FAPI-PET imaging may enhance detection of lepidic subtype lung cancer, reveals study

A recent study introduced a new diagnostic imaging technique that could significantly improve the detection of certain lung cancer subtypes traditionally elusive to standard PET scans. This resaerch focused on the diagnostic capabilities of a novel PET imaging method using 68Ga-labeled fibroblast activation protein inhibitors (FAPIs) that could revolutionize how oncologists identify and treat lung cancers, particularly the lepidic subtype that often does not show up on conventional 18F-FDG PET scans. The key findings of the study were published in the Journal of Nuclear Medicine.

Lung cancer remains one of the most challenging malignancies to diagnose and treat, primarily because of its varied subtypes and the limitations of current imaging technologies. 18F-FDG PET often fails to detect lepidic lung cancer and to address this, Manuel Röhrich and team evaluated the effectiveness of 68Ga-FAPI-46 PET in detecting 18F-FDG–negative pulmonary lesions.

The study included 19 patients with suspected lung cancer and who underwent surgery or biopsy for a definitive histologic diagnosis after their PET scans. The research utilized FAP immunohistochemistry on tissue samples to corroborate the PET findings and to confirm the presence of FAP-positive cancer-associated fibroblasts predominantly in lepidic lung cancer.

During the clinical trials, both static and dynamic 68Ga-FAPI-46 PET scans were performed along with the standard 18F-FDG PET. The results showed that lung cancer lesions expressed significantly higher uptake of 68Ga-FAPI-46 which reflected in increased maximum and mean standardized uptake values (SUVmax and SUVmean) and tumor-to-background ratios (TBR) when compared to benign lesions. The dynamic imaging results differentiated lung cancer from non-cancerous lesions through distinct time-activity curve patterns. These patterns included an initial increase in activity typical of lung cancer that contrasted with the decreasing curves which were indicative of benign conditions.

The findings underline the superior sensitivity and specificity of 68Ga-FAPI-46 PET in distinguishing between malignant and benign pulmonary lesions in cases where 18F-FDG PET falls short. The introduction of 68Ga-FAPI-46 PET could thus lead to better patient stratification and more patient-specific treatment approaches by improving outcomes for the individuals with hard-to-diagnose subtypes of lung cancer.

Reference:

Röhrich, M., Daum, J., Gutjahr, E., Spektor, A.-M., Glatting, F. M., Sahin, Y. A., Buchholz, H. G., Hoppner, J., Schroeter, C., Mavriopoulou, E., Schlamp, K., Grott, M., Eichhorn, F., Heußel, C. P., Kauczor, H. U., Kreuter, M., Giesel, F., Schreckenberger, M., Winter, H., & Haberkorn, U. (2024). Diagnostic Potential of Supplemental Static and Dynamic68Ga-FAPI-46 PET for Primary18F-FDG–Negative Pulmonary Lesions. In Journal of Nuclear Medicine (p. jnumed.123.267103). Society of Nuclear Medicine. https://doi.org/10.2967/jnumed.123.267103