Page 1264 - Clinical Small Animal Internal Medicine

1202 Section 11 Oncologic Disease

Chemotherapy hormone secretion and appetite stimulation. This has
VetBooks.ir Fundamentally, local disease requires a treatment to be significant potential to treat inappetence related to
chemo therapy and/or underlying cancer in dogs and
directed to a specific area, typically surgery or radiation
therapy. Chemotherapy is often indispensable when pre- possibly cats. Maropitant citrate (Cerenia®) offers an eco-
nomical addition to the armament for the prevention
sented with widely disseminated but chemoresponsive and treatment of chemotherapy‐induced nausea and
disease (lymphoma) or when the development of meta- vomiting. In an effort to avoid chemotherapy related tox-
static disease is highly anticipated (canine osteosar- icity primarily found in herding breeds an assay is avail-
coma). The application, administration, and response able. These breeds have a higher risk of toxicity from
rates achievable through the use of chemotherapy are chemotherapeutic agents that are actively transported by
addressed in their respective chapters.
the p‐glycoprotein pump (e.g., vinca alkaloids, doxoru-
bicin, dactinomycin, taxanes). The assay is noninvasive,
Treatment Advances and is simply performed through either a blood sample
or cheek swab. For more information visit www.vetmed.
Recent treatment advances have provided the veteri- wsu.edu/depts‐vcpl/.
narian with orally administered targeted treatments
for mast cell tumors (Palladia™ and Kinavet‐CA1®).
TANOVEA®-CA1 (rabacfosadine) is the first FDA con- Surgery
ditionally approved drug for the treatment of lymphoma Surgical intervention is the backbone of localized cancer
in dogs. This drug is delivered intravenously and has treatment and is often used adjunctively in metastatic
been found to inhibit the proliferation of lymphoma cancers. Surgical oncology will be addressed in the
cells in vivo. Inter ventional radiology utilizes fluoros- respective chapters for which is applies.
copy and endoscopy, placing expandable metallic stents Interestingly, perioperative anesthetic and analgesic
in the urethra of dogs with neoplasia, resulting in practices, including administration of opioid analgesics
increased urine flow with tumor obstruction or near‐ and nonsteroidal antiinflammatory drugs (NSAIDs), use
obstruction. Chemoembolization refers to the angiog- of local anesthetic techniques, precipitation of the neu-
raphy guided administration of a vascular occluding roendocrine stress response, temperature regulation,
substance and chemotherapy through a catheter into a and transfusion of blood products may influence long‐
pinpointed vessel within the tumor. This technique has term outcomes such as recurrence and metastasis.
shown promise for the treatment of unresectable liver
tumors. Hematopoietic stem cell transplantation (HCT)
is available for dogs with hematopoietic malignancies. Radiation Therapy
Immunotherapy research collaboration has provided Radiation therapy (RT) utilizes the delivery of radiation
the first USDA‐approved canine melanoma vaccine from a distance. The delivery of radiation therapy in vet-
(Oncept®) indicated for aiding in extending survival of erinary medicine is through the use of three machine
dogs with stage II or stage III oral canine melanoma. types: orthovoltage (infrequently employed), cobalt‐60
Other available conditionally licensed vaccines include; (widely used), and linear accelerators (most common).
Canine Lymphoma Vaccine, a xenogeneic murine Pedestal machines are limited to up‐and‐down
CD20 DNA therapeutic vaccine for use in dogs with movement while isocentric machines rotate around the
B-cell lymphoma upon achieving remission through patient. The advantage permits treatment from a variety
chemotherapy. Canine Osteosarcoma Vaccine for the of angles. The prescribed radiation dose is expressed as
treatment of dogs one year or older diagnosed with tissue absorbed dose in units of gray (Gy). The total
appendicular osteosarcoma. The vaccine is a lyophi- prescribed radiation is delivered in small defined doses
lized formulation of a modified-live,attenuated, recom- called fractions. Radiation therapy is often employed
binant HER2/neu–expressing strain of Listeria that when surgical resection of a tumor is limited by normal
activates cytotoxic T cells. Lastly for our felines, Feline surrounding structures, and it is not possible to elimi-
Interleukin-2 (IL-2) Immunomodulator Vaccine may nate microscopic cells. In select cases when normal
delay postsurgical recurrence of feline fibrosarcoma in tissue structures preclude adequate surgical removal,
adult cats with stage I disease. radiation may be performed prior to surgery (preopera-
We have also had advancements in treatment‐related tive). The majority of radiation therapy is performed
side‐effects, with reports revealing protection from tis- 10–14 days postoperatively.
sue necrosis associated with administration of dexra- It is important that the radiation oncologist be aware
zoxane in patients with chemotherapy extravasation. of the original tumor site, including the dimensions and
Entyce®, capromorelin is an orally active small molecule extent of invasion, so as to include all the affected tis-
that mimics the action of ghrelin, which causes growth sue in the planned radiation field. When microscopic