Different detection rates of brain metastasis in different pathological types of lung cancer by ¹⁸F-FAPI PET/CT

The purpose of this study was to evaluate the utility of fluorine-18-fibroblast activation protein inhibitor (¹⁸F-FAPI) PET/CT for detecting brain metastasis (BM) in different pathological types of lung cancer using craniocerebral MRI as the standard.

From December 2020 to October 2021, patients with pathologically confirmed lung cancer and suspected BM were prospectively enrolled and underwent paired ¹⁸F-FAPI PET/CT and MRI. The number of BMs and maximum tumor diameter were measured by MRI. The maximum and peak standardized uptake values (SUVmax and SUVpeak, respectively) and tumor-to-background ratio (TBR) on ¹⁸F-FAPI PET/CT in BMs were evaluated.

A total of 76 BM lesions from 18 patients (11 males and 7 females) were evaluated. Among these, 23 lesions were detected by ¹⁸F-FAPI PET/CT. The detection rate of BM in adenocarcinoma was 48.28%, which was significantly higher than that in large cell carcinoma (16.67%, P = 0.016) and small cell carcinoma (0%, P = 0.009), but showed no significant difference from that in squamous carcinoma (35.71%, P = 0.437). The detection rate in squamous carcinoma was significantly higher than that in small cell carcinoma (P = 0.043), while no significant differences were observed between large cell carcinoma and small cell carcinoma (P = 0.183), or between large cell carcinoma and squamous carcinoma (P = 0.191).

This study revealed differences in the detection rates of BM in lung cancer types by ¹⁸F-FAPI PET/CT, with the highest and lowest detection rates in adenocarcinoma and small cell carcinoma, respectively, which may be valuable for predicting the prognosis of lung cancer patients with BM.

Institutional review board approval NO. SDZLEC2021-112-02.