Detection of metastases in newly diagnosed prostate cancer by using 68Ga-PSMA PET/CT and its relationship with modified D'Amico risk classification.

PURPOSE: We aimed to investigate the diagnostic power of 68Ga-PSMA PET/CT in the detection of metastatic spread of newly diagnosed PCa, and evaluate the relationship with modified D'Amico risk classification. METHODS: We evaluated newly diagnosed PCa patients who underwent 68Ga-PSMA PET/CT prior to therapy. All images were interpreted retrospectively and areas of abnormally increased tracer uptake were documented according to PSMA-RADS version 1.0 system. Patients were divided into risk groups as low, intermediate, or high risk, according to a modification in D'Amico classification system as ISUP grade 3 tumors were included to high-risk group. 68Ga-PSMA PET/CT findings were compared among risk groups as well as PSA levels, clinical T stages, and ISUP grades. RESULTS: A total of 356 patients were included to the study with a median PSA level was 16.42 (1.29-7013) ng/ml and median Gleason score was 8 (range: 6-10). Of these, 13(3.7%), 54 (15.1%), and 289 (81.2%) were in the low-, intermediate-, and high-risk groups, respectively. Lymph node metastases were detected in 125 (35.1%) patients, and in 48 of them, metastasis was limited to pelvic lymph nodes (PLN). Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated as 71.4%, 100%, 95.9%, 100%, and 95.4%, respectively for the detection of PLN, based on histopathological results of 49 patients. Overall, any metastasis was detected in 47.7% of high-risk patients, while only PLN metastases were defined in 3.7% intermediate-risk patients and none of low-risk patients had any kind of metastasis. CONCLUSION: This study revealed that 68Ga-PSMA PET/CT should be routinely used in newly diagnosed high-risk PCa patients; whereas it seems to be of limited use for intermediate-risk group and useless for the low-risk group.

A Rare Case and Atypical Metastatic Regions, Pulmonary Giant Cell Carcinoma.

Sixty two years old man referred to our clinic due to suspicion of thymic mass. The hypermetabolic nodular lesion in the right lung upper lobe was seen in 18F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) in addition to the mass in the anterior mediastinum which was found to without malignancy. The patient underwent wedge resection and final diagnosis was pulmonary giant cell carcinoma. In follow-up 18F-FDG PET/CT multiple lesions with pathological activity were observed in the cerebrum, right postauricular region, bilateral adrenal, stomach, pancreas, pelvic soft tissue, mesenteric, left femur and bilateral lung parenchyma 6 months after. The pathology results of the right frontal, pelvic mass and the postauricular region were metastasis.

Somatostatin receptor-positive breast lesions on 68Ga-DOTATATE PET/CT.

OBJECTIVE: This study sets out to evaluate patients with increased uptake in breast lesions on 68Ga-DOTATATE PET/CT (DOTA PET) and determine the clinical significance of somatostatin receptor (SSTR) positive breast lesions. METHODS: We retrospectively evaluated all patients with increased SSTR uptake in breast lesions on DOTA PET. Patients with physiological (e.g., lactation) or normal variant breast uptake (e.g., mild diffuse glandular uptake) were excluded. The maximum standard uptake value (SUVmax) was calculated using a manually drawn region of interest in the most intense uptake of breast lesions. All lesions were correlated with breast imaging, including mammography and ultrasonography. Histopathological correlation was performed if the lesion was suspicious for malignancy. Lesions were followed up radiologically (1-8 years). RESULTS: Out of 1573 retrospectively analyzed DOTA PET scans, the incidence of SSTR + breast lesions was measured as 1.1% (n = 18); however, 4 of 18 patients were excluded due to the lack of final diagnosis of lesions. The median age was 35 (range 14-58 years), and all patients were female. The median SUVmax of SSTR + breast lesions was 5.2 (range 1.5-12.6) for a total of 14 patients. Twelve patients had a single SSTR + breast lesion, while 2 patients had multiple SSTR + lesions on bilateral breasts. In 6 patients, single SSTR + lesions were considered as fibroadenoma; in 2 patients, multiple SSTR + lesions were considered as metastases of NET, based on correlative breast imaging. In 6 patients, histopathological confirmation was needed for the final diagnosis. Histopathologic findings confirmed fibroadenoma in 4 patients by biopsy, in 1 patient with surgical removal of the lesion. The last patient who had a history of IDC was diagnosed with a recurrence of IDC with biopsy. The median SUVmax was 5.1 (range 1.5-9.4) for malignant breast lesions and 5.4 (range 2.2-12.6) for benign breast lesions. CONCLUSION: SSTR + breast lesions on DOTA PET are rarely seen in clinical practice. Uptakes of breast lesions in our cases were variable and not useful for differential diagnosis of lesions. It seems that SSTR + breast lesions should be evaluated with clinical and radiological characteristics, and correlative breast imaging and/or histopathological verification should be performed for suspicious lesions to avoid misdiagnosis.

Does bone scintigraphy still have a role in the era of 68 Ga-PSMA PET/CT in prostate cancer?

