Translate this page into:
Demonstration of 68Ga-prostate-specific Membrane Antigen Uptake in Metastatic Pancreatic Neuroendocrine Tumor
Address for correspondence: Dr. Nishikant Avinash Damle, Department of Nuclear Medicine, AIIMS, Ansari Nagar, New Delhi - 110 029, India. E-mail: nkantdamle@gmail.com
This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.
This article was originally published by Medknow Publications & Media Pvt Ltd and was migrated to Scientific Scholar after the change of Publisher.
Abstract
We present the case of a 47-year-old female with metastatic pancreatic neuroendocrine tumor (NET). The patient was treated with long-acting octreotide which failed to halt disease progression. The patient was being considered for 177Lu-peptide receptor radionuclide therapy, and a 68Ga-DOTANOC positron emission tomography-computed tomography (PET-CT) was acquired initially, which showed good uptake in the primary and metastatic lesions. Metastatic pancreatic NETs have limited treatment options, and given the background that these tumors are highly vascular and prostate-specific membrane antigen (PSMA) expression is known in the endothelium of tumor neovasculature, we decided to perform a 68Ga-PSMA-HBED-CC PET-CT scan. It revealed radiotracer uptake in the metastatic liver lesions although not as high as 68Ga-DOTANOC-PET-CT. PSMA expression needs to be researched further, especially in high-grade NETs where somatostatin expression may be poor.
Keywords
68Ga-prostate-specific membrane antigen positron emission tomography-computed tomography
neuroendocrine tumor
theranostics
Prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET-CT) has been extensively used in the management of patients with prostate cancer. This tracer also offers an important example of the concept of theranostics. However, PSMA expression has also been reported previously in other malignancies such as bladder, breast, gastric, colon, rectum, lung, renal cell carcinoma, hepatocellular carcinoma, multiple myeloma, and follicular lymphoma and in few nonneoplastic conditions.[123456789] Very few studies have shown expression of PSMA in neuroendocrine tumors (NETs).[10] It is well known from some earlier studies that PSMA expression is seen in the endothelium of tumor neovasculature. Since NETs have very high vascularity, PSMA expression may be seen in the same. In this case, PSMA-PET-CT showed uptake in the primary tumor in the pancreas and metastatic liver lesions. The uptake was high in the periphery of the tumor concordant with the expected distribution of neovasculature. However, the intensity of the uptake was low as compared to 68Ga-DOTANOC. The number of lesions seen on PSMA-PET/CT was much less than that seen on DOTANOC-PET/CT [Figure 1]. However, it remains to be seen how much uptake will be seen in high-grade NETs which are known to be poorly DOTANOC avid. This finding may encourage researchers to consider this modality from the theranostic point of view in a disease with limited treatment options.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
- Five different anti-prostate-specific membrane antigen (PSMA) antibodies confirm PSMA expression in tumor-associated neovasculature. Cancer Res. 1999;59:3192-8.
- [Google Scholar]
- Expression of prostate-specific membrane antigen in normal and malignant human tissues. World J Surg. 2006;30:628-36.
- [Google Scholar]
- Incidental prostate-specific membrane antigen uptake in a peripheral nerve sheath tumor. Clin Nucl Med. 2017;42:560-2.
- [Google Scholar]
- Serous cystadenoma of the pancreas showing uptake on 68Ga PSMA PET/CT. Clin Nucl Med. 2017;42:56-7.
- [Google Scholar]
- Elevated 68Ga prostate-specific membrane antigen activity in metastatic non-small cell lung cancer. Clin Nucl Med. 2016;41:414-6.
- [Google Scholar]
- Follicular lymphoma showing avid uptake on 68Ga PSMA-HBED-CC PET/CT. Clin Nucl Med. 2016;41:500-1.
- [Google Scholar]
- Prostate-specific membrane antigen (PSMA) avid pancreatic neuroendocrine tumor. Clin Nucl Med. 2016;41:804-6.
- [Google Scholar]