Intracranial Metastasis from Prostate Cancer: Investigation, Incidence, and Imaging Findings in a Large Cohort of Australian Men

Brain metastasis: An insight into novel molecular targets for theranostic approaches

Brain metastases (BrM) are common malignant lesions in the central nervous system, and pose a significant threat in advanced-stage malignancies due to delayed diagnosis and limited therapeutic options. Their distinct genomic profiles underscore the need for molecular profiling to tailor effective treatments. Recent advances in cancer biology have uncovered molecular drivers underlying tumor initiation, progression, and metastasis. This, coupled with the advances in molecular imaging technology and radiotracer synthesis, has paved the way for the development of innovative radiopharmaceuticals with enhanced specificity and affinity for BrM specific targets. Despite the challenges posed by the blood-brain barrier to effective drug delivery, several radiolabeled compounds have shown promise in detecting and targeting BrM. This manuscript provides an overview of the recent advances in molecular biomarkers used in nuclear imaging and targeted radionuclide therapy in both clinical and preclinical settings. Additionally, it explores potential theranostic applications addressing the unique challenges posed by BrM.

Collet-Sicard syndrome caused by a paraganglioma in the region of the jugular foramen on one side: A case report and review

Collet-Sicard syndrome is a rare neurological disorder caused by injury to the cranial nerve pairs IX, X, X, and XII. The author reports on a previously fit 27-year-old man who presented with dysphagia, choking on drinking water, hoarseness, weakness when turning the neck and shrugging the shoulders, and unexplained weight loss. Enhanced magnetic resonance imaging indicated a space-occupying lesion at the right jugular foramen. After surgical resection, the pathologic findings suggested a paraganglioma of the right jugular foramen and confirmed the diagnosis of Collet-Sicard syndrome. After postoperative treatment with a combination of acupuncture and modern medicine, the patient's symptoms significantly improved. This article analyzes previous literature regarding Collet-Sicard syndrome etiology and reports the case of a patient with a rare etiology, whose prognosis improved significantly after treatment with a combination of acupuncture and modern medicine.

Late Subacute Cerebral Hematoma Mimicking a Metastasis on PSMA PET/CT

ABSTRACT

A 64-year-old man with history of prostate cancer was found to have rising prostate-specific antigen after radical prostatectomy. 18 F-DCFPyL PET/CT demonstrated a prostate-specific membrane antigen-avid brain lesion in the left frontal lobe and no other findings to account for rising prostate-specific antigen. Brain MRI demonstrated a small intraparenchymal hematoma with late subacute features in this location. The patient reported a seizure 3 weeks before but was otherwise asymptomatic, and neurologic examination was normal. Follow-up MRI demonstrated gradual decrease in size of the hematoma without treatment.

Coadministration of ABCB1/P-glycoprotein inhibitor elacridar improves tissue distribution of ritonavir-boosted oral cabazitaxel in mice

Developing an oral formulation for the chemotherapeutic cabazitaxel might improve its patient-friendliness, costs, and potentially exposure profile. Cabazitaxel oral availability is restricted by CYP3A-mediated first-pass metabolism, but can be substantially boosted with the CYP3A inhibitor ritonavir. We here tested whether adding the ABCB1/P-glycoprotein inhibitor elacridar to ritonavir-boosted oral cabazitaxel could further improve its tissue exposure using wild-type, CYP3A4-humanized and Abcb1a/b-/- mice. The plasma AUC0-2h of cabazitaxel was increased 2.3- and 1.9-fold in the ritonavir- and ritonavir-plus-elacridar groups of wild-type, and 10.5- and 8.8-fold in CYP3A4-humanized mice. Elacridar coadministration did not influence cabazitaxel plasma exposure. The brain-to-plasma ratio of cabazitaxel was not increased in the ritonavir group, 7.3-fold in the elacridar group and 13.4-fold in the combined booster group in wild-type mice. This was 0.4-, 4.6- and 3.6-fold in CYP3A4-humanized mice, illustrating that Abcb1 limited cabazitaxel brain exposure also during ritonavir boosting. Ritonavir itself was also a potent substrate for the Abcb1 efflux transporter, limiting its oral availability (3.3-fold) and brain penetration (10.6-fold). Both processes were fully reversed by elacridar. The tissue disposition of ritonavir-boosted oral cabazitaxel could thus be markedly enhanced by elacridar coadministration without affecting the plasma exposure. This approach should be verified in selected patient populations.

