A case of metastatic lymphoepithelial carcinoma of parotid gland identified on 68gallium DOTA-[Tyr3] octreotate PET CT.

The authors present the case of a 59-year-old lady diagnosed with lymphoepithelial carcinoma (LEC) of the left parotid gland. The primary tumour was identified using contrast-enhanced CT, and diagnosis was confirmed via fine needle aspiration cytology and immunohistochemistry. Staging using fluorine-18 fluorodeoxyglucose PET CT revealed regional nodal metastases, while no distant metastasis was evident. Following radical radiotherapy, a favourable locoregional response was observed on MRI, yet the patient's plasma Epstein-Barr virus load continued to rise. Given her primary tumour's somatostatin receptor type 2 (SSTR2) positivity, gallium-68 DOTA-[Tyr3] octreotate PET CT (68Ga-DOTATATE PET CT) was performed, revealing multiple distant metastases with DOTATATE avidity. Despite attempts at palliative chemotherapy and immunotherapy, disease progression led to the decision for the best supportive care. The unique presentation of metastatic LEC on 68Ga-DOTATATE PET CT suggests a potential role for SSTR2-targeted imaging in diagnosis and management.

68 Ga-DOTATATE PET/CT of Metastatic Lymphoepithelial Carcinoma of Parotid Gland.

ABSTRACT: We present a case of a 59-year-old woman with lymphoepithelial carcinoma of left parotid gland. She was treated with radical radiotherapy, but her plasma Epstein-Barr virus DNA load continued to increase despite good locoregional response. As her primary tumor was positive for somatostatin receptor type 2, we performed 68 Ga-DOTATATE PET/CT, which revealed multiple DOTATATE-avid distant metastases.

Selective Internal Radiation Therapy with Yttrium-90 Resin Microspheres Followed by Gemcitabine plus Cisplatin for Unresectable Intrahepatic Cholangiocarcinoma: A Phase 2 Single-Arm Multicenter Clinical Trial.

Introduction: This investigator-initiated clinical trial aims to study the efficacy and safety of administering selective internal radiation therapy with resin yttrium-90 microspheres (SIRT) followed by standard chemotherapy in unresectable intrahepatic cholangiocarcinoma (ICC). Methods: A phase 2 single-arm multicenter study was conducted in patients with unresectable ICC (NCT02167711). SIRT was administered at dose of 120 Gy targeted at tumor followed by commencement of gemcitabine 1,000 mg/m2 and cisplatin 25 mg/m2 on days one and eight of a 21-day cycle. The primary endpoint was overall survival (OS), and the secondary endpoints include progression-free survival (PFS), response rate according to Response Evaluation Criteria in solid tumors 1.1, toxicity, and time from SIRT to commencement of chemotherapy. Results: Total 31 patients were screened and twenty-four were recruited. All patients completed SIRT and 16 of them underwent subsequent chemotherapy. The median cycle of chemotherapy was 5 (range: 1-8). The median OS was 13.6 months (95% CI: 5.4-21.6) for the intent-to-treat population. Among 16 patients undergoing chemotherapy, the median OS was 21.6 months (95% CI: 7.3-25.2) and the median PFS was 9 months (95% CI: 3.2-13.1). The response rate was 25% (95% CI: 3.8-46.2%), and the disease control rate was 75% (95% CI: 53.8-96.2%). No new safety signal was observed, with fewer than 10% of patients suffering from grade 3 or higher treatment-related adverse events. The median time from SIRT to chemotherapy was 29 (range: 7-42) days. Eight patients could not receive chemotherapy due to rapid progressive disease (n = 4), underlying treatment unrelated comorbidities (n = 2), and withdrawal of consent due to personal reasons (n = 2). Conclusions: Treatment of SIRT followed by standard gemcitabine and cisplatin chemotherapy is feasible and effective for unresectable ICC. Further studies are required to study the optimal sequence of SIRT and chemotherapy.

PSMA PET Imaging and Therapy in Adenoid Cystic Carcinoma and Other Salivary Gland Cancers: A Systematic Review.

