a stronger predictor of pathologic response to NACT than clinical assessment, with the greatest advantage observed with the use of volumetric measurement of tumor response early in treatment. Commentary
This prospective study by Hylton and colleagues of 216 patients was a companion imaging study to the Cancer and Leukemia Group B 150007 trial and compared magnetic resonance imaging (MRI) findings and clinical assessment for the prediction of pathologic response to NACT in patients with stage II or III breast cancer. The American College of Radiology Imaging Network 6657 study showed that MRI findings are a stronger predictor of pathologic response to NACT than is clinical assessment at all time points, and the advantage was greatest when MRI was used to measure tumor volume at the early treatment time point. The strengths of the study include the prospective design, patient sample size, standardization of time points for assessing tumor response by MRI, and impressive compliance rate of enrolled patients who returned for repeat imaging. In the setting of locally advanced breast cancer, NACT is introduced with the aim of reducing the size of the primary tumor and achieving breast conservation at surgery. In addition to reducing the overall tumor burden, NACT allows for the direct and early observation of the response to treatment, thereby allowing for treatment plan modifications early in the course of the disease, which leads to better clinical outcomes. After treatment, the primary tumor bed is surgically excised to verify tumor response and to obtain negative margins prior to the initiation of radiation therapy. The literature supports MRI as the most specific, yet relatively less sensitive, modality for predicting pCR when compared with mammography, sonography, and clinical examination.1 Moreover, a prospective study by Yeh and colleagues showed that although MRI demonstrated the best pathologic correlation, residual disease was either overestimated or underestimated in 26% of patients2; these findings were corroborated in a companion study by Shin and colleagues in 2011.3 In the present study by Hylton and colleagues, contrast-enhanced images at all imaging time points were analyzed using the single-enhancement ratio technique, with voxel-based comparison of both early and late contrast enhancement, a technique that is considered somewhat outdated and has recently been supplanted by dynamic contrast-enhanced high-temporal-resolution imaging that allows for the exploitation of pharmacokinetic modeling.4 Moreover, the criteria used for estimating the greatest extent of disease accounted for intervening areas of nonenhancing tissue on baseline MRI, an approach that may overestimate the overall tumor size. From a technological standpoint, it should be acknowledged that this study formally began nearly 10 years ago, using the nascent technology provided by vendors of breast MRI systems. Since that time, there have been substantial technological advancements in MRI systems that specifically affect breast MRI protocols. Improvements in static magnetic field homogeneity, radiofrequency amplifiers, and encoding gradients over the large, off-isocenter fields of view needed for breast MRI, as well as in the number of channels and the design of breast MRI–specific phased-array coils, have helped to improve image quality substantially. Additionally, 3-tesla systems have shown promise for breast MRI compared with the 1.5-tesla systems used in this study. An array of more advanced acquisition and image reconstruction techniques, such as parallel imaging for increased temporal resolution and Dixon techniques for more uniform fat suppression across large fields of view, may also increase breast MRI quality in modern systems. Additionally, postprocessing algorithms seek to reduce the impact of motion on subtracted images. Such techniques could affect the measurements reported in this study using both T2-weighted and 3-dimensional T1-weighted images, particularly those describing lesion size and enhancement kinetics. These comments do not detract from the current study but rather bolster the authors' conclusions. The results reported here using nascent breast MRI technology support further investigation of the effect of modern MRI approaches on the assessment of response to NACT. Although MRI is quickly emerging as a powerful tool for monitoring disease response to NACT, it has several limitations. While MRI has been shown to be a stronger predictor of pathologic response to NACT when compared with clinical assessment at all time points, a multivariate analysis including histologic subtype and receptor status was not performed in this study, and these are emerging variables that should be considered when assessing tumor response. Loo and colleagues recently reported statistically significant differences in the presence of residual tumor on pathologic analysis when tumors were categorized by histologic subtype.5 Residual tumor was most often documented at surgical excision following NACT in patients with estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative subtypes. Furthermore, imaging findings closely correlated with pathologic outcome in triple-negative and HER2-positive tumors and less predictively in ER-positive/HER2-negative tumors.6,7 The results reported in the present study by Hylton and colleagues substantiate the body of literature supporting MRI as the most specific and sensitive modality for image-based prediction of response to NACT. The study underscores the importance of continued investigation into how various histologic subtypes of breast carcinoma respond both histologically and radiographically to NACT and may help identify a subset of patients who would benefit most from MRI monitoring of chemotherapy response. References
1. Yuan, Y., Chen, X. S., Liu, S. Y., Shen, K. W. Accuracy of MRI in prediction of pathologic complete remission in breast cancer after preoperative therapy: a meta-analysis. AJR Am J Roentgenol. 2010; 195:260–268. 2. Yeh, E., Slanetz, P., Kopans, D. B., et al. Prospective comparison of mammography, sonography, and MRI in patients undergoing neoadjuvant chemotherapy for palpable breast cancer. AJR Am J Roentgenol. 2005; 184:868–877. 3. Shin, H. J., Kim, H. H., Ahn, J. H., et al. Comparison of mammography, sonography, MRI and clinical examination in patients with locally advanced or inflammatory...