Using Corticosteroids in Neoplasia

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
 

How reliable is the neurologic exam for patients with vestibular disease?

We (neurologists) like to think that the neurologic examination is the ultimate-be-all-end-all tool. But in dark corners, we talk about how incredibly hard it can be to do on patients with vestibular disease.
First, there are three parts that we need to consider for the lesion localization, correct?
1) Brainstem
2) Cerebellum
3) Peripheral CN 8
My rule of thumb is this: If the pet has ipsilateral hemiparesis/monoparesis, ipsilateral paw replacement deficits or decreased mentation (obtunded, stupor, coma) it is a brainstem lesion. If the pet has hypermetria, or intention tremors along with the vestibular signs, it is cerebellar in origin. Finally, in absence of those findings the lesion is localized peripherally.

An article out of Europe in 2019, dispelled our fears of the neurologic examination failing us and (thankfully) helped us sleep better at night when it was published that the neurologic examination correctly predicted if the vestibular signs were central (brainstem or cerebellum) or peripheral (cranial nerve 8) over 90% of the time.

Interestingly, central disease was more common in this study and, it was localized correctly MORE often than peripheral disease was localized correctly. In other words, dogs with central disease were more likely to be localized on the exam as having central disease compared to dogs with peripheral disease which were occasionally incorrectly localized with central disease.

A few more good reminders:

• Nystagmus are not a localizing sign! (E.g. 8 dogs with peripheral and 5 dogs with central disease had horizontal nystagmus.)

• The onset of disease does not predict it's lesion localization. (E.g. Acute and chronic onset of signs were not statistically different between the central and the peripheral groups.)

• They had a lot of French Bulldogs in the study! Huh..I'm not sure I've noticed an over representation of French Bulldogs in my clinical work. It's good to learn something new everyday.

So, what does that mean for us?

It means if you do a thorough neurologic exam, you'll be correct about 90% of the time when you guide a client towards an MRI and spinal tap (for central disease) or treat for idiopathic or otitis (for peripheral disease). If you're unsure, err on the side of it being a central lesion and recommend a full work up. (Or contact me for a consult!) Oh, and 68% of dogs diagnosed with peripheral vestibular were idiopathic! Idiopathic disease means we have a lot more to learn...so let's get back to it!

(Bongartz U, et al. Vestibular Disease in dogs: association between neurological examination, MRI lesion localization and outcome. JSAP 2019).

Thanks for reading! This was an oldie, but a goodie and I hope you enjoyed revisiting it along with me. Please reach out if you have any questions. Have a great week

Seizures are GOOD thing??

Brain tumors in adult dogs are relatively common. There are two primary brain tumor types in dogs: meningioma and glioma. Glial cell tumors are further divided into 3 subtypes varying from less aggressive to more aggressive in growth with rare metastasis. These tumors typically have a shorter long-term survival compared to meningiomas and are less surgically accessible. According to a recent study, dogs receiving palliative treatment have a median survival of about 1 month, compared to dogs receiving definitive treatment. Median survival for definitive treatment was almost 3 months.

This study looked at long-term survival using the new WHO classification scheme and found several interesting findings. The one that is most clinically applicable, and interesting to our pet population, is this:

Dogs with seizures as their first sign had a longer survival, regardless of histopathologic grade, than those with other neurologic signs at onset.

What does this mean? It means that, like in humans, seizures are like a warning shot, letting the rest of us know that something isn't right in the brain and we'd better take a look! If we proceed to MRI and make that diagnosis, dogs survive longer because of early onset palliative OR definitive therapy. This is yet another reason why we really should encourage clients to pursue a definitive diagnosis (i.e. brain MRI, spinal tap) even if they wouldn't consider definitive therapy such as surgery or radiation therapy. Early, aggressive, palliative medical care may actually prolong their dog's life beyond what we might get if we waited to "see what progressed".

I hope you have a good week and look forward to working with you, and your team, soon!

The full results of this study can be found at: https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.16199?campaign=wolearlyview