Castration-Resistant Prostate Cancer: From Uncovered Resistance Mechanisms to Current Treatments.

Prostate cancer (PC) is the second most common cancer in men worldwide. Despite recent advances in diagnosis and treatment, castration-resistant prostate cancer (CRPC) remains a significant medical challenge. Prostate cancer cells can develop mechanisms to resist androgen deprivation therapy, such as AR overexpression, AR mutations, alterations in AR coregulators, increased steroidogenic signaling pathways, outlaw pathways, and bypass pathways. Various treatment options for CRPC exist, including androgen deprivation therapy, chemotherapy, immunotherapy, localized or systemic therapeutic radiation, and PARP inhibitors. However, more research is needed to combat CRPC effectively. Further investigation into the underlying mechanisms of the disease and the development of new therapeutic strategies will be crucial in improving patient outcomes. The present work summarizes the current knowledge regarding the underlying mechanisms that promote CRPC, including both AR-dependent and independent pathways. Additionally, we provide an overview of the currently approved therapeutic options for CRPC, with special emphasis on chemotherapy, radiation therapy, immunotherapy, PARP inhibitors, and potential combination strategies.

Nuclear medicine in pheochromocytoma and paraganglioma: at a crossroads with precision medicine.

Precision medicine (PM) aims to maximize the risk-benefit balance of medical decisions by integrating individual patient and disease characteristics. This approach is gaining increasing recognition from clinicians, healthcare systems, pharmaceutical companies, patients, and governments. Nuclear medicine plays a critical role in PM by its virtue of providing critical information at every step of disease management, digital markers, and companion diagnostics/therapeutics. It is anticipated that technological breakthroughs and new tracers will continue to position nuclear medicine among the significant players in PM.

Lymph node thyroglobulin in the diagnosis of metastases of thyroid carcinoma with the thyroid in situ: A prospective intraoperative study.

BACKGROUND: The use of thyroglobulin concentration in washout fluid of fine-needle aspiration (FNA-Tg) is a procedure advocated by international guidelines to diagnose metastatic LN in papillary thyroid cancer. With the increasing use of active follow-up or lobectomy alone for low-risk thyroid cancers, the determination of the diagnostic performance of FNA-Tg in the detection of metastatic PTC when the thyroid is in situ is paramount. MATERIALS AND METHODS: Prospective study with measurement of Tg in washout fluid obtained from intraoperative fine needle aspiration (FNA) cytology in order to avoid contamination from thyroid tissue and rigorously isolated punctured nodes. Receiver-operating characteristic (ROC) curve and area under the curve (AUC), optimal threshold to discriminate benign and malignant LN, sensitivity and specificity were provided. RESULTS: a total of 58 lymph nodes from 32 patients were analyzed. ROC analysis defined the optimal cutoff values of FNA-Tg at 60 ng/ml for the diagnosis of malignant LNs in patients with a thyroid in situ. Sensitivity and specificity were 75% (95% confidence interval 57.89-86.75) and 87.5% (95%CI: 69-95.66), respectively. CONCLUSION: Our results support the hypothesis that the Tg-FNA threshold for a safe diagnosis of LN metastasis in PTC is higher in presence of a thyroid gland in situ. The use of lower thresholds could result in false positive results and lead to unnecessary surgery.

Diagnostic Rechallenge with 18F-FCH PET/CT Often Allows Minimally Invasive Parathyroidectomy While Maintaining Exceptional Cure Rates.

BACKGROUND: Minimally invasive parathyroidectomy (MIP) has gained acceptance as the preferred surgical procedure for management of primary hyperparathyroidism (pHPT). Appropriate selection of patients for a MIP is a crucial step in its utilization. The aim of the study was to evaluate the role of 18F-FCH PET/CT as second-line imaging for accurately directing MIP. METHODS: This is a retrospective single-center study. Seventy-two patients with biochemical evidence of pHPT and a non-conclusive or negative first-line imaging (ultrasound and dual isotope subtraction scintigraphy) received 18F-FCH PET/CT between January 2018 and February 2020. All imaging studies were performed at our institution. Assessment of therapeutic changes and outcomes was performed. RESULTS: of the 72 patients imaged with 18F-FCH PET/CT, 54 subsequently underwent parathyroidectomy. When considering the ability of 18F-FCH PET/CT alone to predict a uniglandular disease, the sensitivity, specificity, PPV and NPV were 92.7% (95%CI: 80.1-98.5), 46.2% (19.2-74.9), PPV 87.3% (80.5-92) and NPV 61.2% (31.4-84.5), respectively. When we combined the data provided by 18F-FCH PET/CT with the data already collected from 1st line imaging we were able to complete a minimally invasive surgery in 38 of the 41 (92%) patients with a uniglandular disease. Thirteen patients (24%) had a multiglandular disease, all of them except one underwent bilateral neck exploration based on the data collected by all imaging modalities combined. Overall, cure was achieved in 53 (98%) patients. CONCLUSION: 18F-FCH PET/CT, interpreted along with first-line imaging results in selected patients, can better facilitate utilization of MIS while maintaining exceptional cure rates.

Molecular imaging of endocrine neoplasms with emphasis on 18F-DOPA PET: a practical approach for well-tailored imaging protocols.

6-[18F]-L-fluoro-L-3, 4-dihydroxyphenylalanine (18F-DOPA) PET/CT can be a useful tool for the detection of different neuroendocrine tumors (NETs). The main determinants of 18F-DOPA uptake and retention by NETs are related to expression of LAT1/LAT2 transporters, expression and activity of AADC and biochemical phenotype, all being intimately inter-connected to their embryological origin. In order to improve sensitivity of 18F-DOPA PET, it is of main importance to perform indivisualized imaging protocols across primaries. This review provides a practical approach for performing well-tailored imaging protocols and describes the clinical value of the recommended radiopharmaceuticals.

Clinical utility of nuclear imaging in the evaluation of pediatric adrenal neoplasms.

Adrenal neoplasms rarely occur in children. They can be diagnosed in the presence of endocrine, metabolic or neurological problems, an abdominal mass, more rarely an adrenal incidentaloma, or in the context of an adrenal mass discovered in the evaluation of childhood cancer including hematologic malignancy. According to standard medical practice, pediatric malignancies are almost always evaluated by 18F-fluorodeoxyglucose positron emission tomography with computed tomography ([18F]FDG PET/CT). Nuclear imaging using specific radiotracers is also an important tool for diagnosing and staging neuroblastoma, pheochromocytoma, hormone hypersecretion, or indeterminate adrenal masses. The Hippocratic oath "primum non nocere" encourages limitation of radiation in children per the ALARA concept (as low as reasonably achievable) but should not lead to the under-use of nuclear imaging because of the potential risk of inaccurate diagnosis or underestimation of the extent of disease. As in adults, nuclear imaging in children should be performed in conjunction with hormone evaluation and morphological imaging.