Detecting Amyloid Goiter With 99mTc-PYP SPECT/CT in the Setting of Ankylosing Spondylitis: An Uncommon Involvement of AA Amyloidosis.

ABSTRACT: We present a case with systemic amyloidosis secondary to ankylosing spondylitis (AA amyloidosis), whose 99mTc PYP scintigraphy revealed amyloid deposition in the thyroid gland (amyloid goiter). Amyloidosis is characterized by extracellular accumulation of amyloid fibril proteins leading to organ malfunction. Even though AA amyloidosis can be observed in patients with systemic inflammatory diseases, it is a very rare complication in ankylosing spondylitis. SPECT/CT images showed diffuse tracer uptake in enlarged thyroid gland containing fat density areas.

Targeted axillary dissection reduces residual nodal disease in clinically node- positive breast cancer after neoadjuvant chemotherapy.

BACKGROUND: Any advantage of performing targeted axillary dissection (TAD) compared to sentinel lymph node (SLN) biopsy (SLNB) is under debate in clinically node-positive (cN+) patients diagnosed with breast cancer. Our objective was to assess the feasibility of the removal of the clipped node (RCN) with TAD or without imaging-guided localisation by SLNB to reduce the residual axillary disease in completion axillary lymph node dissection (cALND) in cN+ breast cancer. METHODS: A combined analysis of two prospective cohorts, including 253 patients who underwent SLNB with/without TAD and with/without ALND following NAC, was performed. Finally, 222 patients (cT1-3N1/ycN0M0) with a clipped lymph node that was radiologically visible were analyzed. RESULTS: Overall, the clipped node was successfully identified in 246 patients (97.2%) by imaging. Of 222 patients, the clipped lymph nodes were non-SLNs in 44 patients (19.8%). Of patients in cohort B (n=129) with TAD, the clipped node was successfully removed by preoperative image-guided localisation, or the clipped lymph node was removed as the SLN as detected on preoperative SPECT-CT. Among patients with ypSLN(+) (n=109), no significant difference was found in non-SLN positivity at cALND between patients with TAD and RCN (41.7% vs. 46.9%, p=0.581). In the subgroup with TAD with axillary lymph node dissection (ALND; n=60), however, patients with a lymph node (LN) ratio (LNR) less than 50% and one metastatic LN in the TAD specimen were found to have significantly decreased non-SLN positivity compared to others (27.6% vs. 54.8%, p=0.032, and 22.2% vs. 50%, p=0.046). CONCLUSIONS: TAD by imaging-guided localisation is feasible with excellent identification rates of the clipped node. This approach has also been found to reduce the additional non-SLN positivity rate to encourage omitting ALND in patients with a low metastatic burden undergoing TAD.

How accurate is 68Gallium-prostate specific membrane antigen positron emission tomography / computed tomography (68Ga-PSMA PET/CT) on primary lymph node staging before radical prostatectomy in intermediate and high risk prostate cancer? A study of patient- and lymph node- based analyses.

BACKGROUND AND AIM: Gallium-68 (68Ga)-Prostate Membrane Specific Antigen Positron Emission Tomography/Computed Tomography (68Ga-PSMA PET/CT) is an emerging diagnostic modality which is gaining importance in individualized prostate cancer (PCa) management era. This study aimed to investigate the diagnostic accuracy of 68Ga-PSMA PET/CT on primary LN staging before radical prostatectomy (RP) in intermediate and high risk PCa. MATERIALS AND METHODS: The retrospectively documented 49 patients with intermediate and high risk non-metastatic PCa who had 68Ga-PSMA PET/CT before RP were enrolled into this study. The histopathology of dissected LNs was used as reference standard to evaluate the accuracy of 68Ga-PSMA PET/CT on primary LN staging, both in per-patient (n = 49) and in per-node (n = 454) analyses. The diagnostic accuracy was investigated using sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), and by area under the curve (AUC) provided using receiver operating curve (ROC) analysis. RESULTS: Median age was 64 (48-79) years and, median and mean PSA values were 10 (1.31-138) ng/ml and 16.2 (±19.8) ng/ml, respectively. 22 (44.9%) and 27 (55.1%) of patients had intermediate and high risk PCa, respectively. A total of 5 (10.2%) patients had histopathologically proven LN metastasis and 3 (60%) of them was detected in 68Ga-PSMA PET/CT. In per patient analysis, the sensitivity, specifity, PPV and NPV of 68Ga-PSMA PET/CT on primary LN staging were 0.60, 0.96, 0.60 and 0.96, respectively. Among overall 454 LNs, 16 (3.5 %) of them were reported as metastatic in histopathology and, 13 (2.9%) of these metastatic LNs were detected in 68Ga-PSMA PET/CT. In per-node analysis, the sensitivity, specificity, PPV and NPV of 68Ga-PSMA PET/CT on primary LN staging were 0.82, 0.99, 0.87 and 0.99, respectively. The ROC analyses found AUCs for primary LN staging as 0.777 (95%CI:0.508-1.0) in per patient analysis and, as 0.904 (95%CI:0.790 - 1.0) in per node analysis, respectively. CONCLUSION: The use of 68Ga-PSMA PET/CT has promising diagnostic accuracy on primary LN staging before RP in intermediate and high risk PCa. However, the efforts should be taken to increase sensitivity of 68Ga-PSMA PET/CT in individualized treatment era.