Adenoid cystic carcinoma (ACC) and other salivary gland cancers (SGCs) are rare tumors where application of prostate specific membrane antigen (PSMA) positron emission tomography (PET) and PSMA radioligand therapy have yet to be studied extensively. This review explores the role of PSMA PET imaging and therapy as a theranostic tool for ACC and other SGCs based on current literature. A comprehensive literature search on PubMed and Embase was performed. All relevant studies containing information on PSMA PET imaging in ACC and SGC were included. Ten studies (one prospective, three retrospective, five case reports and one review paper) were included. For ACC, the mean maximum standardized uptake value (SUVmax) for local recurrence and distant metastases ranged from 2.41 to 13.8 and 2.04 to 14.9, respectively. In SGC, the meanSUVmax ranged from 1.2-12.50. Most studies observed PSMA expression positivity on immunohistochemistry (IHC) when there was PSMA PET uptake. PSMA PET was able to detect lesions not detected on standard imaging. Despite the small number of studies and wide intra-patient and inter-tumor variation of PSMA uptake in ACC and SGC, 68Gallium (68Ga)-PSMA PET has promising prospects as a diagnostic and radioligand therapeutic option. Further studies to answer the various theranostics considerations are required to guide its use in the real-world setting.

Anastomosing Hemangioma on 68Ga-DOTATATE PET/CT: A Potential Pitfall.

ABSTRACT: Anastomosing hemangioma (AH) is a rare benign vascular lesion that primarily involves the genitourinary tract. Cases have also rarely been reported in other organs. AH is often discovered incidentally and resembles angiosarcoma histologically. On imaging, it may mimic other vascular lesions such as renal cell carcinoma and neuroendocrine tumors. We present a case of a 32-year-old woman with incidentally detected AH involving the kidneys, adrenal glands, liver, and retroperitoneum, initially presumed to be neuroendocrine tumors based on imaging findings on CT and 68Ga-DOTATATE PET scans.

Expect the Unexpected: Artifacts From Lodged 124I Capsule in Esophagus on PET/CT.

ABSTRACT: A 61-year-old woman with well-differentiated thyroid cancer underwent 124I-PET/CT imaging. A 124I capsule was administered orally, and the patient was imaged 90 minutes after from the skull vertex to feet. The 124I capsule was unexpectedly lodged in the esophagus. We illustrate attenuation and scatter correction artifacts from 124I capsule unexpectedly lodged in the esophagus and the usefulness of nonattenuation correction images in such circumstances. This also highlights the importance of drinking adequate amounts of water following the ingestion of iodine capsules (123I, 124I, or 131I) to reduce the resulting radiation dose to the esophagus.

A Multiplex Thyroid-Specific Assay for Quantification of Circulating Thyroid Cell-Free RNA in Plasma of Thyroid Cancer Patients.

BACKGROUND: The standard of care for thyroid cancer management is thyroidectomy and adjuvant radioactive iodine (RAI). There is a paucity of clinical tool that quantifies residual thyroid volume reliably for precise adjuvant RAI dosing. Serum thyroglobulin (TG), tumour marker for thyroid cancer, takes 4 weeks for complete clearance due to its long half-life, and might be undetectable in 12% of structural disease patients. It detects recurrence with a sensitivity of 19-40%, mainly attributed to issue of TG antibody interference with TG immunometric assay. We hypothesise that the quantity of thyroid-specific cell-free RNA (cfRNA) is indicative of amount of thyroid tissues, and that during thyroid surgery, cfRNA levels decrease accordingly. METHODS: We identified 11 biologically significant and highly expressed thyroid-specific targets from Human Protein Atlas and literature. To assess for a fall in thyroid-specific cfRNA level, we recruited 16 patients undergoing thyroid surgery or RAI for malignant or benign thyroid disease, and tracked longitudinal trend of cfRNA. To assess the utility of cfRNA in detecting metastatic thyroid cancer, cfRNA of 11 patients at intermediate to high risk of recurrence was measured during surveillance and at time of clinical recurrence. RESULTS: The multiplex assay was capable of amplifying and quantifying multiple thyroid-specific genes in a single reaction. The selected targets were amplified successfully from RNA extracted directly from the thyroid (positive control), indicating that they were highly expressed within thyroid tissue. These cfRNAs were present in plasma, in amounts quantifiable using qRT-PCR. Four cfRNA transcripts (TPO, GFRA2, IVD, TG) fell post-treatment in more than 50% of cohort. The thyroid peroxidase (TPO) cfRNA fell post-therapy in 63% of cohort by 80%, as early as 1 day post-treatment, supporting the potential role as early indicator of remnant thyroid tissue volume. We demonstrated the clinical relevance of circulating TPO cfRNA by tracking temporal changes in setting of peri-treatment, recurrence, and TG Ab positive state. CONCLUSION: Using a multiplex pre-amplification approach, the TPO cfRNA was a potential biomarker that can track residual thyroid mass. It can be further optimised for quantification of thyroid volume to guide RAI doses and for detection of thyroid cancer recurrence.