Unusual Presentation of Prostate Cancer: A Case Report

Prostate cancer is the second-most common malignancy in males. Despite more frequently metastasizing to the bone, regional lymph nodes, and liver, the brain can also be affected. These metastases can simulate meningiomas, making the diagnosis more difficult. Here, we report the case of a 62-year-old male with a sudden onset of confusion and dysarthria with spontaneous resolution but amnesia for the event. On a neurological exam, the patient had left exophthalmos and palpebral ptosis. He was referred to the emergency room, where he underwent a cranioencephalic CT, which revealed a left anterior temporal lesion with adjacent edema suggestive of meningioma, later confirmed by an MRI. Due to the worsening of the symptoms and an increase in the size of the lesion, total resection was proposed. The anatomopathological study revealed a poorly differentiated carcinoma. To study the primary tumor, a CT of the thorax, abdomen, and pelvis; a spine MRI; and a complementary study with prostate-specific antigen were requested. These studies revealed a prostate adenocarcinoma with brain and bone metastases. After the diagnosis, the patient underwent hormone therapy, chemotherapy, and palliative radiotherapy.

Use of 18 F-PSMA PET to Distinguish Cerebral Radiation Necrosis From Tumor Recurrence

ABSTRACT

Brain metastasis in prostate adenocarcinoma is extremely rare and usually arises in the setting of widespread osseous and visceral metastases. Surgical resection and radiation therapy, including stereotactic radiosurgery, are the mainstays of treatment for brain metastasis. Radiation necrosis is a common complication of radiotherapy for brain metastasis, and distinguishing it from tumor recurrence by MRI is difficult because of overlapping findings. We present a 73-year-old man with prostate cancer with a solitary brain metastasis where PET with 18 F-piflufolostat helped detect disease recurrence in the setting of ambiguous MRI findings.

Prostate-Specific Membrane Antigen as Target for Neuroimaging of Central Nervous System Tumors

Introduction. Positron emission tomography (PET) imaging with prostate-specific membrane antigen- (PSMA-) binding tracers has been found incidentally to demonstrate uptake in CNS tumors. Following the encouraging findings of several such case reports, there is a growing interest in the potential application of PSMA-targeted PET imaging for diagnostics, theranostics, and monitoring of CNS tumors. This is a systematic literature review on PSMA-binding tracers in CNS tumors. Methods. A PubMed search was conducted, including preclinical and clinical reports. One hundred and twelve records were identified, and after screening, 56 were included in the final report. Results. Tissue studies demonstrated PSMA expression in tumor vascular endothelial cells, without expression in normal brain tissue, though the extent and intensity of staining varied by anti-PSMA antibody and methodology. Most included studies reported on gliomas, which showed strong PSMA ligand uptake and more favorable tumor to background ratios than other PET tracers. There are also case reports demonstrating PSMA ligand uptake in prostate cancer brain metastases, nonprostate cancer brain metastases, and meningiomas. We also review the properties of the various PSMA-binding radiotracers available. Therapeutic and theranostic applications of PSMA-binding tracers have been studied, including labeled alpha- and beta-ray emitting isotopes, as well as PSMA targeting in directing MRI-guided focused ultrasound. Conclusions. There is a potential application for PSMA-targeted PET in neuro-oncology as a combination of diagnostic and therapeutic use, as a theranostic modality for managing CNS tumors. Further research is needed regarding the mechanism(s) of PSMA expression in CNS tumors and its differential performance by tumor type.