Purpose: To evaluate parameters derived from 68Ga-PSMA-11 PET/CT images for discriminating pathological characteristics in primary clear-cell renal cell carcinoma (ccRCC).
Methods: The study retrospectively examined data for 36 ccRCC patients with preoperative 68Ga-PSMA-11 PET/CT scan and surgical specimens. Radiological parameters including maximal tumor diameter, mean CT value, and maximal standard uptake value (SUVmax) were derived from PET/CT images. Pathological characteristics included WHO/ISUP grade and adverse pathology (tumor necrosis or sarcomatoid or rhabdoid feature). Values of radiological parameters were compared within subgroups of pathological characteristics. Receiver operating characteristic (ROC) curve analysis was used for the effectiveness of radiological parameters in differentiating pathological characteristics, estimating area under the ROC curve (AUC) and 95% confidence intervals (CIs).
Results: The WHO/ISUP grade distribution for 36 tumors was grade 1, 9 (25.0%); grade 2, 12 (33.3%); grade 3, 9 (25.0%); and grade 4, 6 (16.7%). Adverse pathology was positive for 15 (41.7%). Radiological tumor diameter and SUVmax significantly differed by WHO/ISUP grade, pT stage, and adverse pathology (all P < 0.05), with no difference by CT value. Tumor diameter demonstrated sensitivity 86% and specificity 88% for pT stage, with cutoff 6.70 and AUC 0.91 (95% CI, 0.79-1.00, P < 0.001). SUVmax could effectively differentiate WHO/ISUP grade (3-4 vs. 1-2) and adverse pathology (positive vs. negative), with AUC 0.89 (95% CI, 0.81-0.98, P < 0.001), cutoff 16.4, sensitivity 100%, and specificity 71% and AUC 0.92 (95% CI, 0.85-0.99, P < 0.001), cutoff 18.5, sensitivity 94%, and specificity 87%, respectively.
Conclusion: 68Ga-PSMA-11 PET/CT could effectively identify aggressive pathological features of ccRCC.
Keywords: 68Ga-PSMA-11 PET/CT; Adverse pathology; Clear-cell renal cell carcinoma; WHO/ISUP grade.