Search

Background: Imaging modalities are used to diagnose and clinical grading of clinically significant prostate cancer. In this study, 68Ga-PSMA PET/CT (PSMA) and multiparametric prostate MRI (mp-MRI) were compared in regard to locating intraprostatic tumor and locoregional staging., Methods: After ethics committee approval, a total of 49 patients with prostate cancer who had mp-MRI and PSMA before radical prostatectomy were included. Preoperative and postoperative PSA, transrectal ultrasound-guided prostate biopsy (TRUS-Bx) ISUP grade, radical prostatectomy ISUP grade, body mass index (BMI), TRUS prostate volume, mp-MRI tumor mapping, PSMAtumor mapping, pathologic tumor mapping, extraprostatic extension (EPE), seminal vesicle invasion (SVI), lymph node invasion (LNI), and bladder neck invasion (BNI)were retrospectively evaluated. Index tumor was located by uroradiologist, nuclear medicine specialist, and uropathologist on a 12-sector prostate pathology map and compared with each other in terms of accuracy and locoregional clinical staging., Results: Mean age of the patients was 66.18 ± 6.67 years and the mean of preoperative PSA results was 21.11 ± 32.56 ng/ml. Nearly half of the patients' (44.9%) pathology was reported as ISUP grade 4 and 5% and 18.4% of patients were surgical margin positive. According to the pathological findings, 362 out of 588 sectors were tumor-positive, 174 out of 362 sectors were tumor-positive in mp-MRI, and 175 out of 362 sectors were tumor-positive in PSMA. Both PSMA and mp-MRI were comparable (p = 0.823) and accurate to detect the location of the intraprostatic index tumor (AUC = 0.66 vs. 0.69 respectively, p = 0.82). The sensitivity and the specificity of the PSMA and mp-MRI for localizing intraprostatic index tumors were 42.5% versus 49.5% and 90.7% versus 88.6% respectively. mp-MRI was more accurate than PSMA in terms of EPE (AUC = 0.8 vs. AUC = 0.57 respectively, p = 0.027) and both methods were comparable in terms of SVI (AUC = 0.75 vs. AUC = 0.75, p = 0.886) and BNI (AUC = 0.51 vs. AUC = 0.59, p = 0.597). PSMA and mp-MRI were comparable in terms of LNI (AUC = 0.76 vs. AUC = 0.64, p = 0.39)., Conclusion: mp-MRI should be considered for its high accuracy in the diagnosis of EPE, especially before decision-making for nerve-sparing surgery in high-risk patients. Both imaging modalities were accurate for localizing intraprostatic index tumor. PSMA is accurate for detecting LNI., (© 2022 Wiley Periodicals LLC.)

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.