Real-World Data on Clinical Outcomes of Patients with Liver Cancer: A Prospective Validation of the National Cancer Centre Singapore Consensus Guidelines for the Management of Hepatocellular Carcinoma.

INTRODUCTION: Real-world management of patients with hepatocellular carcinoma (HCC) is crucially challenging in the current rapidly evolving clinical environment which includes the need for respecting patient preferences and autonomy. In this context, regional/national treatment guidelines nuanced to local demographics have increasing importance in guiding disease management. We report here real-world data on clinical outcomes in HCC from a validation of the Consensus Guidelines for HCC at the National Cancer Centre Singapore (NCCS). METHOD: We evaluated the NCCS guidelines using prospectively collected real-world data, comparing the efficacy of treatment received using overall survival (OS) and progression-free survival (PFS). Treatment outcomes were also independently evaluated against 2 external sets of guidelines, the Barcelona Clinic Liver Cancer (BCLC) and Hong Kong Liver Cancer (HKLC). RESULTS: Overall treatment compliance to the NCCS guidelines was 79.2%. Superior median OS was observed in patients receiving treatment compliant with NCCS guidelines for early (nonestimable vs. 23.5 months p < 0.0001), locally advanced (28.1 vs. 22.2 months p = 0.0216) and locally advanced with macrovascular invasion (10.3 vs. 3.3 months p = 0.0013) but not for metastatic HCC (8.1 vs. 6.8 months p = 0.6300), but PFS was similar. Better clinical outcomes were seen in BCLC C patients who received treatment compliant with NCCS guidelines than in patients with treatment only allowed by BCLC guidelines (median OS 14.2 vs. 7.4 months p = 0.0002; median PFS 6.1 vs. 4.0 months p = 0.0286). Clinical outcomes were, however, similar for patients across all HKLC stages receiving NCCS-recommended treatment regardless of whether their treatment was allowed by HKLC. CONCLUSION: The high overall compliance rate and satisfactory clinical outcomes of patients managed according to the NCCS guidelines confirm its validity. This validation using real-world data considers patient and treating clinician preferences, thus providing a realistic analysis of the usefulness of the NCCS guidelines when applied in the clinics.

Paraneoplastic Secretion of Multiple Phosphatonins From a Deep Fibrous Histiocytoma Causing Oncogenic Osteomalacia.

CONTEXT: Literature suggests that oncogenic osteomalacia is usually caused by a benign mesenchymal tumor secreting fibroblast growth factor subtype-23 (FGF-23), but the involvement of other phosphatonins has only been scarcely reported. We have previously published a seemingly typical case of oncogenic osteomalacia. Following curative neoplasm resection, we now report unique molecular characteristics and biology of this tumor. CASE DESCRIPTION: A 25-year-old man had been diagnosed with severe oncogenic osteomalacia that gradually crippled him over 6 years. 68Ga-DOTA-TATE positron emission tomography/computed tomography scan localized the culprit tumor to his left sole, which on resection revealed a deep fibrous histiocytoma displaying a proliferation of spindle cells with storiform pattern associated with multinucleated giant cells resembling osteoclasts. Circulating FGF-23, which was elevated more than 2-fold, declined to undetectable levels 24 h after surgery. Microarray analysis revealed increased tumor gene expression of the phosphatonins FGF-23, matrix extracellular phosphoglycoprotein (MEPE) and secreted frizzled-related protein subtype 4, with elevated levels of all 3 proteins confirmed through immunoblot analysis. Differential expression of genes involved in bone formation and bone mineralization were further identified. The patient made an astonishing recovery from being wheelchair bound to fully self-ambulant 2 months postoperatively. CONCLUSION: This report describes oncogenic osteomalacia due to a deep fibrous histiocytoma, which coincidentally has been found to induce profound muscle weakness via the overexpression of 3 phosphatonins, which resolved fully upon radical resection of the tumor. Additionally, genes involved in bone formation and bone remodeling contribute to the molecular signature of oncogenic osteomalacia.

