Fibroblast activation protein inhibitor (FAPI) PET/CT shows excellent diagnostic accuracy for detecting lymph node metastases in lung cancer patients, according to a study published October 14 in Academic Radiology.
In a review of studies that included 409 patients, the technique was superior to standard-of-care FDG-PET/CT and could potentially serve as an alternative to invasive tissue sampling procedures, nuclear medicine researchers suggested.
“FAPI-PET/CT has a promising role for [lymph node] staging in lung cancer patients and may have the potential to be incorporated into the current diagnostic algorithm on preoperative mediastinal staging,” wrote lead author Qi-chang Wan, MD, of the China-Japan Union Hospital of Jilin University in Changchun, China.
FDG-PET/CT is widely used for lung cancer assessment and is considered to be accurate for the detection of lymph node (LN) metastases, yet diagnostic guidelines still advocate for invasive confirmatory tissue sampling procedures to achieve more accurate staging, the authors explained.
Conversely, FAPI-PET imaging, introduced in 2018, has shown in studies in small groups of patients to be highly accuracy for LN staging in lung cancer patients, they noted. Given its potential clinical impact, in this study, the researchers sought to provide a higher level of evidence to support its use.
The group identified seven studies published between 2022 and 2024 that reported the diagnostic accuracy of FAPI PET/CT in these cases, with six including a head-to-head comparison with FDG-PET/CT. Six studies were prospective, and one was retrospective. The researchers pooled and compared the sensitivity, specificity, and area under the receiver operating characteristics curve (AUC) for each technique.
According to the analysis, the pooled data on FAPI-PET/CT was significantly more accurate than that for FDG-PET/CT.
| FAPI-PET/CT vs. FDG-PET/CT for detecting LN metastases | ||
|---|---|---|
| FDG-PET/CT | FAPI-PET/CT | |
| Sensitivity | 78% | 89% |
| Specificity | 66% | 94% |
| AUC | 0.8 | 0.97 |
“FAPI PET/CT shows excellent diagnostic accuracy for the detection of LN metastases in lung cancer patients, and is superior to standard-of-care FDG PET/CT,” the group wrote.
Ultimately, the results may have a high clinical impact, as accurate pretherapeutic imaging-based assessment of thoracic LN metastases is essential for lung cancer treatment planning, the researchers suggested.
Ideally, FAPI-PET/CT could be used to resolve cases when there is doubt about positive FDG-PET/CT findings and to reduce the use of invasive procedures such as mediastinoscopy and endobronchial ultrasound-guided transbronchial needle aspiration, which carry a risk of procedure-related complications, they wrote.
Still, more studies will be required to determine whether FAPI PET/CT can replace FDG PET/CT, they added.
“[FAPI-PET/CT] holds the potential to optimize the need for invasive diagnostic procedures,” the group concluded.
The full study is available here.
