The prognostic significance of metabolic tumour volume and total lesion glycolysis for dogs staged for appendicular osteosarcoma with fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography.

Metabolic tumour volumes (MTV) and total lesion glycolysis (TLG) are metabolic parameters that are becoming more commonly reported in human medicine to quantify tumours detected on fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18 F-FDG PET/CT). In this retrospective study dogs afflicted with appendicular osteosarcoma that were staged with 18 F-FDG PET/CT had MTV and TLG at a variety of set and fixed thresholds calculated by two observers. These values, along with SUVmax , were evaluated for prognostic significance in this population of dogs. There was excellent correlation between two observers for all values. Multiple volumetric parameters were significantly associated with survival. SUVmax had the highest sensitivity for survival and TLG at 2.5 SUV*cm3 had the highest specificity for prediction of survival based on ROC calculations. The SUVmax , MTV at 2.5 SUV and TLG at 2.5 SUV*cm3 were significantly different between dogs that survived more than or less than 1 year. This study is the first of its kind in veterinary medicine that retrospectively evaluated volumetric tumour values for prognostic significance and may provide a basis for standardized method of reporting 18 F-FDG PET/CT results.