Page 21 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

xx Introduction

advance veterinary-based practice and inform future human clini- 14. The elucidation of the canine genome and its resemblance
cal trials that may follow. Some of the aspects of companion ani- and relevance to the human genome open unique and unpar-
alleled opportunities to study comparative oncology from a
mal cancer that enable attractive comparative models include the
VetBooks.ir following: Clients who seek treatment for their companion animals with
9
genetic perspective.
1. Companion dogs and cats are genetically outbred (like hu-
mans), as opposed to many experimental models of rodents cancer are a devoted and compassionate subset of the population.
and other animals. Working with these caregivers can be a very satisfying aspect of a
2. The cancers seen in practice are spontaneously developing as frequently frustrating specialty. Clients are almost always satisfied
opposed to experimentally induced and better recapitulate with an honest and aggressive attempt to cure, control, or palliate
the natural human and veterinary condition. the disease of their companion, making the experience satisfying
3. Companion species share the same environment as their for the veterinarian, for the client, and, most important, for the
caregivers and may serve as epidemiologic or etiologic senti- companion.
nels for the changing patterns of cancer development seen in Oncology also offers the inquisitive veterinarian a complex and
humans. challenging area for both clinical and basic research. The challenges
4. Companion species have a higher incidence of some cancers and accomplishments in oncology have been and continue to be
(e.g., osteosarcoma, non-Hodgkin lymphoma) than humans. very impressive. Oncology offers unlimited opportunity for the
5. Most animal cancers will progress at a more rapid rate than pursuit of knowledge for the benefit of animals and humankind.
will the human counterparts. This permits more rapid and “Cancer, unlike politics and religion, is not a topic of controversy.
less costly outcome determinations such as time to metasta- No one is for it. Cancer is not another word for death. Neither is it
sis, local recurrence, and survival. a single disease for which there is one cure. Instead, it takes many
6. Because fewer established “gold standard” treatments exist in forms, and each form responds differently to treatment”. 10
veterinary medicine compared with human medicine, it is Clinical and comparative oncology continues to be a rapidly
ethically acceptable to attempt new forms of therapy on an advancing field of study. More training programs are developed
untreated cancer rather than wait to initiate new treatments each year that allow a wider distribution of experienced veterinar-
until all “known” treatments have failed, as is common in ians into practice, research, industry, government, and the aca-
the human condition. It is important to recognize that this demic setting. Through the continued investigation of tumor
latitude in clinical trials can be misused to permit diverse biology and treatment and the inclusion of veterinary species in
and poorly characterized or even unethical treatments to be well-designed, rigorous, and humane clinical trials, the veterinary
attempted as well. We have an obligation to ensure that our profession will play a key role in advancing the diagnosis, treat-
patients are not denied known effective treatment while at ment, and prevention of cancer for all species.
the same time planning well-designed prospective clinical tri-
als of newer, scientifically sound treatment methods. David M. Vail, Douglas H. Thamm, and Julius M. Liptak
7. Companion species’ cancers are more akin to human cancers
than are rodent tumors in terms of patient size and cell kinet- References
ics. Dogs and cats also share similar characteristics of physi-
ology and metabolism for most organ systems and drugs. 1. American Pet Products Association 2011-2012 National Pet Owners Survey.
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8. Dogs and cats have intact immune systems as opposed to 3. Animal Health Survey: In Companion animal news, Englewood, CO, 1998,
many rodent model systems, which allows immunologic Morris Animal Foundation, 2005.
assays and treatment approaches to be explored. Further- 4. Bronson RT: Variation in age at death of dogs of different sexes and breeds,
Am J Vet Res 43:2057–2059, 1982.
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9. Companion animal trials are generally more economical to 2004.
perform than human trials. 7. Mukherjee S: The emperor of all maladies: a biography of cancer, New York,
10. Companion animals live long enough to determine the 2010, Scribner.
potential late effects of treatment. 8. LeBlanc AK, Breen M, Choyke P, et al.: Perspectives from man’s best friend:
11. Regional referral centers exist to concentrate case accrual and National Academy of Medicine’s Workshop on Comparative Oncology, Sci
Transl Med 8:324ps5, 2016.
facilitate clinical trials. 9. Linblad-Toh K, Wade CM, Mikkelsen TS, et al.: Genome sequence, compar-
12. Clients are often willing to allow a necropsy, which is a cru- ative analysis and haplotype structure of the domestic dog, Nature 438:803–
cial end point for not only tumor control but also treatment- 819, 2005.
related toxicity. 10. Mooney S: A snowflake in my hand, New York, 1989, Dell Publishing,
Bantam Doubleday.
13. Dogs and cats are large enough for high-resolution imaging
studies and multiple sampling opportunities, as well as for
surgical interventions.