Frequent neck US in papillary thyroid cancer likely detects non-actionable findings.

BACKGROUND: American Thyroid Association (ATA) low-intermediate-risk papillary thyroid cancer (PTC) patients without structural and biochemical evidence of disease on initial post-treatment evaluation have a low risk of recurrence. Studies have shown that with current ultrasound scans (US) and thyroglobulin assays, recurrences mostly occurred 2-8 years after initial therapy. The ATA recommends that neck US be done 6-12 months after surgery to establish patient's response to therapy, then periodically depending on risk of recurrence. The lack of clarity in recommendations on timing of follow-up US and fear of recurrence leads to frequent tests. OBJECTIVES: To evaluate the utility of routine neck US in ATA low-intermediate-risk PTC patients with no structural disease on neck US and non-stimulated thyroglobulin <1.0 ng/mL after initial therapy. METHODS: A retrospective study of 93 patients from Singapore, Saudi Arabia and Argentina with ATA low (n = 49) to intermediate (n = 44) risk PTC was conducted between 1998 and 2017. The outcome was to measure the frequency of identifying structural disease recurrence and non-actionable US abnormalities. RESULTS: Over a median follow-up of 5 years, five of the 93 patients (5.4%) developed structural neck recurrence on US at a median of 2.5 years after initial treatment. Indeterminate US abnormalities were detected in 19 of the 93 patients (20.4%) leading to additional tests, which did not detect significant disease. CONCLUSION: In ATA low-intermediate-risk PTC with no suspicious findings on neck US and a non-stimulated thyroglobulin of <1.0 ng/mL after initial therapy, frequent US is more likely to identify non-actionable abnormalities than clinically significant disease.

Facing a disruptive threat: how can a nuclear medicine service be prepared for the coronavirus outbreak 2020?

PURPOSE: The aim of this short communication is to outline our experience in policies and processes of a nuclear medicine service during the COVID-19 outbreak in Singapore. METHODS: We describe the key considerations of policies and processes that have been implemented in our nuclear medicine service since the first case of COVID-19 was confirmed in Singapore General Hospital on 23 January 2020, up to the present time. RESULTS: Infection control, screening of patients and visitors, segregation of risk groups, segregation of staff and service continuity plans, communication and staff welfare, using electronic platforms for multi-disciplinary meetings and tele-reporting are discussed. CONCLUSION: Since our hospital received the first patient with COVID-19 in Singapore, our centre has managed 16 COVID-19 cases to date. There has not been any healthcare worker in our institution who has contracted COVID-19 through patient contact. We have highlighted for discussion some of the policies and processes to prepare a nuclear medicine service for the COVID-19 threat.

Catheter-Directed Computed Tomography Hepatic Angiography for Yttrium-90 Selective Internal Radiotherapy of Hepatocellular Carcinoma Reduces Prophylactic Embolization of Extrahepatic Vessels.

