Prediction of clinically significant prostate cancer by [68 Ga]Ga-PSMA-11 PET/CT: a potential tool for selecting patients for active surveillance

PURPOSE

In our study, our aim was to investigate the role of [68 Ga]Ga-PSMA-11 PET /CT imaging in the diagnosis of clinically significant prostate cancer (csPCa) (ISUP GG 2 and higher) in patients initially diagnosed with ISUP GG 1 and 2 after prostate biopsy.

MATERIALS AND METHODS

We retrospectively reviewed 147 patient records in whom [68 Ga]Ga-PSMA-11 PET/CT imaging was performed preoperatively. All patients were initially diagnosed with ISUP GG 1 and 2 PCa by biopsy. Final pathology reports were obtained after radical prostatectomy. The [68 Ga]Ga-PSMA-11 PET/CT images were evaluated to determine the PRIMARY score. Patients' mpMRI-PIRADS scores were also recorded when available and analyzed in correlation with the pathology results.

RESULTS

For the 114 patients scored using PRIMARY, 19 out of 37 patients with scores of 1 and 2 (51%) were diagnosed with csPCa. Of the 77 patients with PRIMARY scores between 3 and 5, 64 (83%) had csPCa. Notably, every patient with a PRIMARY score of 5 had csPCa. PRIMARY scoring had a sensitivity of 77% and specificity of 58%, with a positive predictive value of 83%. A moderate correlation was observed between PRIMARY scores and ISUP GG (Rho = 0.54, p < 0.001). In contrast, the PIRADS score displayed a sensitivity and specificity of 86% and 25% respectively, with a positive predictive value of 68%. No substantial correlation was found between PIRADS and ISUP GG. Statistical analysis revealed a significant correlation between PRIMARY and ISUP GG (p < 0.001), but not between PIRADS and ISUP GG (p = 0.281). Comparatively, PRIMARY scoring was significantly more reliable than PIRADS scoring in identifying csPCa.

CONCLUSION

[68 Ga]Ga-PSMA-11 PET/CT imaging is promising for distinguishing high-risk prostate cancer patients from those apt for active surveillance, potentially aiding in the identification of csPCa.

Evaluation of F-18 DOPA PET/CT in the detection of recurrent or metastatic medullary thyroid carcinoma: comparison with GA-68 DOTA-TATE PET/CT

OBJECTIVE

PET imaging with F-18 DOPA (FDOPA) and Ga-68 DOTATATE (TATE) shows the most promising results to detect medullary thyroid cancer (MTC) recurrence. We performed this comparative study to detect the site of recurrent or metastatic disease in MTC patients with elevated serum calcitonin (Ctn) and/or carcinoembryonic antigen (CEA) levels.

METHODS

We studied 46 MTC patients (25 women, 21 men) with elevated Ctn and/or CEA levels during follow-up who had both FDOPA and TATE PET/CT scans for re-staging purposes.

RESULTS

FDOPA PET imaging yielded an overall sensitivity of 86.8%, specificity of 100%, PPV of 100%, NPV of 61.5%, and accuracy of 89.1%, while TATE PET scan had the same values as 84.2%, 87.5%, 96.9%, 53.8%, and 84.6%, respectively, and there was no statistically significant difference between the two modalities with the exception of the specificity value that was higher for FDOPA imaging. In a subgroup of patients with overt Ctn or CEA elevation, sensitivity of FDOPA increased significantly, whereas TATE sensitivity did not change. FDOPA PET imaging was significantly superior in detecting liver and regional lymph node (LN) metastases, while TATE PET scan was significantly better in the skeletal metastases. Early FDOPA demonstrated 11 invisible lesions on late FDOPA.

CONCLUSION

Both FDOPA and TATE PET/CT imaging are useful to localize recurrences in MTC patients. While TATE imaging is superior to reveal skeletal disease, FDOPA seems better in liver and regional LN metastases; therefore, the two modalities appear complementary in monitoring MTC patients with elevated serum Ctn and/or CEA levels.

The Role of 68GA-PSMA PET/CT Scan In Patients with Prostate Adenocarcinoma who Underwent Radical Prostatectomy

PURPOSE

To determine whether a 68Ga-PSMA PET/CT scan evaluation before radical prostatectomy (RP) is an effective imaging modality for clinical local and lymph node (LN) staging compared with the pathological results.

MATERIALS AND METHODS

We performed a preoperative 68Ga-PSMA PET/CT scan in 51 patients with prostate cancer (PCa), who were scheduled for an RP operation between January 2014 and June 2016 in our clinic. The correlation between the RP pathology and the results of the 68Ga-PSMA PET/CT scan was investigated.

RESULTS

When the 68Ga-PSMA PET/CT scan results were evaluated according to the risk groups, intraprostatic activity was found in 5 of 12 patients (41.7%) in the low-risk group, 15 of 19 patients in the intermediate risk group (78.9%), and 90% patients in the high-risk group. The 68Ga-PSMA PET/CT scan sensitivity, specificity, positive and negative predictive values and accuracy were calculated as 58.2%, 75.3%, 84.4%, 44%, and 63%, respectively for intraprostatic tumor localization; 68.4%, 75%, 61.9%, 80%, and %72.6%, respectively for extracapsular extension; 63.6%, 92.3%, 70%, 90%, and 86%, respectively for seminal vesicle involvement; 50%, 100%, 100%, 88%, and 89.3%, respectively for LN metastasis.

CONCLUSION

The 68Ga-PSMA PET/CT scan accurately demonstrates intraprostatic tumor localization in high-risk group and presence of seminal vesicle involvement, which can help to accurately detect the target lesion before prostate biopsy. In addition, with its high sensitivity and specificity values, 68Ga-PSMA PET/CT is a valuable imaging method for the assessment of LN metastasis in intermediate- and high-risk groups and also provides accurate nodal staging before RP.