Page 1294 - Small Animal Internal Medicine, 6th Edition

1266 PART XII Oncology

BOX 75.1 ensures that the interaction with the owner is smooth and
uneventful. As discussed in later paragraphs, the option of
VetBooks.ir Treatment Options for Animals With Cancer euthanasia may also be addressed at this time, either as an
immediate option or eventual option if treatments fail.
Surgery
Another important owner-related factor is finances. In
Radiotherapy general, the treatment of a cat or dog with disseminated or
Traditional chemotherapy metastatic malignancy is relatively expensive, as judged by
Metronomic chemotherapy
Targeted molecular therapy the average clinician. However, it is the owner who should
Immunotherapy (biologic response modifiers) determine whether this treatment is indeed too costly. It is
Hyperthermia relatively common for an owner to spend $5000 to $10,000
Cryotherapy to treat a dog or cat with surgery, radiotherapy, or chemo-
Phototherapy therapy. In contrast, a common orthopedic surgical proce-
Photochemotherapy dure (e.g., tibial plateau leveling osteotomy) costs $2500 to
Electrochemotherapy $4000. Therefore all treatment options should be described
Thermochemotherapy and offered to the pet family, regardless of their cost. Occa-
Unconventional (alternative) sionally, families spend what most people consider to be
exorbitant amounts of money to treat their pet with cancer
or other diseases. As numerous owners explain, this is their
TABLE 75.1 family member, and it is their money!

Modified Karnovsky’s Performance Score for
Dogs and Cats TREATMENT-RELATED FACTORS

GRADE ACTIVITY/PERFORMANCE
Several important treatment-related factors must be consid-
0—Normal Fully active, able to perform at ered when planning cancer therapy. First, the specific indica-
predisease level tion should be considered. Surgery and radiotherapy are
1—Restricted Restricted activity from treatments aimed at eradicating a locally invasive tumor with
predisease level but able to a low metastatic potential (and potentially curing the
function as an acceptable pet patient), although they can be used palliatively in dogs or
2—Compromised Severely restricted activity level; cats with extensive (bulky) disease or in those with meta-
ambulatory only to the point static disease. On the other hand, chemotherapy usually does
of eating but consistently not constitute a curative treatment, although palliation of
defecating and urinating in advanced disease can easily be accomplished for several
acceptable areas tumor types. Immunotherapy (the use of biologic response
3—Disabled Completely disabled; must be modifiers) also constitutes an adjuvant or palliative approach
force-fed; unable to confine (i.e., tumors are rarely cured by immunotherapy alone).
urinations and defecations to Recently, targeted molecular therapy has been aimed at
acceptable areas blocking specific pathways present in neoplastic but not
4—Dead normal cells. In general, it is best to use an aggressive treat-
ment when the tumor is first detected (because this is when
Modified from Beveridge IB, Sobin LH: International histological the chances of eradicating every single tumor cell are the
classification of tumors of domestic animals, Bull World Health highest) rather than to wait until the tumor is in an advanced
Organ 53:145, 1976. stage (i.e., to “treat big when the disease is small”). Removing
“only” 99% of the tumor cells will not lead to a cure.
assume responsibility for the fate of their pet and are there- In some cases, the highest success rates are obtained by
fore quite cooperative. The clinician should always be avail- combining two or more treatment modalities. For example,
able to answer concerned pet owners’ questions and guide the combination of surgery and chemotherapy has resulted
them through difficult times. We always discuss all potential in a significant prolongation of disease-free survival in dogs
treatment options with the owner, emphasizing the pros and with osteosarcoma of the appendicular skeleton (4 months
cons of each (e.g., beneficial effects and potential for adverse with surgery alone versus 12-18 months with surgery and
effects of treatment A versus B versus C versus no treatment). chemotherapy).
The authors also clearly explain what will (or should) happen The complications and adverse effects of different treat-
during the pet’s treatment, including a thorough descrip- ments also constitute treatment-related factors to be consid-
tion of the potential adverse effects by presenting different ered when planning therapy. Complications of chemotherapy
case scenarios (i.e., best-case scenario versus worst-case sce- are addressed in Chapter 77. As discussed later, the patient’s
nario). By observing these easy steps, the clinician usually QOL should be maintained (or improved) during cancer
cultivates realistic expectations on the part of the owner and treatment. At the authors’ clinic, this is the priority in a cat