• Oncology Quarterly

Oncology Quarterly
Volume 2 Winter 2007
Corky and Kaylee Smith
For Richard and Monica Smith, it started variable rates of metastasis, with the risk of
simply as a small area of hair loss on their eight year- metastasis being largely dependent on the histologic
old Shetland Sheepdog, Corky’s, left tarsus. Two days grade. Because Corky’s tumor was a grade 1, there was
later, the spot had grown into a small mass and by the only about a 10% risk of metastatic spread. The
end of the week, it was the size of a golf ball. Smiths chose to pursue radiation therapy.
Understandably concerned, the Smiths consulted their In Corky’s case, his radiation protocol
veterinarian and had the mass removed. The histopa- consisted of 19 treatments of daily radiation, each
thology report described the mass as a low-grade delivered under general anesthesia. With this
(grade 1) hemangiopericytoma. The tumor was regimen, it is expected that greater than 80 to 90%
incompletely removed, a common problem with masses of patients will not have recurrence within 3 to 5
on the extremities where insufficient tissue is present years. Because of Corky’s close attachment to his sis-
for complete surgical resections. ter Kaylee, the Smiths decided to have both Corky and
Corky was referred to the OSU Medical Kaylee stay at OSU during Corky’s therapy.
Oncology service to stage his disease and pursue As expected with this protocol, Corky did
additional treatment options. Thoracic radiographs develop side effects, moist desquamation of the skin,
and fine needle aspirates of his left popliteal lymph in the treatment area, a region three centimeters
node showed that the tumor had not spread to these around his scar. The moist desquamation began during
locations. Now the focus of treatment was addressing the last week of treatment and lasted for about three
the microscopic disease that remained at the surgical weeks. The affected area was treated with
site. Potential treatment options considered included antibiotics, pain medications, and an E-collar to keep
local infiltration with chemotherapy, radiation him from licking the site.
therapy and amputation. Today, nearly 21 months after his treatment,
Hemangiopericytomas, or peripheral nerve Corky is feeling great. He visits his veterinarian
sheath tumors, are generally slow growing tumors with regularly for routine reevaluation of the radiation site
and has no evidence of tumor regrowth.
Additional tumors for which radiation therapy may
play a beneficial role in treatment:
Soft Tissue Sarcomas, Brain Tumors, Oral tumors
(Squamous Cell Carcinoma, Melanoma, Fibrosarcoma),
Mast Cell Tumors, Osteosarcoma, and Nasal Tumors
Above: Corky (left) and Kaylee (right) Smith, 21 months after
treatment. Right: Healing moist desquamation on Corky’s limb.
1
 Artemisinin and its Role in Cancer Treatment
The Oncology/Hematology Service recently similar ability for artemisinin to induce cell
began a new clinical trial, investigating the death in several types of canine cancer cells in
pharmacokinetics of high-dose intermittent vitro. Artemisinin has been used to a limited
oral artemisinin in dogs with spontaneous extent for clinical cancer treatment in people
tumors. Dr. Kenji Hosoya, resident in Radiation and anecdotally in dogs with osteosarcoma, with
Oncology, investigated the effects of daily administration of small doses. However,
artemisinin on cancer cells in culture. Due to there are few reports of successful outcomes.
his laboratory findings, we are now investigat- Studies of continuous oral artemisinin
ing the use of artemisinin for the treatment of administration revealed a remarkable time-
tumors in dogs. dependent decrease in bioavailability that
What is artemisinin? Artemisinin is an occurs within 7 days. The currently used dose
extract from the plant Artemisia annua L., of artemisinin for cancer patients seems
which is used in traditional Chinese medicine inappropriately low compared to the potentially
(TCM). It was first identified and isolated in needed target plasma concentration, based on
1972 in a project to discover new antimalarial in vitro data collected by Dr. Hosoya.
drugs from TCM launched by the Chinese The current on-going clinical trial will in-
government and now is the first-line treatment vestigate if the absorption resistance can be
for malaria in South Asia. avoided by pulse-dosing artemisinin and will also
Artemisinin also has been shown to have evaluate the therapeutic effects of artemisinin
toxic effects in several types of human cancer in tumor-bearing dogs.
cells in vitro. Dr. Hosoya has demonstrated a
Clinical Trials
On-Going Clinical Trials
• Gene expression profiling of canine
lymphoma
• Oral artemisinin in dogs with spontane-
ous tumors
Above: Cytology of
transitional cell carcinoma • Copy number polymorphisms in dogs
Above, right: Leaf from the • DNA methylation in canine lymphoma
Artemisia annua plant. • Rapid release paclitaxel particles for
Right: Cytology of lymphoma intravesical treatment of transitional
Below: Chemical structure of
cell carcinoma
artemisinin.