Our purpose was to determine whether there is a clinical benefit to add lower-limb imaging in 68 Ga-labeled prostate-specific membrane antigen (PSMA) PET/CT scans for patients with prostate cancer. Methods: In total, 701 patients with prostate cancer who underwent 68 Ga-PSMA PET/CT were evaluated retrospectively. All patients underwent additional lower-limb imaging. Images were reanalyzed by experienced nuclear medicine physicians, and metastatic sites were documented. The prostate-specific antigen (PSA) level and Gleason score were also compared with 68 Ga-PSMA PET/CT findings. Results: In 601 patients (85.7%), at least 1 tumoral lesion was observed on 68 Ga-PSMA PET/CT. The number of patients with bone metastasis in 2 forms was 278 patients (39.6%); 108 (15.4%) were oligometastatic (<4 metastases) and 170 (24.2%) were multimetastatic (≥4 metastases). In lower-limb imaging, bone metastasis was detected in 61 patients (8.7%), the specific locations of which were as follows: middle-distal femur ( n = 54), tibia ( n = 19), fibula ( n = 24), and calcaneus ( n = 1). Lower-limb metastasis was detected mostly in symptom-positive patients (70.1%) but in only 4% of the symptom-negative group. All patients with lower-extremity metastasis also had multiple bone metastases shown on limited whole-body 68 Ga-PSMA PET/CT. The median PSA level was significantly higher in multimetastatic patients with lower-limb metastasis than in those without lower-limb metastasis ( P < 0.001, Mann-Whitney U test), but no statistical differences was found in terms of Gleason score (χ 2 = 0.042, P = 0.837). According to receiver-operating-characteristic analysis, PSA has a good predictive value for detecting lower-limb metastasis, with 76.6% sensitivity and 72% specificity (using a reference cutoff PSA level of 24 ng/mL [area under the curve, 0.81; 95% confidence interval, 0.74-0.87]). Conclusion: Lower-limb imaging did not change the metastatic status of disease or significantly affect the therapeutic approach. However, if multimetastatic patients present relevant symptoms for lower-limb metastasis, it could be beneficial to consider including lower-limb imaging for possible palliative therapies., (© 2019 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: The intensity of prostate-specific membrane antigen (PSMA) expression increases as the tumor grade increases and the uptake of Ga-68-PSMA is higher in high-grade tumors. The aim of the present study was to evaluate the correlation of preoperative tracer uptake of primary tumor to Gleason Score in patients who underwent prostatectomy., Patients and Methods: We retrospectively evaluated 141 patients who had Ga-68-PSMA positron emission tomography/computed tomography (PET/CT) imaging and who underwent prostatectomy. All patients had a diagnosis of prostate cancer on the basis of 10-24 cores transrectal ultrasound-guided biopsy (TRUS-Bx). Histological assessment was performed according to the New Contemporary Prostate Cancer Grading System. All patients had a prostate-specific antigen (PSA) level measurement within maximum of 28 days before Ga-68-PSMA PET/CT. Region of interests were drawn manually around the prostate gland, avoiding the bladder activity, to calculate the maximum standardized uptake values (SUVmax) values., Results: The median PSA values for all patients were 10.0 ng/ml. PSA values for low-risk patients were significantly lower than those of high-risk patients (P<0.001). There were 41.1% upgrades and 7.8% downgrades following prostatectomy in terms of Grade Groups. According to the final pathology reports, 21% (n=16) of patients moved from a low-risk level (grade groups 1+2) to a high-risk level (grade groups 3+4+5). The median SUVmax value was 8.8, ranging from 2.1 to 62.4. There was a strong correlation between SUVmax values and grade groups (Pearson ρ=0.66) (P<0.001). The mean SUVmax values of high-risk patients were significantly higher than those of low-risk patients (18.9±12.1 vs. 7.16±6.2, respectively) (P<0.001). Receiver operation characteristic curve analysis of SUVmax at the cut-off value of 9.1 showed a high sensitivity (78%) and specificity (81%) for detection of high risk disease., Conclusion: SUVmax values correlate significantly with the grade groups of the primary tumor. The intraprostatic accumulation sites may predict clinically significant cancer and potentially serve as a target for biopsy sampling in conjunction with mpMRI in selected patients.

68Ga-PSMA-11 PET/CT has been proven to have high clinical value for imaging of prostate cancer and rapidly gained popularity. In this study, we aimed to investigate absorbed doses of 68Ga-PSMA-11. Seven patients (mean age = 66.9 ± 6.6 years, range: 57-79 years) were enrolled in the study. Whole body PET images were acquired with multiple time points. MIRD method, NUKFIT and OLINDA/EXM software were used for dosimetry calculations. Kidneys, bladder wall, salivary and lacrimal glands received the highest absorbed dose. Estimated absorbed doses to these organs after injection of 150 MBq 68Ga-PSMA-11 were 37.0, 12.6, 14.4 and 6.3 mSv, respectively. Effective dose from PET scanning with 150 MBq injected 68Ga-PSMA-11 was 2.5 mSv. In conclusion, 68Ga-PSMA-11 has a favorable dosimetry profile similar to the 68Ga labeled octreotide analogs, which are used safely in routine clinical practices for many years. No adverse effects were reported. The kidneys were the dose-limiting organs.

