Corticosteroids have long been the mainstay treatment for dogs and cats with MRI diagnosed neoplasia. Approximately 85% of brain tumors demonstrate peritumoral edema (PTE) so it stands to reason that corticosteroids would reduce this edema. A recent study set out to determine the clinical response as well as the MRI response to corticosteroid use in dogs with suspected glial cell tumors or meningiomas. The dose of corticosteroids was not consistent or controlled in the study, nor was the use of anticonvulsants.
Materials and Methods
Seventy-two dogs were included in the retrospective study. Dogs were diagnosed with a glioma or meningioma on MRI, which was later confirmed with histopathology. They were then administered prednisone or prednisolone and a second MRI within 3 weeks of the initial MRI. At the second MRI, a quality of life questionnaire was provided to the owners.
50/72 glioma – a mix of oligodendroglioma, astrocytoma and unclassified glioma along with a mix of grades.
45/90 were in a cerebral hemisphere (90%)
22/72 meningioma – most were grade I tumors, but a few were grade II.
10/22 (45%) were in cerebral hemispheres
Results
A total of 38/72 (53%) were classified as clinical responders, and 34/72 (47%) were classified as clinical non responders. The most common clinical signs to improve were proprioceptive deficits, central visual deficits and other gait abnormalities.
A total of 23/50 (46%) of dogs with glioma and 14/22 (64%) of dogs with meningioma had detectable decreases in peritumoral brain edema volume. A significant difference in total tumor volume and contrast enhancing tumor volume was noted between responders and non-responders with glioma. This was not observed with meningiomas.
Discussion
This study outlines what we had long suspected: corticosteroids can improve quality of life and neurologic signs in dogs with glioma and meningioma brain tumors. What we didn’t know, and what this study showed, was a detectable decrease in measurable tumor volume with the use of corticosteroids. Did it work for everyone? No. Can it help? Yes, about 50% of dogs improved and no major adverse effects were noted from administration of the medications. Another little tidbit that I found interesting from this study was that among non-responders, 42% of dogs with glioma and 72% of dogs with meningiomas had seizures as their only clinical signs. This is in contrast to responders in which only about 10% of dogs had seizures as their only clinical sign. Another interesting finding was that 2 dogs, classified as clinical non responders, showed a 50% decrease in peritumoral brain edema. This means that the tumor was a bigger deal than the edema in these dogs. Location, location, location, I suppose.
Clinical Key Points:
Corticosteroids, such as prednisone or prednisolone should be considered part of the palliative care package for dogs with glioma or meningioma.
Dogs with meningiomas and seizures as their only clinical sign may have a poorer response to corticosteroids compared to dogs with other neurologic deficits,
I hope you enjoyed this week’s TidBit Tuesday. Let me know if you have any questions or saw a recent article that you think we should review. Have a great week!
Reference: doi.org/10.1111/jvim.70126