Definitions and scope
The sources separate palliative care from hospice care. In the AAFP/IAAHPC guidelines, hospice applies once a life-limiting illness is diagnosed and medical goals move away from curing the condition toward comfort and quality of life. Palliative care covers both curable and incurable disease [2]. Paz and colleagues describe hospice as a narrower group within palliative care, reserved for patients near the end of life [1]. They also split palliative care into early care, delivered to outpatients or hospitalized patients, and late care, delivered in hospices, palliative units, or at home [1].
One difference between sources matters for readers. The Veterinarni Medicina review frames palliative care around patients for whom no chance of a cure remains [3]. Paz and colleagues instead point to human oncology evidence favoring palliative care soon after diagnosis [1]. They note that in veterinary practice palliative care is often considered only once anticancer therapy stops [1].
None of the cited sources offer a staging system for palliative patients. The closest framework is the illness trajectory model in the feline guidelines. It describes four patterns, and the guidelines say cancer often follows the type 1 pattern, "a short period of decline close to death, which may evolve over days or weeks" [2].
Who needs it and how cancer patients present
The Veterinarni Medicina review cites estimates that neoplasms cause about half of deaths in dogs over 10 years old and that roughly one in four dogs will develop cancer [3]. Paz and colleagues describe cancer as the leading cause of illness and death in elderly dogs and cats [1].
According to the Veterinarni Medicina review, pain in pets with cancer is likely underestimated. The review cites a survey in which 87% of veterinarians agreed that cancer pain is underdiagnosed and 66% disagreed that it is easily treated [3]. The review lists possible sources of pain, including direct tissue invasion, organ distension or obstruction, nerve compression, and chemotherapy sequelae [3]. It also lists behavior changes owners may notice, such as altered posture, reduced self-care, poor appetite, focal licking, and changes in urination or defecation [3].
Cachexia is a syndrome of muscle and fat wasting with progressive weight loss. The same review cites an incidence of around 25% in dogs with various neoplasms [3]. Paz and colleagues note that comorbidities such as osteoarticular and endocrine disease are common in older cancer patients [1]. They also report that patients with advanced or metastatic disease can receive treatment in emergency services without invasive tests for a definitive diagnosis [1].
Quality-of-life assessment
Several tools appear in the sources. They differ in how well they have been tested.
| Tool | What the source says | Validation status per sources |
|---|
| HHHHHMM scale | Pain, hunger, hydration, hygiene, happiness, mobility, more good days than bad, each scored 0 to 10; 35 or more suggests acceptable QOL [3] | Listed among non-validated tools [2] |
| Canine Symptom Assessment Scale (CSAS) | Developed at the University of Pennsylvania in dogs with solid tumors; 12 predefined symptoms plus two additional, covering the past 10 days [1] | Not stated |
| Cancer Treatment Form | 23 multiple-choice questions on happiness, pain, appetite, hygiene, mental status, hydration, mobility, and overall health in dogs and cats [1] | Described as validated by the review [1] |
| 20-item feline HRQOL instrument | Owner-completed online; domains of vitality, comfort, and emotional wellbeing; development included cats with painful and non-painful cancer; fee based [2] | Validated generic instrument [2] |
| Journeys Home calculator, Ohio State QOL assessment | Owner tracking tools [2] | Not validated [2] |
The feline guidelines say that a tool not being validated does not mean it should not be used, because the main goal is to engage caregivers in tracking their cat over time [2]. The guidelines name two purposes for these instruments: monitoring treatment effects and supporting euthanasia decisions [2].
Giuffrida and Kerrigan's 2014 systematic review in the Journal of Veterinary Internal Medicine examined 144 prospective studies of cancer treatment in client-owned dogs and cats published from 2008 to 2013 [4]. Sixteen studies measured quality of life and eight reported the results. Only one gave enough detail for the measurement to be replicated [4]. Among studies that referenced or provided a complete QOL instrument, a modified Karnofsky performance status scale was the most commonly used. The authors note that its ability to measure function or quality of life in pets is unknown [4]. Studies from 2011 to 2013 were significantly more likely to measure quality of life than earlier ones [4]. The authors acknowledge some limitations. Relevant articles were necessarily missed because of language ineligibility, database limitations, or investigator oversight, and a single investigator assessed each article, which could introduce misclassification [4].
