1. COMPARISON OF PET/CT IMAGES WITH 18F-FDG AND 18F-PSMA-1007 IN MUSCULOSKELETAL TUMORS TO EVALUATE THE POTENTIAL OF THERANOSTICS APPROACH
- Author
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Mayara Branco E. Silva, Natalia Tobar, Allan de Oliveira Santos, Gardenia De Oliveira Barbosa, Carlos Eduardo Hideo Hanasilo, Mariana Da Cunha Lopes de Lima, Mauricio Etchebehere, and Elba Cristina Sa de Camargo Etchebehere
- Subjects
Musculoskeletal tumors ,PET FDG ,PET PSMA ,Theranostic ,Diseases of the blood and blood-forming organs ,RC633-647.5 - Abstract
Introduction/Justification: Sarcomas are malignant tumors in the bone, cartilage, fat, muscles, and vessels. Sar- comas are highly heterogeneous due to the wide variety of histological subtypes and various ana- tomical locations, and thus, the diagnosis and management of these tumors are challenging. Beyond sarcomas, the musculoskeletal system is a frequent site of metastatic tumors and multiple myeloma with lesions that present difficult local control. Imaging exams such as MRI and 18F-FDG (FDG PET/CT) to assess the extent of these tumors play a crucial role in managing these patients. How- ever, PET/CT imaging with 18F-PSMA-1007 (PSMA PET/CT) may be a more interesting diagnostic marker due to the potential Theranostics implications. Objectives: This study aimed to compare the performance of FDG PET/CT and PSMA PET/CT images in patients with advanced-stage unresectable recurrent and metastatic musculoskeletal tumors. Materials and Methods: Patients underwent FDG PET/CT and PSMA PET/CT imaging with a 24-hour interval be- tween studies. Two nuclear medicine physicians compared imaging findings. Results: Eight patients underwent FDG PET/CT and PSMA PET/CT images. In five patients, PSMA uptake was higher than FDG uptake. The highest PSMA uptake occurred in a giant cell recurrent sacral tumor of a 27-year-old male patient; the SUVs for PSMA and FDG were 100 and 16, respec- tively. A 58-year-old male patient with osteolytic metastasis from renal cell carcinoma in the right scapula presented PSMA uptake higher than FDG (SUVs = 40 and 11, respectively). A recurrent spin- dle cell neural tumor in the upper limb of a 69-year-old male presented PSMA uptake also higher than FDG (SUVs = 27 and 8, respectively). A myxofibrosarcoma mass in the distal right leg of a 61- year-old female presented higher PSMA uptake slightly higher than FDG uptake (SUVs = 18 and 10, respectively). Interestingly, two patients with chordomas had heterogeneous PSMA and FDG up- take. The PSMA PET/CT of a 65-year-old male patient presenting multiple metastases from chor- doma with soft tissue invasion showed uptake higher than FDG in all lesions; the highest SUV was a lesion in the right acetabulum: PSMA SUV = 32 and FDG SUV = 19. This patient presented PSMA-avid additional sites of metastases in mediastinal lymph nodes and the right hepatic lobe, while FDG uptake was minimal in these metastases. In contrast, an FDG PET/CT of a 54-year-old male with a large recurrent chordoma (30x24 cm mass) extending from the level of L4 to the proximal left thigh presented FDG uptake higher than PSMA uptake (SUVs = 31 and 9, respectively). Also, FDG uptake of two patients (52-year-old males) with desmoid tumors in the upper limb was higher than PSMA uptake, although uptake of both radiotracers was low: PSMA SUVs of 3 and 5, and FDG SUVs of 4 and 7. Conclusion: The study results show the potential advantage of using PSMA PET/CT and FDG PET/CT to provide additional information for monitoring patients and combining therapies, especially as PSMA PET/CT demonstrated more extensive disease. PSMA PET/CT has the advantage of the possi- bility of a Theranostic approach.
- Published
- 2024
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