18F-PSMA 1007 Uptake in a Man With Metastatic Breast Cancer

Incidental Diagnosis of Metastatic Breast Cancer in a Man With 99m Tc-PSMA SPECT/CT

ABSTRACT

Breast cancer in men is a rare and unsuspected malignancy. A 48-year-old man begins with disabling low back pain. The CT scan reported a compression fracture in L2 and diffuse skeletal lesions suggestive of metastatic disease. The serum prostate-specific antigen was 6.2 ng/mL. He was referred for SPECT/CT with 99m Tc-EDDA/HYNIC-inhibitor prostate-specific membrane antigen due to clinical suspicion of prostate cancer. SPECT/CT with 99m Tc-EDDA/HYNIC-inhibitor prostate-specific membrane antigen showed a primary lesion in the left breast and multiple bone lesions. Biopsy confirmed infiltrating ductal carcinoma with positive hormone receptors and indeterminate HER2 (human epidermal growth factor receptor 2).

F-18 PSMA Uptake in Male Breast Cancer during Restaging Evaluation of Carcinoma Prostate

Fluorine-18 prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography scan is widely used for restaging of prostate cancer. We present a case where false-positive PSMA uptake was seen in metachronous carcinoma breast during restaging workup of carcinoma prostate.

Prostate-Specific Membrane Antigen Expression in Metastatic Angiosarcoma Detected on 18F-PMSA PET/CT: A New Potential Prognostic Marker

ABSTRACT

18F-PSMA is a promising tracer for both staging and detection of biochemical recurrence in prostate cancer. PSMA is also expressed in the endothelium of tumor-associated neovasculature of various solid malignancies possibly due to tumor-associated angiogenic factors and endothelial cell sprouting. We report a case of a 59-year-old man with known case of prostate cancer underwent 18F-PSMA for restaging. 18F-PSMA PET/CT shows multiple lytic bone lesions with high PSMA expression. Histopathological evaluation showed metastatic angiosarcoma. 18F-PSMA expression in the angiosarcoma can be potentially guided to radionuclide legend therapy.

Head-to-head comparison between 68Ga-PSMA and 18F-FDG-PET/CT in lymphomas: a preliminary analysis

PURPOSE

Isolated case reports mention the uptake of radiolabeled PSMA in lymphoma. However, it is not clear if the intensity of 68Ga-PSMA expression varies among different histological subtypes or if it correlates with 18F-FDG uptake. This study compared both tracers in patients with diverse lymphoma subtypes.

METHODS

Ten patients with biopsy-proven-lymphoma underwent 18F-FDG and 68Ga-PSMA-PET/CT (maximum time interval: 6 days). Lymphoma subtypes included Hodgkin's lymphoma (HL, three patients) and aggressive and indolent non-Hodgkin's lymphoma (NHL, seven patients). The intensity of PSMA uptake was classified visually as low, intermediate, or high, using blood pool, liver and parotid gland uptake as references. Maximum standardized-uptake value (SUVmax) of each affected site was measured in both sets of images.

RESULTS

FDG detected 59/59 involved sites in 10 patients and PSMA 47/59 sites in nine patients. PSMA uptake was generally low, regardless of the intensity of FDG uptake, but it was classified as intermediate in two patients. The median SUVmax varied from 2.0 (2.0-8.2) to 30.9 for FDG and from 1.7 (1.7-1.7) to 4.4 for PSMA, P < 0.0001. The primary lesion of one patient had a marked intralesional mismatch uptake pattern of the tracers, with areas of higher PSMA expression than FDG uptake, and vice-versa. A brain lesion was more easily identified with PSMA than with FDG images.

CONCLUSION

HL and several NHL subtypes may present PSMA uptake. The intensity of PSMA expression is generally lower than that of FDG uptake and seems to present less variation among the different histological subtypes of lymphomas.

The utility of radiolabeled PSMA ligands for tumor imaging

Prostate-specific membrane antigen (PSMA) is a glycosylated type-II transmembrane protein expressed in prostatic tissue and significantly overexpressed in several prostate cancer cells. Despite its name, PSMA has also been reported to be overexpressed in endothelial cells of benign and malignant non-prostate disease. So its clinical use was extended to detection, staging, and therapy of various tumor types. Recently small molecules targeting PSMA have been developed as imaging probes for diagnosis of several malignancies. Preliminary studies are emerging improved diagnostic sensitivity and specificity of PSMA imaging, leading to a change in patient management. In this review, we evaluated the first preclinical and clinical studies on PSMA ligands resulting future perspectives radiolabeled PSMA in staging and molecular characterization, based on histopathologic examinations of PSMA expression.

PSMA radioligand therapy for solid tumors other than prostate cancer: background, opportunities, challenges, and first clinical reports

In the past decade, a growing body of literature has reported promising results for prostate-specific membrane antigen (PSMA)-targeted radionuclide imaging and therapy in prostate cancer. First clinical studies evaluating the efficacy of [¹⁷⁷Lu]Lu-PSMA radioligand therapy (PSMA-RLT) demonstrated favorable results in prostate cancer patients. [¹⁷⁷Lu]Lu-PSMA is generally well tolerated due to its limited side effects. While PSMA is highly overexpressed in prostate cancer cells, varying degrees of PSMA expression have been reported in other malignancies as well, particularly in the tumor-associated neovasculature. Hence, it is anticipated that PSMA-RLT could be explored for other solid cancers. Here, we describe the current knowledge of PSMA expression in other solid cancers and define a perspective towards broader clinical implementation of PSMA-RLT. This review focuses specifically on salivary gland cancer, glioblastoma, thyroid cancer, renal cell carcinoma, hepatocellular carcinoma, lung cancer, and breast cancer. An overview of the (pre)clinical data on PSMA immunohistochemistry and PSMA PET/CT imaging is provided and summarized. Furthermore, the first clinical reports of non-prostate cancer patients treated with PSMA-RLT are described.

Fluorine-18 labelled prostate-specific membrane antigen (PSMA)-1007 positron-emission tomography-computed tomography: normal patterns, pearls, and pitfalls

Prostate-specific membrane antigen (PSMA)-based positron-emission tomography (PET)-computed tomography (CT) has shown great promise in prostate cancer imaging. This technique has demonstrated particular utility in the staging of high-risk primary cancer and in the localisation of recurrent disease. The use of fluorine-18 PSMA-1007 is advantageous, as it is excreted via the hepatobiliary system rather than urinary and the longer half-life of fluorine-18 compared to gallium tracers, allows for PSMA imaging in centres without a gallium generator. However, imaging with this tracer is not without flaws and areas of ambiguity remain. In this article, the biodistribution, clinical indications, and pearls of ¹⁸F-PSMA-1007 PET-CT in patients with prostate cancer will be discussed, as well as the potential pitfalls in the reporting of these studies.