An Analysis for Therapeutic Doses of Patients with Neuroendocrine Tumor Treated with Lutetium 177 (177Lu)-DOTATATE.

Background: The aim of this study is to clarify the critical organs that limit treatment scheme and also evaluate the validity of currently used critical organ threshold values in neuroendocrine tumor (NET) patients, receiving peptide receptor radionuclide therapy (PRRT) with Lutetium 177 (177Lu)-DOTATATE. Materials and Methods: Thirty-six NET patients (ages 16-73 years) who received 177Lu-DOTATATE treatment were evaluated retrospectively in this study. Dosimetric calculations were made using medical internal radionuclide dose method. For calculation of organ doses, Internal Dose Assessment at Organ Level/Exponential Modelling 1.1 software program was used. Follow-up data were used to determine the organ failure. Results: A total of 141 cycles and mean of 3.91 (±1.33) cycles were applied to the patients. A mean of 691 mCi (±257 mCi) 177Lu-DOTATATE infusion in total and a dose between 70 and 200 mCi per treatment was applied to patients. Seven of 36 patients reached 23 Gy renal dose limit. In these patients, although kidney doses were between 23 and 29 Gy, there was no diminution in renal functions during follow-up. Two of 36 patients reached total bone marrow dose of 2 Gy limit. Bone marrow suppression did not develop in these patients. Conclusion: The critical organs that seem to affect the treatment scheme in PRRT with 177Lu-DOTATATE are kidney and bone marrow. Although there are established threshold levels, derived from radiotherapy experience, more studies are needed to clarify these dose limits in systemic radionuclide therapies such as PRRT.

225Ac-Prostate-Specific Membrane Antigen Therapy for Castration-Resistant Prostate Cancer: A Single-Center Experience.

PURPOSE: Prostate-specific membrane antigen (PSMA)-targeted therapies are among the current promising treatments. We present our preliminary results on the use of 225Ac-PSMA therapy in patients with metastatic castration-resistant prostate cancer as a single center. METHODS: Twelve advanced stage metastatic castration-resistant prostate cancer patients who received 225Ac-PSMA therapy were recruited in this retrospective study. Patients were treated with 225Ac-PSMA therapy every 8 weeks, and prostate-specific antigen (PSA) response was analyzed. Meanwhile, overall survival (OS) and progression-free survival (PFS) were estimated. Hematological and nonhematological adverse effects were recorded before and at 8 weeks after the last treatment cycle. RESULTS: In total, 25 cycles of 225Ac-PSMA were administered to 12 patients. The pretreatment median PSA level was 129 ng/mL. After the first cycle of therapy, any PSA response was observed in 9 of 12 patients, whereas 6 of them had biochemical response of >50%. Four of 12 patients reached the best PSA response after the first treatment cycle, whereas 3 patients after the second and 2 patients after the third cycle. The median PFS and OS were 4 and 10 months, respectively. For patients with any PSA response after the first cycle, OS was found to be higher despite without any statistical significance (10 vs 4 months; P = 0.301) when compared with the nonresponsive group. No significant difference was encountered in terms of adverse effect in the pretreatment and posttreatment era. CONCLUSIONS: Our preliminary results are encouraging, especially patients who had PSA response after the first cycle of 225Ac-PSMA therapy.

