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

Abstract

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 (18F‐FDG PET/CT). In this retrospective study dogs afflicted with appendicular osteosarcoma that were staged with 18F‐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 18F‐FDG PET/CT results.

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

“…The lack of association between the survival of canine patients afflicted with appendicular OSA and the SUV max1 , MTV 1 , and TLG 1 obtained from the initial images is in conflict with previous studies showing the prognostic potential of 18 F‐FDG PET/CT in these cases 24,25 . Some of this may be due to the small numbers evaluated, but some selection bias may exist as these patients were chosen for admittance to the study based upon evaluation of pre‐study imaging that they would not fracture prior to the EoT PET imaging, obtained 3 months after the initiation of treatment.…”

“…The lack of association between the survival of canine patients afflicted with appendicular OSA and the SUV max1 , MTV 1 , and TLG 1 obtained from the initial images is in conflict with previous studies showing the prognostic potential of 18 F-FDG PET/CT in these cases. 24,25 Some of this may be due to the small numbers evaluated, but some selection bias may exist as these patients were chosen for admittance to the study based upon evaluation of pre-study imaging that they would not fracture prior to the EoT PET imaging, obtained 3 to be significantly shorter in patients who develop a pathologic fracture if the owners do not elect for amputation. 26 Those dogs that do not develop a pathologic fracture may go on to have prolonged survival, making it important to be able to identify risk for metastatic disease and assess response to treatment.…”