Search

The ability to accurately differentiate treatment-related changes (ie, pseudoprogression and radiation necrosis) from recurrent glioma remains a critical diagnostic problem in neuro-oncology. Because these entities are treated differently and have vastly different outcomes, accurate diagnosis is necessary to provide optimal patient care. In current practice, this diagnostic quandary commonly requires either serial imaging or histopathologic tissue confirmation. In this article, experts in the field debate the utility of 2-deoxy-2[18F]fluoro-d-glucose positron emission tomography (FDG PET) as an imaging tool to distinguish tumor recurrence from treatment-related changes in a patient with glioblastoma and progressive contrast enhancement on magnetic resonance (MR) following chemoradiotherapy.

Nuclear receptors are transcription factors that function in normal physiology and play important roles in diseases such as cancer, inflammation, and diabetes. Noninvasive imaging of nuclear receptors can be achieved using radiolabeled ligands and positron emission tomography (PET). This quantitative imaging approach can be viewed as an in vivo equivalent of the classic radioligand binding assay. A main clinical application of nuclear receptor imaging in oncology is to identify metastatic sites expressing nuclear receptors that are targets for approved drug therapies and are capable of binding ligands to improve treatment decision-making. Research applications of nuclear receptor imaging include novel synthetic ligand and drug development by quantifying target drug engagement with the receptor for optimal therapeutic drug dosing and for fundamental research into nuclear receptor function in cells and animal models. This mini-review provides an overview of PET imaging of nuclear receptors with a focus on radioligands for estrogen receptor, progesterone receptor, and androgen receptor and their use in breast and prostate cancer. [ABSTRACT FROM AUTHOR]

Simple Summary: Prostate cancer is the most common cancer in men and, along with the aggressive neuroendocrine variant of prostate cancer, is known to express high levels of the somatostatin receptor. This study explored the feasibility of using the somatostatin binding radiopharmaceutical, [68Ga]Ga-DOTATATE PET/CT, to identify metastatic lesions in 17 men with known metastatic castrate resistant prostate cancer or neuroendocrine prostate cancer. All patients demonstrated [68Ga]Ga-DOTATATE avid lesions corresponding to sites of disease as identified by CT. Additionally, we retrospectively correlated the degree of [68Ga]Ga-DOTATATE to treatment response and found that men with marked [68Ga]Ga-DOTATATE uptake in their metastatic deposits had significantly worse outcomes compared to those with moderate or mild [68Ga]Ga-DOTATATE uptake. Conversely, men with only mild [68Ga]Ga-DOTATATE uptake in their metastatic deposits had a favorable prognostic outcome. Objectives: Prostate cancer is well known to express high levels of somatostatin receptors and preliminary data suggests that PET imaging with the somatostatin analog, [68Ga]Ga-DOTATATE, may allow for whole body staging of patients with metastatic castration resistant prostate cancer (mCRPC) and neuroendocrine prostate cancer (NePC). This study explores the utility of [68Ga]Ga-DOTATATE PET-CT to identify metastatic deposits in men with mCRPC and NePC and prognosticate disease progression. Methods: [68Ga]Ga-DOTATATE PET-CT was performed in 17 patients with mCRPC and of those, 2/17 had NePC. A semiquantitative analysis with standardized uptake values (SUV) (e.g., SUVmax, SUVmean) was performed for each metastatic lesion and reference background tissues. [68Ga]Ga-DOTATATE uptake in metastatic deposits was further classified as: mild (less than liver), moderate (up to liver average), or marked (greater than liver). Serial prostate-specific antigen measurements and patient survival were followed up to 3 years after PET imaging to assess response to standard of care treatment. Results: All patients had at least one metastatic lesion with identifiable [68Ga]Ga-DOTATATE uptake. Marked [68Ga]Ga-DOTATATE uptake was found in 7/17 patients, including both NePC patients, and all were non-responders to systemic therapy and died within the follow up period, with a mean time to death of 8.1 months. Three patients had mild [68Ga]Ga-DOTATATE uptake, and all were responders to systemic therapy and were alive 36 months after [68Ga]Ga-DOTATATE imaging. Conclusions: [68Ga]Ga-DOTATATE is able to identify mCRPC and NePC metastatic deposits, and lesions with [68Ga]Ga-DOTATATE uptake > liver may portend poor outcomes in patients with mCRPC. [ABSTRACT FROM AUTHOR]

Radiopharmaceutical therapy using 177Lu-prostate-specific membrane antigen (PSMA) is an effective prostate cancer treatment that was recently approved by the U.S. Food and Drug Administration. This method leverages the success of PSMA-targeted PET imaging, enabling delivery of targeted radiopharmaceutical therapy; has demonstrated a clear benefit in large prospective clinical trials; and promises to become part of the standard armamentarium of treatment for patients with prostate cancer. This review highlights the evidence supporting the use of this agent, along with important areas under investigation. Practical information on technology aspects, dose administration, nursing, and the role of the treating physician is highlighted. Overall, 177Lu-PSMA treatment requires close collaboration among referring physicians, nuclear medicine technologists, radiopharmacists, and nurses to streamline patient care. [ABSTRACT FROM AUTHOR]

aim E Parent,4 Han Tun11Division of Hematology and Medical Oncology, Mayo Clinic Hospital, Jacksonville, FL, 32224, USA; 2Department of Internal Medicine, Mayo Clinic Hospital, Jacksonville, FL, 32224, USA; 3Department of Pathology, Mayo Clinic Hospital, Jacksonville, FL, 32224, USA; 4Nuclear Medicine Division of Radiology Department, Mayo Clinic, Jacksonville, FL, 32224, USACorrespondence: Adam M Kase, Division of Hematology and Medical Oncology, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA, Tel +1 904-953-2000, Fax +1 904-953-2315, Email [email protected] Cerebral glucose hypometabolism (CGHM) is characterized by diffuse or focal reduction in uptake of glucose by the brain as determined on a FDG PET-CT. We report a case of lymphoma-associated cerebral glucose hypometabolism (LA-CGHM) in a patient with hepatosplenic T-cell lymphoma (HSTCL) whose neuropsychiatric symptoms were resolved with glucose supplementation. PET-CT scan showed diffuse cerebral hypometabolism in addition to focal hypermetabolism in the liver related to lymphomatous involvement. He responded rapidly to infusion of 10% dextrose with complete resolution of neurological symptoms on two separate occasions and was later maintained on oral glucose without relapse. While his neuropsychiatric symptoms improved, his aggressive lymphoma and chemo-refractory disease ultimately led to his demise. We suggest that LA-CGHM can cause neuropsychiatric manifestations which can be reversed by intensive glucose supplementation. [ABSTRACT FROM AUTHOR]