Upcoming Clinical Trials
• Evaluation of Rapamycin (a mTOR
inhibitor) in dogs with osteosarcoma
2
 Radiation Oncology
Radiation therapy is the use of high-energy
radiation from x-rays, gamma rays, neutrons,
and other sources to kill cancer cells and shrink
tumors. Radiation may come from a machine or
from materials placed in the body. At The Ohio
State University, a linear accelerator is used to
deliver radiation treatments. This is the
equipment most commonly used in human
medicine. It delivers a uniform dose of high-
energy x-rays to the targeted area of the
patient. The radiation can be delivered to the
patient’s tumor from any angle in an attempt to
avoid excessively irradiating normal tissue. The
radiation kills tumors cells and shrinks tumors Radiation therapy in dogs and cats typically
that may not be affected by chemotherapy or does not cause any systemic side effects such
safely removable by surgery. It does this by as nausea or decreased appetite. Some patients
damaging the DNA of the tumor, causing the may experience fatigue due to repeated
tumor cells to die. Radiation therapy often is anesthesia. Direct side effects of the radiation
used in conjunction with chemotherapy and/or at the treatment site are more common. Acute
surgery. side effects are those effects that occur
Radiation treatments are either definitive shortly after the treatment is over and can be
or palliative in their intent. Definitive therapy expected with definitive protocols. They occur
is given in a course of treatments that can last in tissues within the treatment field and are
2-4 weeks, depending on the tumor type. This due to the death of rapidly dividing normal cells
schedule delivers a large total radiation dose to like skin and mucous membranes. These side
the tumor in many small fractions, each given effects are generally managed conservatively
once a day. This helps to protect normal with antibiotics and pain medications and heal
healthy tissue from being excessively damaged. on their own within 2 to 3 weeks. Late effects
Palliative therapy is designed to relieve cancer are those that occur well after the conclusion
related discomfort or pain in the patient with of radiation therapy and are usually related to
disease when the likelihood for definitive death of the endothelial cells (those cells lining
control is low. Treatment is typically given once blood vessels). This results in side effects
a week for four weeks and rarely causes any that are specific to the tissues in the
side effects. treatment field (osteoradionecrosis, fibrosis,
demyelination, etc…). Late effects are more
likely to occur when palliative protocols are
used, so these protocols are reserved for
patients where long-term survival is not likely.
Article written by Dr. Eric Green
.
Right: Computer generated image used for mapping
targeted area for treatment.
Above: Patient undergoing treatment in the linear
accelerator
3
 What is Your Diagnosis?
Signalment:
A female, 7-year-old Pitbull
Terrier presented to the
Surgery Service for evaluation
of an ulcerated mass of the pinna
of her left ear. The mass was
removed and sent for
histopathology.
Above: Representative cytology from a fine needle
aspirate (FNA) of the tumor. Wright’s-Giemsa, 100X
Below: Histopathology of the ear mass. H&E, 10 X
Left: Histopathology of the ear mass. H&E, 40 X
A
What is your cytologic and
histologic description?
What is your diagnosis?
The answers are on the next page.
4
Diagnosis: Hemangiopericytoma
Cytologic description: Large aggregates of spindle to stellate shaped cells. Moderate to abundant,
lightly basophilic cytoplasm with indiscreet cytoplasmic borders or veiling appearance. The nuclei
are round to oval with a coarse chromatin pattern. One to many small prominent nucleoli.
Histopathologic description: Poorly demarcated sheets of moderately pleiomorphic spindle cells
that occasionally form perivascular whorls.
Review of Hemangiopericytomas
Hemangiopericytomas are common malignant Treatment options include radical surgery
tumor of subcutaneous origin in dogs. This tumor with complete margins, marginal surgery with
is a member of the soft tissue sarcoma family. adjuvant radiation therapy, or infiltrating the site
This family of tumors is a diverse group of tumors, with local chemotherapy. Long term control is
which comprise about 15% of all skin and usually achievable with Grade 1 and 2
subcutaneous tumors. They are most often found hemangiopericytomas.
on the extremities but can occur anywhere.
These tumors have a low incidence of
metastasis but the rate is dependent on histologic
grade. They are known to be locally aggressive
and often locally recur. As with all soft tissue
sarcomas ,staging prior to treatment is important.
This should consist of three view thoracic
radiographs and regional lymph node assessment
with either FNA or biopsy.
Histology is important for assessing risk for
metastasis and evaluating surgical margins.
Grades 1 or 2 tumors have a 10% to 20% rate of
metastasis. Grade 3 tumors have a much higher
metastatic rate, but are relatively uncommon.
For information on the Clinical Trials please contact, Jill Yaissle, DVM, MS (yaissle.1@osu.edu) or
for information concerning the Greyhound Program please contact, Liliana Marin, DVM
(marin.25@osu.edu) at (614) 292-0950.
Appointments for Medical Oncology are scheduled by calling OSU-VTH at (614) 292-3551, please
ask for any other following individuals:
Stacey Gallant, RVT; Nicole Westendorf, RVT; Janet Charske, RVT
Appointments for Radiation Oncology are scheduled by calling OSU-VTH at (614) 292-3551.
Please ask for Eric Green, DVM, DACR (Radiology and Radiation Oncology).
WEBSITES:
Oncology/Hematology: vet.osu.edu/564.htm; Blood bank: vet.osu.edu/bloodbank.htm
Chemotherapy Protocols: vet.osu..edu/1359.htm; Greyhound Information: vet.osu.edu/1872.htm
You can be part of improving animals’ lives through your generous donation. For information about giving to
these and other programs please contact Karen Longbrake, Director of Development at (614) 688-8433 or
Longbrake.1@osu.edu.
5