The same authors note that QOL scales in the veterinary literature are mainly suggested as means to facilitate discussions about euthanasia and palliative treatment goals. They add that unvalidated instruments could be adequate in that setting, because the goal is not truly to measure or compare QOL [4].
Delivering care
The feline guidelines set out five steps, and Paz and colleagues describe the same protocol, attributing it to Shearer [1][2]:
- Evaluate the caregiver's needs, beliefs, and goals for the animal.
- Educate the caregiver about the disease process and how care will be delivered.
- Develop a personalized plan for the animal and caregiver.
- Apply hospice or palliative techniques, with written instructions and demonstration.
- Provide emotional support during care and after death.
The guidelines frame step 1 around "personal budgets," meaning the financial, emotional, physical, and time resources a caregiver has available [2]. In step 3, the plan includes an assessment of the caregiver's capability and willingness, an assessment of the patient's willingness and capacity to receive care, a detailed written plan, time and cost estimates, and a follow-up schedule [2].
Both sources describe care delivered by a team. The feline guidelines extend the "unit of care" to include caregivers. They state that veterinary teams alone are not trained to meet people's psychological, social, and spiritual needs [2]. Paz and colleagues list several possible team members: veterinarians, technicians, social workers, volunteers, chaplains, and grief counselors. They note that psychological support for owners and staff is not often offered [1].
Symptom management approaches
The Veterinarni Medicina review describes the WHO three-step analgesic ladder as extrapolated to dogs and cats. NSAIDs are used for mild pain, codeine or tramadol is added for moderate pain, and stronger opioids are used if pain remains uncontrolled. Gabapentin and amitriptyline are options as adjuncts for chronic pain [3]. The same review notes evidence that tramadol does not give adequate analgesia for chronic pain in dogs. It also reports that one author advises against stopping gabapentin abruptly because of seizure risk [3]. The review says patients with round cell tumors such as lymphoma, mastocytoma, and histiocytic sarcoma may benefit from corticosteroids [3]. Paz and colleagues specify that paracetamol is for dogs only and should not be given to cats [1].
Metronomic chemotherapy means low, continuous, usually oral doses of cytotoxic drugs. The Veterinarni Medicina review lists its main indications as palliative control of recurrent, inoperable, or metastatic tumors. It also covers patients who are extremely debilitated or whose owners reject conventional therapies because of the risk of adverse effects [3].
Paz and colleagues state that force-feeding "should not be recommended" [1]. The feline guidelines warn that forced feeding can worsen food aversion, nausea, pain, and distress [2]. The guidelines also cite a study putting medication compliance in cats at 76% because of the stress involved. They describe feeding tubes as a way to give medications, nutrition, and fluids that may reduce stress [2].
Ethics and end-of-life decisions
The feline guidelines and the Veterinarni Medicina review both apply four bioethical principles: respect for autonomy, non-maleficence, beneficence, and justice [2][3]. The feline guidelines extend autonomy to the cat's willingness to take part in its own care. They state that forcing medications or painful wound care on a fearful cat violates that autonomy [2]. According to the guidelines, when ongoing pain cannot be palliated, non-maleficence and beneficence "must drive a discussion about humane euthanasia" [2].
The Veterinarni Medicina review notes that cancer patients rarely die of their disease, because euthanasia usually comes first [3]. Paz and colleagues cite an interview-based study on palliated natural death under sedation. In that study, 5% of veterinarians approved without conditions and 61% approved conditionally, provided pain could be controlled and owners could provide care [1]. The feline guidelines note that veterinary professionals are beginning to use the terms "hospice-assisted death" or "palliated death." They say the earlier term "natural death" can carry connotations that may affect decisions [2].
