Purpose of the Report Prostate-specific membrane antigen (PSMA) is a type II membrane glycoprotein, which is not only overexpressed in prostate cancers but also in variety of solid tumors including glioblastoma multiforme. The aim of the present study was to demonstrate PSMA expression in gliomas using 68Ga-PSMA-HBED-CC(PSMA 11) PET/CT. Patients and Methods Ten patients with initially MRI suspected and eventually histopathologically proven gliomas [8 males (age range 30–73 yr; mean age 51.8 yr); 2 females aged 39 and 55 years] were subjected preoperatively to regional brain PET scan with 68Ga-PSMA-11 and 18F-FDG PET/CT. Final histopathology of brain lesions, their MIB-1 proliferation index (MIB-1 PI) were compared with PSMA and FDG PET findings. Results FDG PET/CT showed distinct FDG uptake in high-grade gliomas, whereas low-grade gliomas were non-FDG-avid amidst physiological tracer uptake. In vivo PSMA expression was seen in all patients with glioma. Of these, the 7 patients of glioblastoma harboring 8 lesions showed significantly higher PSMA expression than those with low-grade gliomas, average SUVmax being 16.93 and 2.93, respectively. Similarly, average tumor-to-background ratios (13.95 and 3.42, respectively) and MIB-1 PI (17.31 and 3.3, respectively) were substantially more in high-grade versus low-grade gliomas. Conclusions The results of this pilot study show that 68Ga-HBED-CC-PSMA PET/CT can be used to characterize the PSMA expression in gliomas, high-grade ones demonstrating higher SUVmax, MIB-1 PI tumor-to-background ratio than the low-grade ones. With these results as basis, certain patients may benefit from potential PSMA-targeted radionuclide therapy.

Introduction: 177Lu-DOTATATE-based peptide receptor radionuclide therapy (PRRT) is a promising therapy for metastatic and/ inoperable pheochromocytoma and paraganglioma (PPGL). We aim to evaluate the efficacy and safety of and identify predictors of response to 177Lu-DOTATATE therapy in metastatic and/ inoperable PPGL. Methods: This retrospective study involved 15 patients of metastatic or unresectable PPGL, who received 177Lu-DOTATATE PRRT therapy. Clinical, biochemical (Plasma free normetanephrine), and radiological (anatomical and functional) responses were compared before and after the last therapy. Results: A total of 15 patients PCC (4), sPGL (4), HNPGL (5), PCC+sPGL (1), HNPGL+sPGL (1) were included. The median duration of follow up was 27 (range: 11-62) months from the start of PRRT. Based on the RECIST (1.1) criteria, progressive disease was seen in three (20%), stable disease in eight (53 %), partial response in one (7%), and minor response in three (20%) and controlled disease in 12 (80%). On linear regression analysis presence of PGL (p= 0.044) and baseline SUVmax >21 (p < 0.0001) were significant positive predictors of early response to PRRT. Encouraging safety profiles were noted with no long term nephrotoxicity and haematotoxicity. Conclusion: 177Lu-DOTATATE therapy is an effective and safe modality of treatment for patients with metastatic/inoperable PPGL. Although it is not prudent to withhold PRRT in metastatic PPGL with baseline SUVmax < 21, baseline SUVmax >21 can be used to predict early response to PRRT.

Ga-PSMA-HBED-CC PET/CT is a potentially useful imaging modality in patients of mDTC with most (70%) of PSMA expressing metastasis being localized to the bones. PSMA PET/CT could be useful for identifying patients with limited therapeutic options (eg, TENIS) who might benefit from PSMA-targeted radionuclide therapy.

Majority of patients obtained CR/VGPR post-ASCT. Longer PFS was seen with patients who were transplanted in first remission.