Common Cancers, Common Cures©

Common Cancers, Common Cures

Many people are surprised to learn that animals are faced with many of the same diseases as people. Dogs and cats can get cancer? If they get cancer it can be treated?

In fact, cancer is unfortunately quite common in companion animals, with some figures indicating that it is the leading cause of disease-related death in 47% of dogs and 32% of cats (Animal Health Survey, Morris Animal Foundation, 1998). Furthermore, the disease kills nearly 50% of dogs over the age ten (What You Should Know About Cancer in Animals, American Veterinary Medical Association, 2004).

With cancer being so prevalent in companion animals and with the advancement of the treatment of this disease in animals, a better understanding of cancer in general is being obtained through veterinary studies. The study of cancer in our best friends is already leading to additional treatment options for people too.

By supporting programs such as the ACVIM Foundation Grant Program, you may not only help your four-legged friend, but you could very well be helping your husband, daughter, mother or neighbor.

Below is a brief article by Dr. Philip Bergman and Dr. Jeffrey Toll that explains this topic in further detail and discusses pioneering work in the treatment of bone cancer and melanoma. Please help us in finding common cures for these common cancers.

The study of cancer in pet animals enhances
our understanding of cancers in people.

Prepared June 2007 by Philip J. Bergman, DVM, MS, PhD, DACVIM(Oncology) and Jeffrey Toll, VMD, DACVIM.*

The field of veterinary oncology is a relatively young one. The recognized specialty of oncology within the American College of Veterinary Internal Medicine (ACVIM) is just over 20 years old. There are approximately 170 ACVIM board-certified veterinary oncologists, about as many as can be found in a single major human cancer center. ACVIM diplomates in oncology (i.e. oncology specialists) primarily work in veterinary schools and teaching hospitals and at private specialized veterinary referral practices in major metropolitan areas. While the primary activity of a veterinary oncologist is the care of animals afflicted with cancer, many devote significant amounts of time performing research to improve the diagnosis and treatment of animals as well as people with cancer.
Although investigators in human oncology have relied on murine (mouse) models to perform their research for many years, serious limitations on the use of these models have been identified. (1-3) It is now understood that artificially induced cancers in murine models do not bear enough similarity to spontaneous human tumors to be accurate or useful for research in many instances. However, the spontaneous cancers of pets treated by veterinary oncologists are quite similar to those arising in people. If one looks at specific types of cancer, the canine and/or feline form is often quite similar to the human form on a variety of levels including anatomic location, age of occurrence, sites of metastasis, as well as response or resistance to certain types of therapy. Therefore, numerous investigators believe that the study of veterinary oncology patients may better predict or reflect human cancers.(4-7)

Based on these similarities across species, veterinary cancer research benefits both animals and humans with cancer. Some of the most enlightened, credentialed, and sophisticated veterinary and human cancer specialists work collaboratively for the benefit of animals and people. Although still limited in scope, this collaboration is a natural progression in the evolution of biomedical research and it is the realization of the One Medicine concept whereby all biomedical research is applicable to some extent in many species. In the case of oncology, the use of investigational diagnostic tools and/or treatments in animals, if successful, paves the way for use in human oncology patients. One of the earliest studies with significant impact on human cancer was the study of dogs with osteosarcoma (a common type of bone tumor) utilizing a limb sparing surgical procedure by Withrow and colleagues at the Colorado State University School of Veterinary Medicine.(8,9) Prior to the development of this technique, limb amputation was the only treatment option, so a surgical technique allowing for tumor removal without amputation (i.e. limb-sparing) was a very significant step forward. As this technique was perfected in dogs, it was adopted by human oncologists for use in children with osteosarcoma, preventing many limb amputations and re-inventing the standard of care for people.(10)

London and colleagues have performed studies in dogs utilizing a new class of sophisticated anti-tumor agents that target tumor cells through tyrosine kinase inhibition (TKI), a technique that spares healthy tissues and thus avoids common chemotherapeutic side-effects.(11) Her studies showed that dogs with various tumors responded to these agents, and that the response was targeted and specific. (12) This has led the way for human investigators to try various TKI’s on a variety of human malignancies.(13)

Dogs with malignant melanoma have extremely similar tumors to people with advanced melanoma.(14) In a unique collaboration between veterinary cancer investigators, human cancer investigators and an industrial partner, a canine melanoma vaccine was tested and recently approved by the USDA while studies were just beginning in humans.(15) This represents the first US-government-based approval of a vaccine for the treatment of cancer and also shows how veterinary and human cancer centers can work together to benefit animals and people.

