Correlation of Intraprostatic Tumor Extent with ⁶⁸Ga-PSMA Distribution in Patients with Prostate Cancer

Abstract

We evaluated the diagnostic value and accuracy of prostatespecific membrane antigen (PSMA) PET for the intraprostatic delineation of prostate cancer before prostatectomy. Methods: We identified 6 patients with biopsy-proven high-risk prostate cancer who were referred for 68 Ga-PSMA PET/CT before radical prostatectomy to rule out metastasis. After prostatectomy, a histologic map of the prostate was reconstructed. The histologic extent and Gleason score of each segment of the prostate were compared with 68 Ga-PSMA PET images resliced to the histologic axis. Sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratios were calculated. The SUV of each segment was measured, and median values were compared. Results: Of the 132 segments, 112 were eligible for analysis. The correlation of histologic results with 68 Ga-PSMA PET images showed a specificity and sensitivity of 92%. The positive and negative likelihood ratio and the positive and negative predictive value for detection of prostate cancer on 68 Ga-PSMA PET were 11.5, 0.09, 96%, and 85%, respectively. The median SUV max of true-positive prostate segments was significantly higher than that of true-negative segments (11.0 ± 7.8 vs. 2.7 ± 0.9, P , 0.001), and a cutoff of 4 revealed a sensitivity and specificity of 86.5% and an accuracy of 87.5%. Conclusion: These preliminary results show that the intraprostatic localization and extent of prostate cancer may be estimated by 68 Ga-PSMA PET. This imaging method may be helpful for identifying target lesions before prostate biopsy and may support decision making before focal or radical therapy.

PSMA Ligands for PET Imaging of Prostate Cancer

“…These studies demonstrated relatively similar results, with a significantly higher 68 Ga-PSMA-11 uptake in positive segments than in negative segments (SUV max of 11.8 vs. 4.9 and 11.0 vs. 2.7, respectively, P , 0.001 each) (50,51). Results from combining 68 Ga-PSMA-11 and multiparametric MRI on 53 preoperative intermediate-/high-risk patients indicated a potential for targeting biopsies.…”

“…With regard to intraprostatic tumor localization by 68 Ga-PSMA-11 PET/CT, imaging findings were correlated with histopathology using segment-or voxel-based approaches in several studies (50)(51)(52). These studies demonstrated relatively similar results, with a significantly higher 68 Ga-PSMA-11 uptake in positive segments than in negative segments (SUV max of 11.8 vs. 4.9 and 11.0 vs. 2.7, respectively, P , 0.001 each) (50,51).…”

Response and Tolerability of a Single Dose of177Lu-PSMA-617 in Patients with Metastatic Castration-Resistant Prostate Cancer: A Multicenter Retrospective Analysis

“…68 Ga-PSMA-11 PET/CT was performed before the therapy, using a previously described procedure (3,5), to demonstrate PSMA-positive metastatic disease and adequate PSMA expression in tumor lesions. In accordance with clinical standards, renal scintigraphy was also performed before the therapy, using a previously described procedure (10,11), to rule out obstructive disease and to evaluate kidney function.…”

“…In the last few years, there has been increasing evidence that PSMA imaging is valuable for diagnosis of recurrent and metastatic prostate cancer and, more recently, for preoperative staging of biopsy-proven prostate cancer patients to rule out distant metastases and evaluate the extent of intraprostatic disease (1)(2)(3)(4)(5).…”

German Multicenter Study Investigating177Lu-PSMA-617 Radioligand Therapy in Advanced Prostate Cancer Patients

“…Radiolabeled ligands targeting PSMA have recently been the subject of numerous studies showing high sensitivity and contrast in detecting recurrent prostate cancer and its metastases with remarkable detection rates (4)(5)(6)(7). Recent studies have also shown a high sensitivity of PSMA-targeted imaging in determining the local extent of disease before radical prostatectomy (8)(9)(10). The high PSMA expression in prostate cancer metastases makes it also a promising approach to develop new tracers for targeted radionuclide therapies.…”