Original StudyDiagnostic Performance of Fused Diffusion-Weighted Imaging Using T1-Weighted Imaging for Axillary Nodal Staging in Patients With Early Breast Cancer
Graphical abstract
We evaluate the diagnostic performance of fused diffusion-weighted imaging (DWI) for axillary nodal staging in patients with early breast cancer. Areas under the receiver operating characteristic curve of both readers for axillary nodal staging were 0.676 and 0.603 for non–fat-suppressed (non-FS) T1WI, 0.749 and 0.727 for T2WI, and 0.838 and 0.790 for fused DWI. Fused DWI showed better diagnostic performance than conventional T2WI and non-FS T1WI.
Introduction
Axillary lymph node metastasis is an important prognostic factor in patients with breast cancer, and surgical procedures, such as sentinel lymph node biopsy (SLNB), axillary lymph node dissection (ALND), or postsurgical treatment, may be altered according to its presence.1 ALND has been recommended after pathologic confirmation by SLNB, ultrasound-guided axillary lymph node biopsy, or aspiration.2 SLNB has recently replaced routine ALND in the clinical setting, and is a routine surgical procedure performed to avoid unnecessary ALND.3 However, SLNB is also an invasive procedure with associated complications, such as seroma, hematoma, lymphedema, and pain.4 Recent research has focused on developing noninvasive procedures for accurately predicting axillary nodal status and replacing SLNB. A recent prospective multicenter study even omitted SLNB in patients with early breast cancer; however, the clinical value of SLNB remains superior in many ways.5 Several previous studies have suggested techniques for noninvasively predicting the axillary status or for replacing SLNB; although their results were promising and the techniques had relatively high accuracy, they were not sufficiently high enough to substitute SLNB.6, 7, 8, 9
Magnetic resonance imaging (MRI) is widely used in the preoperative evaluation of breast cancer. Staging of lymph node metastasis using MRI is usually based on size and additional morphologic characteristics, such as irregular margin, inhomogeneous cortex, perifocal edema, or asymmetry.9 However, using size and morphology as criteria for identifying metastatic and nonmetastatic lymph nodes has limitations in discriminating enlarged reactive lymph nodes from small malignant lymph nodes. Moreover, recent technical advances in MRI have improved the detection and accuracy of axillary lymph node metastasis by applying diffusion-weighted imaging (DWI) or dedicated high–spatial-resolution axillary MRI sequences.6, 7, 10, 11 DWI is a noncontrast technique that can be easily performed, and it measures intracellular water movement.6, 12, 13, 14 Several recent studies have evaluated the performance of DWI in evaluating axillary lymph node metastasis,6, 8, 10, 15, 16, 17, 18 but their results were inconsistent. Although the spatial resolution of DWI has improved, it still has limitations, such as low spatial resolution and poor anatomical localization. These limitations may be overcome by fusion MRI using T1-weighted imaging (T1WI) and high b-value DWI (fused DWI using T1WI), which can simultaneously offer anatomical and functional data. Few recent studies using fusion MRI combining high b-value DWI and T2-weighted imaging (T2WI) have shown promising results in patients with abdominal and pelvic malignancies, such as prostate, endometrial, cervical, breast, and pelvic lymph node cancers.19, 20, 21, 22, 23, 24 In conventional breast MRI, T1WI is essential for anatomical evaluation with high spatial resolution. Therefore, we hypothesized that fused DWI using T1WI may provide better diagnostic accuracy than conventional MRI does for the evaluation of axillary lymph node metastasis in patients with early breast cancer. To our knowledge, this is the first study to conduct such an evaluation. The purpose of our study was to investigate the clinical utility of fused DWI using T1WI (3-T) MRI for evaluating axillary lymph node metastasis in patients with early breast cancer.
