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Published on: May 24, 2024
Integrated [18F]FAPI-42 PET/MR improves diagnostic accuracy in breast cancer: comparison with simultaneously acquired
Peng Hou1,2, Jie Lv2, Weige Tan3
1Department of Radiology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan 2nd Road, Guangzhou, 510080, China.
Purpose:
This study assessed the diagnostic efficacy of fluorine-18-labeled fibroblast activation protein inhibitor 42 ([18F]FAPI-42) PET/MR versus simultaneously acquired breast MRI in identifying primary breast lesions and axillary lymph node metastases.
Methods:
A prospective study enrolled 64 women with BI-RADS 4 or 5 lesions identified through mammography or ultrasound. All participants underwent contrast-enhanced [18F]FAPI PET/MRI scans of the breast. Histology and imaging follow-up (median 11.5 months) were used as the gold standard. Primary lesions and lymph nodes were assessed using three imaging modalities: breast MRI, qualitative/quantitative [18F]FAPI PET, and integrated [18F]FAPI PET/MR. Quantitative PET parameters comprised the maximum standardized uptake value (SUVmax) and the tumor-to-background ratio (TBR). Receiver operating characteristic analysis assessed diagnostic performance, while net reclassification improvement (NRI) evaluated the diagnostic enhancement of PET/MR compared to breast MRI.
Results:
The study included 114 breast lesions (89 malignant, 25 benign) and 114 lymph node groups (82 malignant, 32 benign). In detecting primary breast lesions, the quantitative PET/MR based on TBR (PET/MR-TBR) demonstrated superior specificity over breast MRI (96% vs. 68%, P = 0.016), corresponding to a marked reduction in false positive rate from 32% (8/25) to 4.0% (1/25; P = 0.027), while maintaining comparable sensitivity (94% vs. 97%, P = 1.00). For BI-RADS 3/4 lesions on breast MRI, PET/MR-TBR achieved an AUC of 0.90, with a significant NRI of 90.5% (P = 0.018) for BI-RADS 4 lesions. For breast lesions smaller than 10 mm, PET/MR-TBR increased specificity to 94% versus 75% for breast MRI (P > 0.05). For axillary lymph node evaluation, the quantitative PET/MR based on SUVmax (PET/MR-SUVmax) showed improved sensitivity (95% vs. 62%, P < 0.001) and a nonsignificant decrease in specificity (94% vs. 97%, P = 1.00) compared with breast MRI.
Conclusion:
[18F]FAPI PET/MR significantly improves diagnostic accuracy over breast MRI, particularly in reducing false positives and improving the detection of axillary lymph node metastases. This modality holds potential for refining breast cancer diagnostics, especially in challenging BI-RADS 4 lesions and improving more accurate staging for smaller lesions.
Insights
Fluorine-18-labeled fibroblast activation protein inhibitor 42 (¹⁸F]FAPI-42) PET/MR significantly enhances breast cancer diagnosis by reducing false positives and improving lymph node metastasis detection compared to standard breast MRI. This advanced imaging offers more accurate staging, particularly for challenging lesions.
Area of Science:
- Oncology
- Radiology
- Nuclear Medicine
- Medical Imaging
Background:
- Accurate diagnosis and staging of breast cancer are crucial for effective treatment planning.
- Limitations exist in current breast MRI diagnostic performance, particularly in differentiating benign from malignant lesions and assessing axillary lymph node involvement.
- Fibroblast activation protein (FAPI) targeted PET imaging shows promise for cancer detection due to FAP's overexpression in tumor-associated fibroblasts.
Purpose of the Study:
- To evaluate the diagnostic efficacy of fluorine-18-labeled fibroblast activation protein inhibitor 42 ([¹⁸F]FAPI-42) PET/MR compared to standard breast MRI.
- To assess the ability of [¹⁸F]FAPI-42 PET/MR in identifying primary breast lesions and detecting axillary lymph node metastases.
- To determine if integrated [¹⁸F]FAPI-42 PET/MR offers improved diagnostic accuracy, specificity, and sensitivity over breast MRI alone.
Main Methods:
- Prospective study of 64 women with BI-RADS 4 or 5 breast lesions.
- All participants underwent contrast-enhanced [¹⁸F]FAPI PET/MRI scans.
- Diagnostic performance was assessed using receiver operating characteristic (ROC) analysis and net reclassification improvement (NRI), with histology and follow-up as the gold standard.
Main Results:
- Integrated [¹⁸F]FAPI-42 PET/MR demonstrated superior specificity (96%) compared to breast MRI (68%) for primary breast lesions, significantly reducing false positives.
- For axillary lymph node evaluation, [¹⁸F]FAPI-42 PET/MR showed improved sensitivity (95%) versus breast MRI (62%).
- [¹⁸F]FAPI-42 PET/MR significantly improved diagnostic accuracy for BI-RADS 4 lesions and enhanced specificity for small lesions (<10 mm).
Conclusions:
- [¹⁸F]FAPI-42 PET/MR significantly enhances diagnostic accuracy in breast cancer detection and staging compared to conventional breast MRI.
- This modality excels in reducing false-positive findings and improving the detection of axillary lymph node metastases.
- [¹⁸F]FAPI-42 PET/MR shows considerable potential for refining breast cancer diagnostics, especially for BI-RADS 4 lesions and small tumors.
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