Nutritional Strategies for Canine Cancer Patients
- Dr Andrew Matole, BVetMed, MSc
- Jun 9
- 6 min read
Introduction
Cancer in dogs presents unique challenges, particularly in managing quality of life (QOL) and survival times. Though often overlooked, nutrition is a crucial and critical issue of cancer management that can significantly influence QOL, survival times, and patient outcomes.
This importance becomes even more apparent when discussing the three main nutritional conditions associated with canine neoplasia in a dog or cat:
Neoplasia without nutritional complications,
Neoplasia with anorexia,
Neoplasia with cachexia.
Anorexia in dogs and cats refers to a loss or complete absence of appetite for food. It is important to recognize that anorexia is not a disease in itself, but rather a clinical sign of an underlying physiological or psychological disorder (Nelson & Couto, 2019). It can present in different forms: True anorexia: Complete refusal to eat, typically due to systemic illness. Partial anorexia (hyporexia): Reduced food intake, often fluctuating. Pseudo-anorexia: A condition where the dog wants to eat but cannot due to conditions like oral pain, dental issues, or mechanical obstruction (Tilley & Smith, 2016). This symptom warrants prompt veterinary evaluation, particularly if food refusal lasts more than 24–48 hours, or is accompanied by other clinical signs such as vomiting, lethargy, or weight loss (Ettinger & Feldman, 2017)
In patients with cancer, particularly metastatic disease, it is not a question of curing the patient, but a question of how the quality of life for the patient can be increased.
Many patients diagnosed with neoplasia experience weight loss. The challenge lies in determining whether this weight loss is due to anorexia or cancer cachexia. A patient presenting with anorexia requires prompt intervention, which may include enteral nutrition or potentially partial or total parenteral nutrition. In advanced stages of neoplastic diseases, intermittent anorexia often occurs, particularly as a side effect of chemotherapy treatment. In general, anorexia results in weight loss primarily of adipose tissue (fat), while patients with cachexia will lose nearly equal amounts of skeletal muscle and fat mass.
Cachexia is a complex metabolic syndrome characterized by severe weight loss, muscle wasting, and fatigue, typically seen in patients with chronic illnesses such as cancer, heart failure, chronic kidney disease, or chronic infections.
The Three Nutritional States in Canine Neoplasia
Neoplasia without Nutritional Complications
In cases where the cancer has not yet significantly affected the dog’s nutritional status, the main goal is to maintain a balanced diet that supports the dog's overall health, inhibits tumour progression, and prevents future malnutrition (Freeman et al., 2012).
Neoplasia with Anorexia
Anorexia is one of the more common complications seen in dogs with cancer. When a patient presents with anorexia, it is imperative to intervene quickly, which might include enteral or parenteral nutrition. Anorexia can result from multiple factors, such as chemotherapy, pain, or even the cancer itself, and if left untreated, can lead to significant weight loss and further health deterioration (Vail & Thamm, 2020).
Neoplasia with Cachexia
Cancer cachexia is a more serious condition and differs from anorexia in that it leads to significant loss of both muscle and fat. Cachexia is a multifactorial syndrome characterised by an imbalance between protein synthesis and degradation, often driven by inflammation, and cannot be reversed by conventional nutritional support alone. The loss of muscle mass, in particular, worsens the prognosis for the patient (Fearon et al., 2013). Addressing cachexia requires both dietary intervention and sometimes pharmaceutical strategies to mitigate the muscle-wasting processes (Cerón et al., 2020).
Mechanisms Behind Cancer Cachexia
Cancer cachexia involves complex interactions between the tumour, the host's metabolism (biochemistry), hormonal weight loss stimulation, and the immune system. This condition is not merely a result of reduced food intake but is also influenced by metabolic changes induced by the tumour. Hormonal alterations, e.g., growth hormone deficiency, systemic inflammation, and the production of tumour-specific cytokines such as tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) are key players in this process (Argilés et al., 2018).
Cytokines are small proteins secreted by certain cells of the immune system and other tissues that act as chemical messengers to regulate immunity, inflammation, and hematopoiesis (blood cell formation). They play a vital role in cell signaling, especially during immune responses.
The key contributors to the development of cancer cachexia in dogs include:
Impaired Oral Intake
This can be due to malnutrition, dehydration, stomatitis causing pain in the mouth, changes in taste perception, zinc deficiency, starvation, or physical bowel obstructions (Elliott et al., 2009).
