Outline

• It IS the cancer!
• Tumor-related emergencies; Treatment-related emergencies
• It’s NOT the cancer!
• Concurrent diseases; Non-cancer-related emergencies
• Counseling oncology clients for emergency treatment

Why Should the Oncology Veterinary Nurse Learn About Oncology Emergencies?

Oncology patients may present on emergency, for reasons related to their cancer, cancer treatment, or completely unrelated to the cancer treatment. Understanding the reasons that oncology patients may present on emergency and how those emergencies are treated is vital to educating clients on what to watch for, and when to bring their pet in to be seen. The oncology veterinary nurse’s role in client education cannot be understated. Vet nurses have a connection with clients and are a great source of education for clients on what signs to watch for, what to do in case of severe treatment-related symptoms, when they should come in to the emergency service, and what they can expect if they come in for an emergency room visit.

Types of Oncology Emergencies

Emergencies can be tumor-related (such as a bleeding tumor, painful tumor, or pathologic fracture), due to paraneoplastic syndromes (such as a hypercalcemic patients with increased thirst and urination), or treatment-related (such as chemotherapy-induced febrile neutropenia or diarrhea, or radiation side effects). Non-cancer-related emergencies may be injuries (hit by car, bite wound), toxicities, or new/progressive comorbidities (progressive kidney disease in older cats, heart failure)—sometimes these concurrent diseases may be made worse by the treatment, or by the cancer.

Tumor-Related Emergencies

These are emergencies directly related to the cancer; patients may present to the emergency clinic with not-yet-diagnosed cancer, or known but newly progressive cancer. This includes patients that might present for acute onset of “lumps under the chin” (dogs with lymphoma) that may be bouncing around and feeling great, and patients with a bleeding splenic tumor that are acutely anemic and have severe hemoabdomen and need emergency surgery. The job of the emergency clinician is typically to stabilize the patient, control symptoms, treat pain, and sometimes achieve a diagnosis so that cancer therapy can get underway. In some cases, such as lymphoma, the emergency clinician or criticalist at a specialty hospital might start cancer therapy (for example, give a dose of L-asparaginase) if all diagnostic testing is done; however, in many cases, the pet will be stabilized to transfer to a specialist for treatment the next day.

Examples of types of tumor-related emergencies include:

• Hemorrhage—bleeding peripheral tumors; epistaxis; bleeding into a body cavity (hemoabdomen, hemopericardium, hemothorax); Yunnan Bai Yao is often advised
• Body cavity effusions—neoplastic effusions in the thorax or abdomen; some patients may require therapeutic tap
• Pain—ANY tumor can cause pain and all patients should be assessed for discomfort; if it’s ulcerated, bleeding, or bruised, it could be painful; NSAIDs, gabapentin, tramadol, Tylenol 3, fentanyl patch, etc.

Treatment-Related Emergencies

Cancer therapies used in pets include surgery, radiation therapy, chemotherapy, immunotherapy, and a variety of other forms of palliative medical therapy, including corticosteroids, bisphosphonates, and pain medications. Chemotherapy for pets is generally well-tolerated, and adverse effects, if they occur, are typically mild and self-limiting. It is important for the oncology nurse to know the typical side effects that occur and the timing of those effects, to be able to properly counsel and educate clients regarding symptom management.

• Radiation therapy effects include both acute and late toxicities; however, the most common reason for emergency presentation would be acute. Moist desquamation, mucositis, colitis, rhinitis, otitis, conjunctivitis/ blepharitis might be common reasons for presentation, and depend on the site being irradiated. These effects often start the second week of radiation and may get worse after the end of radiation, before they heal. Common treatments include pain control, antibiotics, anti-inflammatories, and sometimes topical therapy. An E-collar is imperative to prevent self-trauma.
• Chemotherapy side effects occur due to effects on rapidly dividing cell populations.
• The neutrophil nadir for most drugs is 7–10 days after chemotherapy, and typically neutrophil counts will rebound in about 36 hours. Patients that present with severe neutropenia (<1000) but normal body temperature are at high risk for infection and should receive oral antibiotics and discharged immediately. Patients that present with severe neutropenia and fever should be hospitalized for IV antibiotics and supportive care; these patients should also be worked up for a source of infection (e.g., pneumonia, skin infection, UTI). The prognosis is typically good for patients recognized early.
• The platelet nadir for most drugs is 7–14 days, counts often return to normal within 1–2 weeks. Platelet counts do not typically go low enough to cause clinical symptoms of bleeding.
• Immunotherapy or L-asparaginase could cause hypersensitivity reaction, such as hives, swelling, pruritus, or anaphylaxis.

Non-Cancer-Related Emergencies

It’s important to remember that oncology patients can always develop other non-cancer-related medical conditions. They can ingest foreign bodies, get bitten by snakes, undergo trauma, or experience HGE just like any other pet. Cancer is most common in older patients, and older patients often have comorbidities. Heart disease, chronic kidney disease, diabetes, Cushing’s, IBD, chronic GI diseases like pancreatitis, arthritis, seizures might all be conditions that oncology patients have been previously or currently managed for, or they might be newly diagnosed during cancer therapy. In some cases, the cancer or cancer therapy can cause comorbidities to worsen.

Client Education and Counseling

• Clients should be educated on how to check their pet’s rectal temperature if receiving a myelosuppressive drug and instructed to check the temperature if their pet is not feeling well. The most common drugs that could cause neutropenia include lomustine, mitoxantrone, carboplatin, cyclophosphamide, and doxorubicin. A fever in a patient that has had chemotherapy in the past 2 weeks (or past 3 weeks for carboplatin) should be considered a medical emergency.
• Pets should come in if: not acting like themselves, very lethargic, febrile, not eating or drinking for 12–24 hrs, diarrhea >3–6x over baseline, unable to take oral medications to treat symptoms, vomiting >3x or for >48 hrs, and/or not responding to medications. Err on the side of having them come in for evaluation!
• Pet owners should be informed about the general routine of a visit to the ER, as it may be different than they are used to. An estimate for treatment is usually provided, and pets are often triaged in the treatment area; however, the sickest and most urgent patients are treated first. The ER clinician will then examine the pet and provide consultation with the family on a recommended plan. Depending on whether the ER hospital is part of the same hospital system at which the pet is receiving cancer care, they may or may not have access to medical records, so clients should be instructed to bring medical records with them (often the most recent discharge instructions are best, as they will have an assessment and most recent therapy). In some cases, the emergency clinician will consult with the treating oncologist for help in managing the patient, but this is not always possible, or necessary. Preparing clients for emergency care is a key role of the veterinary oncology nurse, and can make the family more comfortable and the ER visit process go smoother.