Prognostic value of fluorine 18 flourodeoxyglucose positron emission tomography/computed tomography in dogs with appendicular osteosarcoma

BACKGROUND Factors indicative of a negative prognosis for appendicular osteosarcoma (OSA) in dogs are visible metastatic disease, location, and size of lesion. In human medicine maximum standard uptake value (SUVmax ), as measured on a fluorine18 flourodeoxyglucose positron emission tomography/computed tomography (18 F-FDG PET/CT), is prognostic for survival for several tumor types. OBJECTIVE Determine if SUVmax is associated with progression-free interval (PFI) and determination of survival in dogs with appendicular OSA. ANIMALS Sixty-two dogs with untreated appendicular OSA that had been staged with 18 F-FDG PET/CT. METHODS Retrospective analysis of the 18 F-FDG PET/CT was performed. Dogs were excluded from the study if they did not receive definitive intent treatment for their primary OSA and adjuvant chemotherapy with carboplatin, or had visible metastatic disease on initial imaging. A region of interest (ROI) was created around the primary tumor to measure SUVmax . Univariable and multivariable Cox proportional hazards analysis was performed to evaluate for associations between variables including SUVmax and outcome of PFI and overall survival (OS). RESULTS Maximum standard uptake value of the primary tumor was significantly associated with the OS (P = .04) with adjustment for treatment type and monocyte count. The overall median survival time (OST) was 284 days (range, 39-1293 days) with the OST of dogs having an SUVmax of ≥7.4 of 254 days (range, 98-428 days) and dogs with an SUVmax of