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

Abstract

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.

18F-Prostate-Specific Membrane Antigen and 18F-Fluorodeoxyglucose PET/CT Unmasked the Characteristics of Prostate Lymphoma: A Case Report and Literature Review

“…In the past, a needle biopsy was the standard method to identify whether extra-prostate tissue involvement was present, while it may lead to some complications (i.e., bleeding and infection). Recently, de Souza et al pointed out that lymphoma may present as PSMA uptake after reviewing the data of 10 patients with different histological subtypes of lymphomas, and they subsequently found that the intensity of PSMA uptake was generally lower than FDG ( 11 ). Furthermore, several published case reports have also found that the PSMA expression of lymphoma was extremely low, or even had no expression ( 12 – 14 ).…”

Prostate-Specific Membrane Antigen PET Positivity in a Lung Mass

“…Only one other report identified in the literature showed a patient with a history of diffuse large B-cell lymphoma to be positive on PSMA PET scan. 8 Given the increasing availability of the PSMA PET scan after Food and Drug Administration approval in December 2020 because of its superiority to conventional imaging in detecting prostate cancer metastases, 9,10 it is important to be aware of the landscape of other diseases, such as lymphoma, which this seemingly specific scan can detect. This case emphasizes the importance of confirmatory biopsy when atypical findings occur on a 68 Ga-PSMA PET scan.…”

“…To the best of our knowledge, this is the first case of a previously unknown high-grade lymphoma diagnosed via PSMA PET/CT. Only one other report identified in the literature showed a patient with a history of diffuse large B-cell lymphoma to be positive on PSMA PET scan 8 . Given the increasing availability of the PSMA PET scan after Food and Drug Administration approval in December 2020 because of its superiority to conventional imaging in detecting prostate cancer metastases, 9,10 it is important to be aware of the landscape of other diseases, such as lymphoma, which this seemingly specific scan can detect.…”

PSMA Immunohistochemistry in Hepatic Neoplasms

“…14,15 Furthermore, lutetium-177-labeled PSMA shows promising results for successful endoradiotherapeutic treatment of metastatic hormone-sensitive and castration-resistant prostate cancer with survival benefits. 12,13 Interestingly, PSMA PET avidity has also been reported to occur in nonprostatic malignancies to include glioblastoma, 16 hematolymphoid malignancies, 17,18 thyroid cancer, 19 and HCC. [20][21][22][23][24] For liver cancer, PSMA-targeted radioligands may have significant clinical implications as diagnostic imaging and management of HCC in cirrhotic patients remain challenging.…”