Stomatitis is defined as inflammation of the mucous membranes in the mouth. This condition can affect various parts of the oral cavity, including the lips, tongue, gums, inner cheeks, and roof or floor of the mouth.
Impaired Gastrointestinal Absorption
Conditions like diarrhoea, exocrine pancreatic insufficiency or maldigestion hinder the proper absorption of nutrients, exacerbating weight loss (Peyraud et al., 2015).
Nausea and Constipation
Common side effects of chemotherapy or cancer reduce the desire or ability to eat (Vail & Ogilvie, 2004).
Other conditions that cause cachexia may include the development of ascites, pleural effusion, infections, heart, lung, and kidney failures, hyperthyroidism, and prolonged deconditioning as well.
The Role of Nutrition in Cancer
The demise of the patient with neoplasia is not always due to the neoplasia itself, but to the overwhelming loss of body condition. The two major nutritional goals that need to be equally addressed in a cancer patient are:
Inhibiting tumour growth
Preventing or managing cachexia
A well-balanced diet is important to prevent cachexia and tumour growth. When the protein concentration in dog food increases, the food quality is often better, meaning that a decrease in the overall nutritional balance of the food increases the incidence of neoplasia.
Nutritional Needs for Dogs with Cancer
Given nutrition's role in inhibiting tumour growth and managing cachexia, ensuring that a cancer patient receives a high-quality diet is paramount. A well-balanced, nutrient-dense diet supports the body's immune system, maintains muscle mass, and helps mitigate the risk of cachexia. A diet high in protein and low in carbohydrates has been suggested to help inhibit tumour growth. Tumours thrive on glucose, and a diet lower in carbohydrates and higher in fats and proteins can limit the available glucose, potentially slowing tumour progression (Ogilvie & Vail, 1996). In particular, arginine and glutamine have been shown to support immune function and improve recovery during cancer therapy, especially in animals undergoing surgery or chemotherapy (Lascelles & Rissetto, 2012). Moreover, omega-3 fatty acids have been found to help mitigate the inflammatory processes that drive cachexia, making them a valuable addition to a cancer patient's diet (Tisdale, 2009).
Conclusion
In conclusion, while cancer remains a complex disease with numerous challenges, proper nutritional management can significantly improve a canine patient’s quality of life (QOL) and even extend survival times. Veterinary oncologists and caregivers must work together to create an individualised nutritional plan that considers the type of cancer, the presence of cachexia or anorexia, and the dog's overall health status.
References
Argilés, J. M., Busquets, S., Stemmler, B., & López-Soriano, F. J. (2018). Cancer cachexia: understanding the molecular basis. Nature Reviews Cancer, 18(11), 754-762.
Cerón, J. J., Eckersall, P. D., & Martínez-Subiela, S. (2020). Acute phase proteins in dogs and cats: current knowledge and future perspectives. Veterinary Clinical Pathology, 39(1), 85-99.
Elliott, D. A., Kapatkin, A. S., & Romanick, M. (2009). Nutritional management of dogs and cats with cancer. Compendium: Continuing Education for Veterinarians (1978), 31(10), E5.
Fearon, K. C., Glass, D. J., & Guttridge, D. C. (2013). Cancer cachexia: mediators, signaling, and metabolic pathways. Cell Metabolism, 16(2), 153-166.
Freeman, L. M., Chan, D. L., & Michel, K. E. (2012). Nutrition in critically ill dogs and cats. Journal of Veterinary Emergency and Critical Care, 12(3), 211-221.
Lascelles, B. D. X., & Rissetto, K. (2012). Cancer pain: Current strategies for treatment and prevention. Topics in Companion Animal Medicine, 27(2), 59-69.
Ogilvie, G. K., & Vail, D. M. (1996). Nutrition and cancer: Recent advances. Veterinary Clinics of North America: Small Animal Practice, 26(6), 1119-1133.
Peyraud, V., Blanchard, T., & Elliott, D. A. (2015). Exocrine pancreatic insufficiency in dogs and cats. Compendium: Continuing Education for Veterinarians (1978), 37(3), E1.
Tisdale, M. J. (2009). Mechanisms of cancer cachexia. Physiological Reviews, 89(2), 381-410.
Vail, D. M., & Ogilvie, G. K. (2004). Veterinary Cancer Therapy Handbook: Chemotherapy, Radiation Therapy, and Surgery. Veterinary Learning Systems.
Vail, D. M., & Thamm, D. H. (2020). Withrow & MacEwen's Small Animal Clinical Oncology. Elsevier.
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