A multitude of other types of cancer are remarkably similar between dogs and/or cats and humans. In addition to the aforementioned osteosarcoma and melanoma, other tumors with similarities across species includes lymphoma, soft tissue sarcoma, head and neck tumors and a variety of others.(7) It is already known that mouse models of human cancer are not very predictive of outcomes in human cancer, and more predictive models utilizing pets with cancer are available. Regardless, conservative estimates of annual federal and corporate funding for research based on murine models of cancer are measured in the hundreds of millions of dollars, more than the federal allotment for the entire veterinary profession. The role of the ACVIM veterinary oncologist in the evolution of clinical oncology, both veterinary and human, is inestimable, poorly understood, and grossly underfunded.

Reference List

(1) Sharpless NE, Depinho RA. The mighty mouse: genetically engineered mouse models in cancer drug development. Nat Rev Drug Discov 2006 September;5(9):741-54.
(2) Pegram M, Ngo D. Application and potential limitations of animal models utilized in the development of trastuzumab (Herceptin): a case study. Adv Drug Deliv Rev 2006 August 7;58(5-6):723-34.
(3) Schuh JC. Trials, tribulations, and trends in tumor modeling in mice. Toxicol Pathol 2004 March;32 Suppl 1:53-66.
(4) Kimmelman J, Nalbantoglu J. Faithful companions: a proposal for neurooncology trials in pet dogs. Cancer Res 2007 May 15;67(10):4541-4.
(5) Vail DM, MacEwen EG. Spontaneously occurring tumors of companion animals as models for human cancer. Cancer Invest 2000;18(8):781-92.
(6) MacEwen EG. Spontaneous tumors in dogs and cats: models for the study of cancer biology and treatment. Cancer Metastasis Rev 1990 September;9(2):125-36.
(7) Khanna C, Lindblad-Toh K, Vail D, London C, Bergman P, Barber L, Breen M, Kitchell B, McNeil E, Modiano JF, Niemi S, Comstock KE, Ostrander E, Westmoreland S, Withrow S. The dog as a cancer model. Nat Biotechnol 2006 September;24(9):1065-6.
(8) LaRue SM, Withrow SJ, Powers BE, Wrigley RH, Gillette EL, Schwarz PD, Straw RC, Richter SL. Limb-sparing treatment for osteosarcoma in dogs. J Am Vet Med Assoc 1989 December 15;195(12):1734-44.
(9) Withrow SJ, Liptak JM, Straw RC, Dernell WS, Jameson VJ, Powers BE, Johnson JL, Brekke JH, Douple EB. Biodegradable cisplatin polymer in limb-sparing surgery for canine osteosarcoma. Ann Surg Oncol 2004 July;11(7):705-13.
(10) Varan A, Yazici N, Aksoy C, Gedikoglu G, Yalcin B, Akyuz C, Kutluk T, Buyukpamukcu M. Treatment results of pediatric osteosarcoma: twenty-year experience. J Pediatr Orthop 2007 March;27(2):241-6.
(11) London CA, Hannah AL, Zadovoskaya R, Chien MB, Kollias-Baker C, Rosenberg M, Downing S, Post G, Boucher J, Shenoy N, Mendel DB, McMahon G, Cherrington JM. Phase I dose-escalating study of SU11654, a small molecule receptor tyrosine kinase inhibitor, in dogs with spontaneous malignancies. Clin Cancer Res 2003 July;9(7):2755-68.
(12) Pryer NK, Lee LB, Zadovaskaya R, Yu X, Sukbuntherng J, Cherrington JM, London CA. Proof of target for SU11654: inhibition of KIT phosphorylation in canine mast cell tumors. Clin Cancer Res 2003 November 15;9(15):5729-34.
(13) Oehler V, Radich JP. Monitoring patients with chronic myeloid leukemia receiving Abl tyrosine kinase inhibitor therapy. Clin Lymphoma Myeloma 2007 March;7 Suppl 2:S58-S63.
(14) Bergman PJ, McKnight J, Novosad A, Charney S, Farrelly J, Craft D, Wulderk M, Jeffers Y, Sadelain M, Hohenhaus AE, Segal N, Gregor P, Engelhorn M, Riviere I, Houghton AN, Wolchok JD. Long-term survival of dogs with advanced malignant melanoma after DNA vaccination with xenogeneic human tyrosinase: a phase I trial. Clin Cancer Res 2003 April;9(4):1284-90.
(15) Bergman PJ, Camps-Palau MA, McKnight JA, Leibman NF, Craft DM, Leung C, Liao J, Riviere I, Sadelain M, Hohenhaus AE, Gregor P, Houghton AN, Perales MA, Wolchok JD. Development of a xenogeneic DNA vaccine program for canine malignant melanoma at the Animal Medical Center. Vaccine 2006 May 22;24(21):4582-5.

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