Dynamic contrast-enhanced magnetic resonance imaging as a predictor of clinical outcome in canine spontaneous soft tissue sarcomas treated with thermoradiotherapy.
OBJECTIVE
This study tests whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters obtained from canine patients with soft tissue sarcomas, treated with hyperthermia and radiotherapy, are predictive of therapeutic outcome.


METHODS
Thirty-seven dogs with soft tissue sarcomas had DCE-MRI done before and following the first hyperthermia. Signal enhancement for tumor and reference muscle were fitted empirically, yielding a washin/washout rate for the contrast agent and tumor area under the signal enhancement curve (AUC) calculated from 0 to 60 seconds, 90 seconds, and the time of maximal enhancement in the reference muscle. These parameters were then compared with local tumor control, metastasis-free survival, and overall survival.


RESULTS
Pretherapy rate of contrast agent washout was positively predictive of improved overall and metastasis-free survival with hazard ratio of 0.67 (P = 0.015) and 0.68 (P = 0.012), respectively. After the first hyperthermia washin rate, AUC60, AUC90, and AUCt-max were predictive of improved overall and metastasis-free survival with hazard ratio ranging from 0.46 to 0.53 (P < 0.002) and 0.44 to 0.55 (P < 0.004), respectively. DCE-MRI parameters were compared with extracellular pH and (31)P MR spectroscopy results (previously published) in the same patients showing a correlation. This suggested that an increase in perfusion after therapy was effective in eliminating excess acid from the tumor.


CONCLUSIONS
This study shows that DCE-MRI has utility predicting overall and metastasis-free survival in canine patients with soft tissue sarcomas. To our knowledge, this is the first time that DCE-MRI parameters are predictive of clinical outcome for soft tissue sarcomas.
Viglianti
Benjamin L
BL
Departments of Radiation Oncology, Biostatistics and Bioinformatics, and Radiology, Duke University Medical Center, Durham, NC 27710, USA.
Lora-Michiels
Michael
M
Poulson
Jeanie M
JM
Lan
Lan
L
Yu
Daohai
D
Yu
Dahio
D
Sanders
Linda
L
Craciunescu
Oana
O
Vujaskovic
Zeljko
Z
Thrall
Donald E
DE
Macfall
James
J
Charles
Cecil H
CH
Wong
Terence
T
Dewhirst
Mark W
MW
D000818:Animals; D003131:Combined Modality Therapy / Q000662:veterinary; D004283:Dog Diseases / Q000175:diagnosis*; D004285:Dogs; D006979:Hyperthermia, Induced / Q000662:veterinary; D007089:Image Enhancement; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000662:veterinary*; D011379:Prognosis; D011878:Radiotherapy / Q000662:veterinary; D011879:Radiotherapy Dosage / Q000662:veterinary; D012509:Sarcoma / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D012983:Soft Tissue Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D016896:Treatment Outcome