Section snippets
Patients
Our institutional review board approved this retrospective observational study and waived informed consent. Between August 2014 and March 2015, 1850 patients underwent breast MRI. Among them, we selected patients who met the following inclusion criteria: (1) patients who underwent DWI using readout-segmented echo-planar imaging (rs-EPI) using a 3-T MR scanner, (2) patients with early stage I or II breast cancer, and (3) patients who were able to provide detailed review of pathology with
Patients
Patient characteristics according to the status of lymph node metastasis (nonmacrometastasis and macrometastasis) are summarized as follows. Among the 149 lymph nodes tested, 99 (66.4%) were benign, 11 (7.4%) showed micrometastasis, and 39 (26.2%) showed macrometastasis. No patients had isolated tumor cells (≤ 0.2 mm) within an axillary lymph node on the surgical specimens. Nodes showing macrometastasis were subclassified according to the tumor size within the lymph node as follows: (1) 46%
Discussion
In our study, we evaluated the role of fused DWI using T1WI to evaluate the status of axillary lymph node metastasis in patients with early breast cancer. Fused DWI using T1WI alone showed AUCs of 0.838 for reader 1 and 0.790 for reader 2. NPVs of 84% for reader 1 and 86% for reader 2 and specificities of 90% for reader 1 and 92% for reader 2 were obtained in the prediction of axillary metastasis on the patient-to-patient level. The diagnostic performance of fused DWI using T1WI was better than
Conclusion
In conclusion, fused DWI using T1WI showed better diagnostic performance than the conventional non-FS T1WI and T2WI for the axillary nodal staging in patients with early breast cancer. Moreover, the addition of axillary lymph node ADC and tumor ADC to the qualitative assessment of fused DWI using T1WI further improved its diagnostic performance for the prediction of axillary lymph node metastasis. Nevertheless, future large-scale prospective studies are required to confirm our results.
Disclosure
The authors have stated that they have no conflicts of interest.
References (36)
- et al.
Management of the axilla in early breast cancer patients in the genomic era
Ann Oncol
(2013) - et al.
Comparison of morbidity between axillary lymph node dissection and sentinel node biopsy
Eur J Surg Oncol
(2003) - et al.
Sentinel-lymph-node biopsy in patients with breast cancer before and after neoadjuvant chemotherapy (SENTINA): a prospective, multicentre cohort study
Lancet Oncol
(2013) - et al.
A new, preoperative, MRI-based scoring system for diagnosing malignant axillary lymph nodes in women evaluated for breast cancer
Eur J Radiol
(2012) - et al.
Magnetic resonance for assessment of axillary lymph node status in early breast cancer: a systematic review and meta-analysis
Eur J Surg Oncol
(2011) - et al.
Detection of axillary node metastasis using diffusion-weighted MRI in breast cancer
Clin Imaging
(2013) - et al.
Differentiation between benign and malignant breast lesions using quantitative diffusion-weighted sequence on 3 T MRI
Clin Radiol
(2014) - et al.
Body diffusion-weighted MR imaging using high b-value for malignant tumor screening: usefulness and necessity of referring to T2-weighted images and creating fusion images
Acad Radiol
(2007) - et al.
Comparison between malignant and benign abdominal lymph nodes on diffusion-weighted imaging
Acad Radiol
(2008) - et al.
The need for lymph node dissection in nonmetastatic breast cancer
Annu Rev Med
(2013)
Prospective observational study of sentinel lymphadenectomy without further axillary dissection in patients with sentinel node-negative breast cancer
J Clin Oncol
Accuracy of unenhanced MR imaging in the detection of axillary lymph node metastasis: study of reproducibility and reliability
Radiology
Diagnostic performance of dedicated axillary T2- and diffusion-weighted MR imaging for nodal staging in breast cancer
Radiology
Diffusion-weighted magnetic resonance imaging in the characterization of axillary lymph nodes in patients with breast cancer
J Magn Reson Imaging
Application of MR mammography beyond local staging: is there a potential to accurately assess axillary lymph nodes? Evaluation of an extended protocol in an initial prospective study
AJR Am J Roentgenol
Quantitative diffusion imaging in breast cancer: a clinical prospective study
J Magn Reson Imaging
Diffusion-weighted imaging of malignant breast tumors: the usefulness of apparent diffusion coefficient (ADC) value and ADC map for the detection of malignant breast tumors and evaluation of cancer extension
J Comput Assist Tomogr
Diffusion-weighted imaging of breast cancer with the sensitivity encoding technique: analysis of the apparent diffusion coefficient value
Magn Reson Med Sci
Cited by (14)
Efficient Axillary Lymph Node Detection Via Two-stage Spatial-information-fusion-based CNN
2022, Computer Methods and Programs in BiomedicineConvolutional Neural Network of Multiparametric MRI Accurately Detects Axillary Lymph Node Metastasis in Breast Cancer Patients With Pre Neoadjuvant Chemotherapy
2022, Clinical Breast CancerCitation Excerpt :While grossly enlarged aLNs (ie, palpable) can be readily detected by MRI, smaller aLNs harboring micro-metastasis may not be readily distinguishable from normal nodes. MRI nodal staging to date has moderate to poor sensitivity and specificity10-14 and is currently not consistently used as part of the standard of care. Artificial intelligence is increasingly being used in radiology.15-18
Preoperative Prediction of Axillary Lymph Node Metastasis in Breast Cancer Using CNN Based on Multiparametric MRI
2022, Journal of Magnetic Resonance Imaging