Semiconductor FDG PET/CT for Preoperative Identification of Grade 3 Invasive Nonmucinous Adenocarcinoma

To evaluate the diagnostic performance of semiconductor ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (sPET/CT) for identifying grade 3 invasive nonmucinous adenocarcinoma (INMA) and compare it with conventional FDG PET/CT (cPET/CT).

This retrospective single-center study included 664 patients who underwent resection for INMA between 2010 and 2024. Patients were assigned to sequential cPET/CT (n = 328) and sPET/CT (n = 336) cohorts according to the period of PET/CT acquisition. Receiver operating characteristic analysis was performed to determine optimal SUVmax cutoff values for predicting grade 3 INMA in the overall cohorts and 2 clinically relevant subgroups: clinical stage II or higher disease and tumors ≤2.0 cm without nodal or distant metastasis.

Grade 3 INMA accounted for 22.9% of cases in both cohorts. In the overall cohorts, cPET/CT showed an area under the curve (AUC) of 0.769, sensitivity of 0.840, and specificity of 0.589, whereas sPET/CT achieved an AUC of 0.860, sensitivity of 0.805, and specificity of 0.819. The AUCs were 0.661 versus 0.849 for clinical stage II or higher disease and 0.764 versus 0.950 for tumors ≤2.0 cm without nodal or distant metastasis. Formal comparison of the receiver operating characteristic curves showed that the AUC of sPET/CT was significantly higher than that of cPET/CT (P = .014).

In this sequential cohort study, sPET/CT demonstrated significantly better diagnostic performance than cPET/CT for predicting grade 3 INMA. Because the cohorts were sequential rather than randomized, these findings should be interpreted cautiously and require further validation.