Ga-prostate-specific membrane antigen (PSMA) PET/CT is a rapidly evolving diagnostic technique to image prostate cancer. In contrast to the name PSMA, various tissues show Ga-PSMA uptake in PET/CT imaging. We present a case of a 68-year-old man with prostate cancer who underwent Ga-PSMA PET/CT. Along with metastatic lymph nodes, multiple nodular lesions within the peritoneal spaces of all 4 quadrants of the abdomen showed high PSMA expression. Because of a history of splenic rupture, a Tc-labeled heat-denatured erythrocyte scintigraphy and SPECT were performed. Peritoneal lesions showed high uptake, confirming widespread peritoneal splenosis.

Purpose: To assess the diagnostic accuracy of 68 Ga-PSMA PET in predicting lymph node (LN) metastases in primary N staging in high-risk and very high-risk nonmetastatic prostate cancer in comparison with morphological imaging., Methods: This was a multicentre trial of the Society of Urologic Oncology in Turkey in conjunction with the Nuclear Medicine Department of Cerrahpasa School of Medicine, Istanbul University. Patients were accrued from eight centres. Patients with high-risk and very high-risk disease scheduled to undergo surgical treatment with extended LN dissection between July 2014 and October 2015 were included. Either MRI or CT was used for morphological imaging. PSMA PET/CT was performed and evaluated at a single centre. Sensitivity, specificity and accuracy were calculated for the detection of lymphatic metastases by PSMA PET/CT and morphological imaging. Kappa values were calculated to evaluate the correlation between the numbers of LN metastases detected by PSMA PET/CT and by histopathology., Results: Data on 51 eligible patients are presented. The sensitivity, specificity and accuracy of PSMA PET in detecting LN metastases in the primary setting were 53%, 86% and 76%, and increased to 67%, 88% and 81% in the subgroup with of patients with ≥15 LN removed. Kappa values for the correlation between imaging and pathology were 0.41 for PSMA PET and 0.18 for morphological imaging., Conclusions: PSMA PET/CT is superior to morphological imaging for the detection of metastatic LNs in patients with primary prostate cancer. Surgical dissection remains the gold standard for precise lymphatic staging.

Introduction: Prostate-specific membrane antigen (PSMA) is increasingly being recognized as a novel target for the PET imaging of prostate cancer (PCa) and Ga-DKFZ-11 (Ga-PSMA) has been suggested as a novel tracer for detection of PCa relapses and metastases. The aim of this study was to evaluate the diagnostic value of PSMA PET/CT in the diagnosis of recurrent PCa with low prostate-specific antigen (PSA) levels., Patients and Methods: We carried out a retrospective analysis of patients who underwent PSMA PET/CT from November 2013 to December 2014 in our department. Among these patients, 50 out of 178 who had increasing PSA levels (<5 ng/ml) and did not have known metastasis were included in this study., Results: Patients had an average PSA of 1.41 ng/ml. A total of 29 patients (58%) showed at least one positive lesion. PET positivity rates of 31% (n=4), 54% (n=13), and 88% (n=14) were observed in patients with a PSA level of less than 0.2, 0.2-2, and 2-5 ng/ml, respectively. A positive correlation was observed between positivity rate and Gleason scores and blood PSA levels. Verification was performed in 46 patients, with biopsy (n=3) and follow-up, and conventional imaging studies at the time of the PET/CT or during follow-up with a mean period of 10.6±3.3 months and ranged from 3.8 to 16.4 months. According to patient-based analysis of 46 cases, 57% of patients had true positive, 24% of patients had true negative, 2% of patients had false positive, an 18% of patients had false-negative findings. A sensitivity of 76.47% (95% confidence interval: 58.83-89.25%) and a specificity of 91.67% (95% confidence interval: 61.52-99.79%) were found., Conclusion: PET/CT with Ga-PSMA is a valuable tool for assessing recurrence of PCa with a high sensitivity in patients who have PSA levels between 0.2 and 5 ng/ml. In addition, this study suggests that PSMA PET/CT can be used in patients with very low (<0.2 ng/ml) but increasing PSA levels, which, in many cases, may influence further clinical management.