A rare case of ruptured liver metastases from a laryngeal cancer.

Rupture of a metastatic liver tumor associated with laryngeal cancer is a very rare complication with no previous case in the literature. We present a case of ruptured liver metastases which was treated conservatively. Dynamic contrast-enhanced computed tomography demonstrated active extravasation and discontinuity of liver capsule. When the patient came to our hospital from the external medical center, we did not see active extravasation on control computed tomography. This case highlights the role of radiologic imaging in the diagnosis and follow-up of ruptured hepatic metastases.

177Lu-PSMA Therapy in Metastatic Castration-Resistant Prostate Cancer.

The aim of this narrative review is to evaluate the current status of 177Lu-PSMA (prostate specific membrane antigen) therapy for metastatic castration-resistant prostate cancer (mCRPC) in the light of the current literature. We also addressed patient preparation, therapy administration and side effect profiles. 177Lu-PSMA therapy efficacy was assessed by using prospective trials, meta-analyses and major retrospective trials. Predictors of efficacy were also mentioned. Although there are some different approaches regarding the use of 177Lu-PSMA therapy in different countries, this type of therapy is generally safe, with a low toxicity profile. From the oncological point of view, a PSA (prostate specific antigen) decline of ≥50% was seen in 10.6-69% of patients with mCRPC; whereas progression-free survival (PFS) was reported to be 3-13.7 months in different studies. Consequently, 177Lu-PSMA therapy is a promising treatment in patients with mCRPC, with good clinical efficacy, even in heavily pretreated patients with multiple lines of systemic therapy. Currently, there are ongoing clinical trials in the United States, including a phase III multicenter FDA registration trial.

Metastatic Poorly Differentiated Thyroid Cancer With Heterogeneous Distribution of 18F-FDG, 68Ga-DOTATATE, and 68Ga-PSMA on PET/CT.

ABSTRACT: We present a case of a 55-year-old man with a history of poorly differentiated metastatic thyroid cancer, which is rare and shows aggressive behavior. The patient had radioactive iodine-negative multiple metastasis on 18F-FDG PET/CT, therefore 68Ga-DOTATATE and 68Ga-PSMA PET/CT were performed whether an opportunity exist for DOTATATE or PSMA-directed radionuclide therapy. Different patterns of tumoral uptakes were detected on 18F-FDG, 68Ga-DOTATATE, and 68Ga-PSMA PET/CT, as a demonstration of tumor heterogeneity.

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.

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.

Detection of Unusual Peritoneal Metastases of Prostate Cancer With 68Ga-Prostate-Specific Membrane Antigen PET/CT.

Peritoneal metastasis of prostate cancer (PC) is unusual site of metastatic disease; only limited case reports are published in literature. Ga-prostate-specific membrane antigen (PSMA) PET/CT is recently used for detection of PC metastasis with high accuracy rates. We present a case of a 68-year-old man with disseminated peritoneal metastases and abdominal metastatic lymph nodes of PC, demonstrated in Ga-PSMA PET/CT with intense PSMA uptake.

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.

68Ga-DOTATATE PET-CT imaging in carotid body paragangliomas.

OBJECTIVE: The aim of this study was to present our experience in the baseline evaluation of carotid body paragangliomas (CBP) with 68Ga-DOTATATE PET-CT. METHODS: Five patients (4F, 1M; age 24-73 years) with CBPs who underwent 68Ga-DOTATATE PET-CT scan before the treatment were evaluated retrospectively. PET-CT images were analyzed visually as well as semiquantitatively, with measurement of maximum standardized uptake value (SUVmax). RESULTS: All patients had unilateral CBP lesion, showed intense 68Ga-DOTATATE uptake in PET-CT. Additionally, 68Ga-DOTATATE avid lesions were found in two patients. One of them had focal intense uptake in thyroid gland and frontal cerebrum. The other one had intense uptake in bone and adrenal mass. Four patients were operated for unilateral primary CBP. Last patient was treated with peptide receptor radionuclide therapy (177Lu-DOTATATE) for both metastatic pheochromocytoma and CBP. CONCLUSIONS: 68Ga-DOTATATE PET-CT is a valuable imaging modality for staging of CBPs, detecting unknown lesions and changing the management of patients. It is also useful in demonstrating expression of SSTRs for PRRT opportunity.