OBJECTIVES: To determine the rate of prophylactic embolization of extrahepatic vessels in patients undergoing yttrium-90 selective internal radiotherapy (90Y SIRT) for hepatocellular carcinoma (HCC) with the use of catheter-directed computed tomography hepatic angiography (CD-CTHA). MATERIALS AND METHODS: This retrospective study included 186 HCC patients who received 90Y SIRT from May 2010 to June 2015 in a single institution. All procedures were performed in a hybrid angiography-CT suite equipped with digital subtraction angiography (DSA) and CD-CTHA capabilities. CD-CTHA was performed during pre-treatment hepatic angiography. 90Y SIRT was administered approximately 2 weeks later. Selective prophylactic embolization of extrahepatic vessels was performed if extrahepatic enhancement was seen on CD-CTHA or if an extrahepatic vessel opacified on DSA/CD-CTHA despite the final microcatheter position for 90Y microsphere delivery being beyond the origin of this vessel. RESULTS: Thirty-five patients (18.8%) required selective embolization of extrahepatic vessels. Technical success of 90Y SIRT was 99.5%. Two patients (1.1%) developed radiation-induced gastrointestinal ulceration, and one (0.54%) developed radiation-induced pneumonitis. Extrahepatic uptake of 90Y microspheres was seen in the gallbladder of one patient without significant complications. CONCLUSION: The use of CD-CTHA in 90Y SIRT of HCC was associated with a low rate of prophylactic embolization of extrahepatic vessels while maintaining a high technical success rate of treatment and low rate of complications. LEVEL OF EVIDENCE: Level 4, case series.

Current Status and Growth of Nuclear Theranostics in Singapore.

The concept of theranostics, where individual patient-level biological information is used to choose the optimal therapy for that individual, has become more popular in the modern era of 'personalised' medicine. With the growth of theranostics, nuclear medicine as a specialty is uniquely poised to grow along with the ever-increasing number of concepts combining imaging and therapy. This special report summarises the status and growth of Theranostic Nuclear Medicine in Singapore. We will cover our experience with the use of radioiodine, radioiodinated metaiodobenzylguanidine, peptide receptor radionuclide therapy, prostate specific membrane antigen radioligand therapy, radium-223 and yttrium-90 selective internal radiation therapy. We also include a section on our radiopharmacy laboratory, crucial to our implementation of theranostic principles. Radionuclide theranostics has seen tremendous growth and we hope to be able to grow alongside to continue to serve the patients in Singapore and in the region.

Clinicopathologic Characteristics and Survival of Patients with Gastroenteropancreatic Neuroendocrine Neoplasm in a Multi-Ethnic Asian Institution.

BACKGROUND: Epidemiological evidence suggests there are differences in gastroenteropancreatic neuroendocrine neoplasm (GEPNEN) among population groups. We aimed to contribute to the current evidence by evaluating the clinicopathological characteristics of GEPNEN in a multi-ethnic Asian group. MATERIALS AND METHODS: This was a retrospective chart review of patients diagnosed with GEPNEN at a tertiary medical institution at Singhealth Outram Campus, Singapore, between 1995 and 2015. RESULTS: Two hundred ninety-five patients were included in the evaluation, comprising Chinese (74.6%), Malay (4.4%), Indian (9.5%) and other (11.5%) ethnic backgrounds. The median age at diagnosis was 59 years; 52.5% were males. Distribution of disease stage at diagnosis was: localised (42.4%), regional (15.3%) and distant (38.0%). The three most common primary tumour sites were located in the pancreas (38.6%), rectum (19.7%) and stomach (9.5%), which varied significantly with ethnic background and age at diagnosis. Malay patients were younger (median 42 years) at diagnosis than Chinese (60 years). Patients with an appendiceal neuroendocrine neoplasm (NEN) (48 years) were younger compared to oesophageal NEN (66 years). Disease stage correlated with primary tumour site and grade (p < 0.001). Median overall survival (OS) for all GEPNEN was 10.2 years. Age at diagnosis, disease stage and grading were prognostic factors of OS in multivariable analyses. CONCLUSION: Our findings correspond with other studies that focus on GEPNEN incidences in Asian countries, with the pancreas, rectum and stomach being the most common primary tumour sites. Our findings suggest racial differences in primary tumour site and age at diagnosis. Further prospective population-based registries are required to understand these epidemiological differences.

Pancreatic metastasis detected by F-18 FDG PET/CT in a patient with breast cancer.

Pancreatic involvement by metastasis from other primaries is rare and accounts for approximately 2% to 4% of pancreatic tumors. In this article, we describe FDG-avid pancreatic involvement in a patient with diagnosis of breast cancer. We conclude that FDG PET can be a convenient noninvasive method of early detection of recurrence and in monitoring metastatic disease during follow-up in such patients. A positive FDG PET warrants histopathologic correlation for appropriate treatment.