Page 1314 - Clinical Small Animal Internal Medicine

1252 Section 11 Oncologic Disease

Spinal Cord Hydroxyurea is an alkylating agent most commonly
VetBooks.ir described in the veterinary literature but studies are lim- used in veterinary medicine for the management of poly-
Radiation therapy of spinal cord tumors has been
cythemia. Recently, it has been used as an adjuvant to
ited by low case numbers and lack of histopathologic
nial and spinal meningioma. In one such study, oral
confirmation in the majority of patients. As with intrac- surgery and/or radiation therapy for dogs with intracra-
ranial irradiation, a similar limitation of dose is encoun- hydroxyurea in combination with glucocorticoids was
tered in the spinal cord and control times are affected by administered to 33 dogs with MRI‐diagnosed meningi-
the spinal cord tolerance. oma, resulting in a significantly longer survival time than
In one study, primary radiation therapy for spinal cord observed in 10 dogs treated with glucocorticoids alone.
tumors (no histopathologic confirmation) resulted in Temozolamide has recently been evaluated in man-
median control of nine months. In a separate study eval- agement of canine glial tumors. Although the data in
uating surgery for spinal meningioma, those that under- veterinary oncology are preliminary and no strong
went postoperative radiation therapy appeared to have a recommendations can be made regarding efficacy and
benefit based on time to neurologic deterioration but comparison with other chemotherapy approaches
recurrence of signs and/or tumor recurrence was noted cannot be made, results in the human literature are
anywhere from 18 to 36 months. It is important to recall encouraging.
that deterioration of neurologic condition may be related For patients with CNS lymphoma, options in addition
to tumor recurrence but may also be related to spinal to standard chemotherapy include lomustine, hydroxyu-
cord damage/necrosis. Therefore, documentation of rea, and the antimetabolite cytosine arabinoside which
true tumor recurrence is recommended prior to consid- cross the blood–brain barrier. The role of chemotherapy
ering repeat irradiation and/or surgical intervention. specifically for spinal cord neoplasia is not known, but
similar chemotherapeutics are recommended depending
on final diagnosis when possible.
Chemotherapy
There is very little in the veterinary literature regarding
chemotherapy for CNS neoplasia with the exception of Newer Therapies
standard chemotherapy for canine and feline lymphoma. With increased understanding of how the immune sys-
The blood–brain barrier represents a significant obsta- tem functions in tumor environments, immunotherapy,
cle to the delivery of chemotherapy to the brain and spi- in particular tumor vaccination and gene therapy,
nal cord. Survival times of dogs with unconfirmed (no has recently been developed to aid in the treatment
biopsy) brain tumors treated with lomustine (CCNU) of canine brain tumors but these approaches remain
were very similar to patients treated with supportive care investigational.
alone (93 vs 60 days).

Further Reading

Dickinson PJ. Advances in diagnostic and treatment LeBlanc AK, Mazcko C, Brown, et al. Creation of an NCI
modalities for intracranial tumors. J Vet Intern Med comparative brain tumor consortium: informing the
2014; 28(4): 1165–85. translation of new knowledge from canine to human
Hicks J, Platt S, Kent M, Haley A. Canine brain tumours: a brain tumor patients. Neuro Oncol 2016; 18(9): 1209–18.
model for the human disease? Vet Comp Oncol 2017; Van Meervenne S, Verhoeven PS, de Vos J, Gielen IM.
15(1): 252–72. Comparison between symptomatic treatment and
Hu H, Barker A, Harcourt‐Brown T, Jeffery N. Systematic lomustine supplementation in 71 dogs with intracranial,
review of brain tumor treatment in dogs. J Vet Intern space‐occupying lesions. Vet Comp Oncol 2014; 12(1):
Med 2015; 29(6): 1456–63. 67–77.