Prospective pilot study utilizing changes in quantitative values obtained on serial fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET/CT) in dogs with appendicular osteosarcoma before and after stereotactic body radiation therapy (SBRT) and carboplatin chemotherapy to assess for prediction of survival and therapeutic effectiveness

Tiffany W Martin; Lynn Griffin

doi:10.1111/vru.13361

Prospective pilot study utilizing changes in quantitative values obtained on serial fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography-computed tomography (PET/CT) in dogs with appendicular osteosarcoma before and after stereotactic body radiation therapy (SBRT) and carboplatin chemotherapy to assess for prediction of survival and therapeutic effectiveness

Vet Radiol Ultrasound. 2024 Apr 24. doi: 10.1111/vru.13361. Online ahead of print.

Authors

Tiffany W Martin¹, Lynn Griffin²

Affiliations

¹ Department of Clinical Sciences, Flint Animal Cancer Center, Colorado State University, Fort Collins, Colorado, USA.
² VCA Canada Central Victoria Veterinary Hospital, Victoria, British Columbia, Canada.

PMID: 38655687
DOI: 10.1111/vru.13361

Abstract

Serial fluorine 18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography-CT (PET/CT) is commonly used in human oncology to prognosticate and evaluate for therapeutic effectiveness. In this pilot study, dogs with naturally occurring appendicular osteosarcoma were evaluated with serial ¹⁸F-FDG PET/CT in an attempt to assess for response to therapy, prognostic factors, and appropriateness of imaging intervals. Fourteen dogs were enrolled in the trial. All dogs had the initial ¹⁸F-FDG PET/CT (PET1), with nine dogs having their end-of-therapy ¹⁸F-FDG PET/CT (EoT PET) 3 months after stereotactic body radiation therapy (SBRT) to the primary tumor. The median percent change from the PET1 to the EoT PET for the standard uptake value maximum (SUV_max%) was -58% (range: -17 to -88%), metabolic tumor volume (MTV_%) was -99.8% (range: -65 to -100%), and total lesion glycolysis (TLG_%) was -99.8% (range: -75 to -100%), all of which were significant (P < .05, <.05, and <.05, respectively). On evaluation, it was found that volumes of GTV and CTV were significant for survival (P < .05 and <.05), MTV₁, TLG₁, and SUV_max on the EoT PET (SUV_maxEoT) were predictive of metastasis (P < .05), and the SUV_max% was significantly correlated to the time to first event (P < .05). Based on this data, serial ¹⁸F-FDG PET/CT performed 3 months after SBRT can show a significant reduction in avidity, and the quantitative data collected may help predict metastatic disease in canine appendicular osteosarcoma.

Keywords: bone; canine; limb; radiotherapy; response.