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2016 AAHA Oncology Guidelines for Dogs and Cats

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Click to access information on the Management of Chemotherapeutic Extravasation

Abstract

All companion animal practices will be presented with oncology cases on a regular basis, making diagnosis and treatment of cancer an essential part of comprehensive primary care. Because each oncology case is medically unique, these guidelines recommend a patient-specific approach consisting of the following components: diagnosis, staging, therapeutic intervention, provisions for patient and personnel safety in handling chemotherapy agents, referral to an oncology specialty practice when appropriate, and a strong emphasis on client support. Determination of tumor type by histologic examination of a biopsy sample should be the basis for all subsequent steps in oncology case management. Diagnostic staging determines the extent of local disease and presence or absence of regional or distant metastasis. The choice of therapeutic modalities is based on tumor type, histologic grade, and stage, and may include surgery, radiation therapy, chemotherapy, immunotherapy, and adjunctive therapies, such as nutritional support and pain management. These guidelines discuss the strict safety precautions that should be observed in handling chemotherapy agents, which are now commonly used in veterinary oncology. Because cancer is often a disease of older pets, the time of life when the pet–owner relationship is usually strongest, a satisfying outcome for all parties involved is highly dependent on good communication between the entire healthcare team and the client, particularly when death or euthanasia of the patient is being considered. These guidelines include comprehensive tables of common canine and feline cancers as a resource for case management and a sample case history. (J Am Anim Hosp Assoc 2016; 52:181–204. DOI 10.5326/JAAHA-MS-6570)

Introduction

Every primary-care companion animal practice will encounter its share of oncology cases. This has never been truer since improvements in pet nutrition, widespread heartworm control, renewed emphasis on age-specific preventive pet healthcare, regular vaccinations, and senior pet screenings have led to a growing population of older dogs and cats. In fact, a large-scale (n > 74,000 dogs), two-decade demographic study of the Veterinary Medical Database found that neoplastic disease was the most common terminal pathological process in 73 of 82 canine breeds and the most common cause of death in dogs >1 yr of age, with an incidence >3 times that of traumatic injury.1 Because oncology cases are inevitable in clinical practice, some degree of expertise in diagnosis and treatment of cancer is expected by clients and is an essential component of a comprehensive primary-care veterinary practice.

The purpose of these guidelines is to provide practice teams with guidance for accurate diagnosis and optimal management of the canine and feline cancer patient. Because almost all pet owners have some acquaintance with cancer in their own lives, they will measure a veterinarian’s approach to managing an oncology case against their own experience. Perhaps to a greater degree than in other clinical situations, the client plays a prominent role in directing how a pet’s cancer is managed. For this reason, it is particularly important that veterinarians adopt an informed and systematic approach to managing an oncology case, including maintaining an active and empathetic dialogue with the owner in developing a treatment plan.

Every cancer case is different, even if the type of neoplasia is commonplace. For this reason, these guidelines are specific in many respects without being overly prescriptive. Within this framework, these guidelines offer the following sequential approach to managing each medically unique cancer case: diagnosis, staging, therapeutic considerations, careful attention to patient and personnel safety in handling chemotherapeutic agents, referral to an oncology specialty practice when appropriate, and a strong emphasis on client support.

Because oncology patients are frequently of an advanced age, their owners are often highly bonded to them and emotionally distraught after receiving a cancer diagnosis. Thus, a team approach emphasizing compassionate and transparent communication from clinical staff to pet owner and, in difficult cases, involving a referral center are critical factors in a satisfactory case outcome. A later section of these guidelines discusses in detail the importance of maintaining an empathetic, informed dialogue with the client, including techniques for discussing the patient’s prognosis and treatment options.

Because oncology cases have the potential to create a strong bond between the practice and the owner of a pet with cancer, primary-care veterinarians should be willing to consider treating select cases. The caveat in doing so is to ensure that the healthcare team is adequately trained and equipped to appropriately manage the case. A section on safety discusses in detail the safety precautions and equipment that are appropriate when chemotherapeutic agents are used. These include the equipment needed and methods used to protect the clinic environment as well as the healthcare team, the patient, and the pet owner.

Each type of cancer and organ system involved has a particular progression to be considered when staging the case and presenting treatment options to the pet owner. A critical aspect of successful oncology case outcome is to develop a treatment plan specific for the type of tumor involved. Readers will find the two comprehensive tables on common cancers of dogs and cats to be a concise and useful resource for this purpose. The task force wishes to emphasize that the information in the tables should not be interpreted as a “cookbook approach” to case management but rather a compilation of relevant, tumor-specific information to help guide decision making. A sample case history is also provided so that practitioners can consider how they would use the cancer tables to assess and treat the case.

These guidelines are not intended to be overly prescriptive, for example, they do not provide chemotherapeutic dosage recommendations. Other, more complete sources of information are available for such purposes. However, these guidelines do place special emphasis on three topics of paramount importance in oncology case management: safety in handling chemotherapeutic agents, delivery of radiation therapy, and relationships with the owners of cancer patients.

As in all aspects of clinical veterinary medicine, each member of the healthcare team represents the practice as a whole. An underlying theme of these guidelines is that all staff members, including clinical and administrative personnel, can positively influence the outcome of an oncology case. A unified healthcare team that speaks with one voice will actively support a long-term relationship with a client who entrusts the practice with the care of a pet diagnosed with cancer.

These guidelines were prepared by a task force of experts convened by the American Animal Hospital Association for the express purpose of producing this article. They were subjected to the same external review process as all JAAHA articles. This document is intended as a guideline only. Evidence-based support for specific recommendations has been cited whenever possible and appropriate. Other recommendations are based on practical clinical experience and a consensus of expert opinion. Further research is needed to document some of these recommendations. Because each case is
different, veterinarians must base their decisions and actions on the best available scientific evidence, in conjunction with their own expertise, knowledge, and experience.