OBJECTION: We aimed to evaluate the role of bone scintigraphy (BS) which has long been the imaging modality of choice in prostate cancer (PCa) and performed a head-to-head comparison between BS, BS + SPECT/CT and 68 Ga-PSMA-PET/CT, for the detection of bone metastasis of PCa. METHODS: We evaluated 138 PCa patients who underwent BS and 68 Ga-PSMA PET/CT and SPECT/CT of 102 of 138 patients. Images were interpreted retrospectively and areas of abnormally increased tracer uptake related to PCa were documented as benign, metastatic or equivocal. Equivocal uptakes were finally diagnosed based on a consensus review of correlative imaging. Patient- and lesion-based analysis was performed. Patients with superscan images were excluded from lesion-based analysis. RESULTS: At least one metastatic or equivocal uptake in skeleton was defined in 76 of 138 (55%) BS, in 33 of 102 (32.3%) SPECT/CT, and in 49 of 138 (35.5%) 68 Ga-PSMA PET/CT. 23 (16.7%) patients had also superscan findings on BS and 68 Ga-PSMA PET/CT. For patient-based analysis, sensitivity, specificity, accuracy, PPV, and NPV were calculated as 91.1%, 64.5%, 73.1%, 55.4% and 93.7% for BS; 95.5%, 82.7%, 86.9%, 72.8% and 96.2% for BS + SPECT/CT; 97.7%, 95.7%, 95.6%, 91.6% and 98.8% for 68 Ga-PSMA PET/CT. For lesion-based analysis, sensitivity, specificity, accuracy, PPV, and NPV were 53%, 63.9%, 60.1%, 42.8% and 71.8% for BS; 59.2%, 87.6%, 77.7%, 62.6% and 80% for BS + SPECT/CT; 96.4%, 98.1%, 97.5%, 96.4% and 98.1% for 68 Ga-PSMA PET/CT. CONCLUSION: This study has shown that 68 Ga-PSMA PET/CT overcomes the limitations of BS and proves superiority in detecting bone metastases, even in patients with SPECT/CT. Our findings present important implications that 68 Ga-PSMA PET/CT can replace BS in future practice.

Y90 selective internal radiation therapy and peptide receptor radionuclide therapy for the treatment of metastatic neuroendocrine tumors: combination or not?

BACKGROUND: Peptide receptor radionuclide therapy and selective internal radiation therapy are effective radionuclide therapy modalities for unresectable metastatic neuroendocrine tumor patients that cannot be controlled with somatostatin analogs. The present study is intended to evaluate the therapeutic efficacy and toxicity of the combined therapy of selective internal radiation therapy and peptide receptor radionuclide therapy and stand-alone selective internal radiation therapy in patients with neuroendocrine tumor, a liver-dominant disease. METHODS: This cohort consists of 27 patients with metastatic neuroendocrine tumor and liver-dominant disease. They were grouped as the patients who were treated with selective internal radiation therapy for unresectable liver metastasis (n = 15) and the patients who received a combination of selective internal radiation therapy and peptide receptor radionuclide therapy (n = 12) for hepatic and extrahepatic metastasis. Treatment efficacy and treatment-associated toxicity were retrospectively assessed in both groups. RESULTS: The objective treatment response and stable disease were found in 13 patients (86.6%) in the selective internal radiation therapy group and eight patients (66.6%) in the selective internal radiation therapy + peptide receptor radionuclide therapy group. The median overall survival rate was found to be 34.9 months, in the selective internal radiation therapy group and 67.5 months in the selective internal radiation therapy + peptide receptor radionuclide therapy group (P = 0.217). The median progression-free survival data was not reached, and the mean values of progression-free survival were 53.1 ± 9.9 months in the selective internal radiation therapy group, and 27.2 ± 5.9 months in the selective internal radiation therapy + peptide receptor radionuclide therapy group (P = 0.561). Temporary lymphopenia was the most common side effect. Grade 1-2 hepatotoxicity was observed to be 6.6% in the selective internal radiation therapy group, while it was not observed in selective internal radiation therapy + peptide receptor radionuclide therapy group. CONCLUSIONS: In the neuroendocrine tumors with liver-dominant metastatic disease, personalized selective internal radiation therapy and peptide receptor radionuclide therapy and their combinations result in increased survival rates. Selective internal radiation therapy alone could be an effective treatment in patients with liver-limited and -dominant disease.

Clinical Impact of Lower-Limb Imaging in 68Ga-PSMA PET/CT for Patients with Prostate Cancer.

Our purpose was to determine whether there is a clinical benefit to add lower-limb imaging in 68Ga-labeled prostate-specific membrane antigen (PSMA) PET/CT scans for patients with prostate cancer. Methods: In total, 701 patients with prostate cancer who underwent 68Ga-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 68Ga-PSMA PET/CT findings. Results: In 601 patients (85.7%), at least 1 tumoral lesion was observed on 68Ga-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 68Ga-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 (χ2 = 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.