Abstract 98P
Background
Invasive Lobular Carcinoma (ILC) challenges standard-of-care imaging, with disease spread being underestimated and missed in many patients. WB-DWI/MRI has demonstrated its added value in detecting lymph node, peritoneal and bone metastases in breast cancer (PMID:35384456). Here, we aimed to assess the added value of WB-DWI/MRI to conventional imaging for staging of patients with ILC.
Methods
A retrospective single center analysis was performed of all patients with primary ILC undergoing WB-DWI/MRI in addition to standard locoregional and distant imaging staging including: mammography, breast ultrasound, breast MRI, FDG PET/CT, SPECT/CT combined with CT or with chest X-ray/liver ultrasound, at University Hospitals Leuven, Belgium between 2017 and 2023. Diagnostic accuracies between WB-DWI/MRI and conventional imaging staging were compared. Histopathology after surgery or biopsy, or the best valuable comparator including concurrent and follow-up clinical, biological and imaging information were used as reference standard.
Results
A total of 93 patients with ILC were included for analysis and their imaging reports were recorded. The diagnostic accuracy of WB-DWI/MRI vs. conventional imaging staging for each region are summarized in the table. WB-DWI/MRI improved detection of tumor sites in the contralateral breast (sensitivity 86.7% vs. 73.3%), detection of ipsilateral axillar lymphadenopathies (sensitivity 92.6% vs. 72.2%) and distant lymphadenopathies (sensitivity 93% vs. 71%). Furthermore, WB-DWI/MRI improved detection of distant metastases (accuracy 96.8% vs. 73.1%). In 25/93 (26.8%) of patients, WB-DWI/MRI detected distant metastases, missed at conventional imaging staging. Table: 98P
Comparison of WB-DWI/MRI with conventional imaging
| Focality | Contralateral breast | Ipsilateral axilla | Distant lymph nodes | Distant metastases | ||||||
| CLS | WB-DWI/MRI | CLS | WB-DWI/MRI | CLS | WB-DWI/MRI | CLS + CDS | WB-DWI/MRI | CDS | WB-DWI/MRI | |
| Sensitivity | 93.8% | 96.9% | 73.3% | 86.7% | 72.2% | 92.6% | 71.4% | 93.3% | 63.3% | 98.3% |
| Specificity | 95.1% | 96.7% | 98.7% | 98.7% | 94.9% | 82.1% | 100.0% | 98.7% | 90.9% | 93.9% |
| Positive predictive value | 90.9% | 93.9% | 91.7% | 92.9% | 95.1% | 87.7% | 100.0% | 93.3% | 92.7% | 96.7% |
| Negative predictive value | 96.7% | 98.3% | 95.1% | 97.5% | 71.2% | 88.9% | 95.2% | 98.7% | 57.7% | 96.9% |
| Accuracy | 94.6% | 96.8% | 94.6% | 96.8% | 81.7% | 88.2% | 95.7% | 97.9% | 73.1% | 96.8% |
Conclusions
WB-DWI/MRI adds value for primary staging of patients with ILC, by improving the detection of locoregional and distant disease extent. The use of WB-DWI/MRI aids in optimizing treatment choices for patients with ILC.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.