Purpose: Ga-PSMA-11 is a novel PET tracer suggested to be used for imaging of advanced prostate cancer. In this study, we aimed to present a detailed biodistribution of Ga-PSMA-11, including physiological and benign variants of prostate-specific membrane antigen (PSMA) imaging., Materials and Methods: We carried out a retrospective analysis of 40 patients who underwent PSMA PET/computed tomography (CT) imaging and who had no evidence of residual or metastatic disease on the scans. In addition, 16 patients who underwent PSMA PET/CT imaging with any indication other than prostate cancer were included in the study to evaluate physiological uptake in the normal prostate gland. The median, minimum-maximum, and mean standardized uptake value (SUV) values were calculated for visceral organs, bone marrow and lymph nodes, and mucosal areas. Any physiological variants or benign lesions with Ga-PSMA-11 were also noted., Results: Ga-PSMA-11 uptake was noted in the kidneys, parotid and submandibular glands, duodenum, small intestines, spleen, liver, and lacrimal glands, and mucosal uptake in the nasopharynx, vocal cords, pancreas, stomach, mediastinal blood pool, thyroid gland, adrenal gland, rectum, vertebral bone marrow, and testes. Celiac ganglia showed slight Ga-PSMA-11 uptake in 24 of 40 patients without the presence of any other pathologic lymph nodes in abdominal and pelvic areas. Variable uptake of Ga-PSMA-11 was observed in calcified choroid plexus, a thyroid nodule, an adrenal nodule, axillary lymph nodes and celiac ganglia, occasional osteophytes, and gallbladder. The patient group with PSMA PET/CT for indications other than prostate cancer (n=16) showed a slight radiotracer uptake in normal prostate gland (SUVmax: 5.5±1.6, range: 3.5-8.3)., Conclusion: This study shows normal distribution pattern, range of SUVs, and physiological variants of Ga-PSMA-11. In addition, several potential pitfalls were documented to prevent misinterpretations of the scan.

Purpose: The aim of the study was to evaluate the diagnostic value of the prostate-specific membrane antigen (PSMA) ligand (68)Ga-HBED-CC (PSMA PET/CT) in patients with prostate cancer and evaluate the value of early imaging of the pelvis., Materials and Methods: The files of 28 patients were retrospectively evaluated. All patients had a histopatological confirmation of prostate cancer. PSMA PET/CT images were obtained at 5 and 60 min after injection from all patients., Results: Intense pathologic radiotracer uptake was observed in 23 patients (77%) at the site of primary tumour. Lymph node metastases were detected in 10 patients (36%) and bone metastases were detected in seven patients (25%). Bone scan (n=25) results revealed metastatic bone lesions in four patients, equivocal results in nine patients and normal results in 12 patients. PSMA PET/CT confirmed bone metastases in all four patients. Pathologic radiotracer uptake in PSMA PET/CT scans was observed only in one patient among those who had equivocal bone scans. PSMA PET/CT showed additional bone lesions in two patients who had a normal bone scan. When we compared early and late pelvic images we found no difference in the number of lesions detected. The maximum standardized uptake value (SUV(max)) for primary tumour, lymph nodes and bone metastases was significantly higher in late images., Conclusion: PSMA PET/CT imaging seems to be a valuable imaging modality for evaluation of primary prostate cancer and it seems to have potential for the detection of lymph node and bone metastases. Early images 5 min p.i. can help to better distinguish between urinary bladder (before tracer accumulation occurs) and tumour lesions.