The use of fluorine‐18‐fluorodeoxyglucose‐positron emission tomography/computed tomography as an effective method for staging in dogs with primary appendicular osteosarcoma

Abstract

Fluorine-18-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) has been utilized in veterinary medicine to improve the detection and characterization of primary, recurrent, and secondary neoplasms; but its use as a staging tool for dogs diagnosed with appendicular osteosarcoma has not been published. The purpose of this retrospective, case series, descriptive study was to detail the use of 18 F-FDG PET/CT for staging a population of dogs with appendicular osteosarcoma, report the detection rate of secondary neoplastic lesions, and compare findings with published detection rates for other historically used imaging modalities.Seventy-one client-owned dogs with a confirmed diagnosis of appendicular osteosarcoma and staged with a whole-body 18 F-FDG PET/CT scan near the time of initial diagnosis were included. Each PET/CT study was re-evaluated for malignancy distinct from the primary disease entity based on a collective qualitative and quantitative assessment of 18 F-FDG uptake, CT appearance, and contrast enhancement characteristics.Following re-evaluation of each study, information pertaining to tissue sampling performed on identified lesions was retrieved from the medical record when available.Staging with 18 F-FDG PET/CT identified 17 of 71 (23.9%) and 12 of 71 (16.3%) dogs with a high suspicion or confirmation of a metastatic or comorbid malignant neoplasm respectively, with eight of 71 (11.3%) having both metastatic and comorbid lesions. The results of this study are suggestive that 18 F-FDG PET/CT is effective in identifying both osseous and soft tissue secondary neoplastic lesions in dogs afflicted with appendicular osteosarcoma, yielding an increased detection rate of all lesions compared those previously reported for skeletal scintigraphy or whole-body CT.

Staging canine patients with appendicular osteosarcoma utilizing fluorine‐18 fluorodeoxyglucose positron emission tomography/computed tomography compared to whole body computed tomography

“…1,2 Due to the high metastatic rate seen with osteosarcoma, appropriate staging of patients prior to treatment is imperative to help determine prognosis and best therapeutic recommendations. [2][3][4] Treatment is often based on a multimodal approach, incorporating surgery, chemotherapy and/or radiation therapy. 5 Traditionally, modalities for staging canine patients with appendicular osteosarcoma have included thoracic radiographs and/or thoracic computed tomography (CT) for assessing for pulmonary metastasis and nuclear scintigraphy for detecting osseous lesions.…”

“…Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) has recently been incorporated into staging protocols at our institution. 4 In human paediatric studies, 18 F-FDG PET/CT has been found to have higher sensitivity, specificity and diagnostic accuracy compared to bone scintigraphy in identifying distant bone metastases in patients with osteosarcoma. 6 The utility of 18 F-FDG PET/CT for staging canine patients with appendicular OSA has only recently been reported, 4 however a direct comparison to other imaging modalities…”

“…4 In human paediatric studies, 18 F-FDG PET/CT has been found to have higher sensitivity, specificity and diagnostic accuracy compared to bone scintigraphy in identifying distant bone metastases in patients with osteosarcoma. 6 The utility of 18 F-FDG PET/CT for staging canine patients with appendicular OSA has only recently been reported, 4 however a direct comparison to other imaging modalities…”

“…As most malignant lesions are highly metabolically active, neoplastic cells often have higher levels of FDG uptake than surrounding tissues. 4,[8][9][10] The maximum standardized uptake value (SUV max ) is a commonly used semiquantitative measurement of the amount of FDG uptake, or avidity, within a specific anatomic region. SUV max is indicative of the highest voxel of metabolic activity within a defined region of interest (ROI).…”

“…4,9,10 In veterinary medicine, 18 F-FDG-PET/CT has been shown to be an effective staging tool for patients with several different neoplasms, including lymphoma, mast cell tumour, mammary carcinoma, primary lung tumour, histiocytic sarcoma, Sertoli cell tumour and splenic hemangiosarcoma. 7,[11][12][13][14][15] Initial research has also shown that 18 F-FDG-PET/CT is effective for identifying both osseous and soft tissue lesions in dogs afflicted with appendicular osteosarcoma 4 and that the SUV max of the primary lesion is significantly associated with survival time. 10 However, the efficacy of 18 F-FDG-PET/CT has yet to be directly compared to other staging modalities.…”