Inanda Veterinary Hospital & Specialist Referrals, Waterfall, KwaZulu-Natal, South Africa
Caring for patients with cancer is about more than just chemotherapy. I understand that for many general practitioners, the prospect of embarking on chemotherapy (or radiotherapy or oncologic surgery) can be an intimidating prospect. Vets worry about broaching the subject of cancer and chemotherapy, which is emotive, with clients. We worry about whether or not the client will accept our advice to treat, and how much detail to go into with the pet owner. We worry about what will happen if there is a side effect, and the client's response to it (and our own response!). Some GPs will dismiss chemotherapy, because it doesn't cure patients and they end up euthanizing them anyway.
While all of these concerns are valid to a degree, my experience is that oncology is an immensely rewarding part of veterinary medicine. What makes my experience different? I think that at a fundamental level, my paradigm is different, and that is what this lecture will convey. Just as a surgeon approaches a complex fracture as a personal challenge and something rewarding, while another vet thinks about a colicky horse as a routine, rewarding oncology starts with a mindset. The wrong starting point is that cancer is invariably fatal. I have euthanized many dogs and cats because of crippling, unresponsive osteoarthritis, but I have cured many more dogs of cancer. If you're a dog, a diagnosis of dilative cardiomyopathy, osteoarthritis, diabetes mellitus, or Cushing's disease is a death sentence. The end may not be soon, but it will come about; there will be many tests, lots of medications (all with potentially disastrous side effects), sometimes pain or other forms of suffering. No dog was ever cured of DCM, or even arthritis; some pets are cured of cancer, and even those which cannot be cured, can be managed by medication and care. It's that care that we are discussing in this lecture. In my next lecture, I will talk more about laying the road for a pragmatic, caring and informed course of oncotherapy, whereas in this one I will restrict myself to talking about specific aspects of cancer care which, if you follow, will make the entire process more rewarding and successful.
Success in oncotherapy entails far more than just a percentage "remission rate" or "disease-free interval". Caring is far more than just curing a patient. Very often, I cannot cure a patient, but I can make them feel a lot better.
Loeb's Laws and Choosing your Endpoint, At the Start
Loeb's Laws are:
1. If what you're doing is doing good, keep doing it
2. If what you are doing is not doing good, stop doing it
3. If you don't know what to do, do nothing (get information or help!)
4. Never make the treatment worse than the disease
As oncologists, we sometimes violate rule (4), but only temporarily, and then we take great effort to prevent or ameliorate these effects. For example, rather than reacting to nausea and overt vomition, I dispense metoclopramide and the clients begin pre-treating patients on the morning of a scheduled chemotherapy, and then for another 3 days. An important part of this is explaining to clients that preventing nausea is an important facet of their care, and that it is more important (and cheaper!) than being able to control vomition once it has started.
Clients are usually very nervous and worried when they are first referred to the veterinary oncologist. They worry about the cost of treatment; whether they are doing the right thing in treating; pain; nausea; hair falling out; and if cure is possible.
Your first consultation with them is the most important one. Firstly, explain the process. I always start with a friendly and relaxed history-taking. I review any information the referring vet has provided (some will refer a patient after the minimum database, imaging and biopsies, others at the first sign of a mass). If the patient arrives with a thorough staging already done (TNM completed) I just review the history and physical examination for possible comorbidities and determine if there are any additional pieces of information I need to make decisions. Then, I ask the clients directly, what they are hoping we can achieve. Is it cure? Control? Relief from symptoms? From the outset, decide, based on your staging of the patient, and a frank discussion with the client, what is possible. Then let the client decide what they want to do, based on your advice. Let the client's decide! Clients can only make informed decisions when they have all the relevant information. Don't overload them with complexities of remission times and other jargon. Show that you care about results and their needs, not just problems to be ticked off a list. In most cases, I tell clients that, once the staging is complete, nothing they choose to do is wrong, except doing nothing. For a single mast cell tumour confined to a distal limb with clear staging, I would offer a client 1) radiotherapy (my choice); 2) amputation; 3) chemotherapy; whereas for an adrenal tumour with signs of hypercortisolism, I would offer 1) surgery (after a CT-angiogram), 2) chemotherapy with Lysodren or trilostane, or 3) euthanasia now or later.
I think it's important to offer euthanasia as an option of treatment, especially as a specialist, because some people may feel that they are "railroaded" into treatment by virtue of arriving at my doorstep. They aren't! Clients must feel that they make the important decisions about treatment, leaving the details to the vet.
I mentally place patients into one of the following categories:
1. Very highly curable - always stress curative-intent treatments over others, for the patient's interest (e.g., radiotherapy over imiquimod or cisplatin injection for nasal SCC in cats)
2. Highly curable - e.g., single MCT on the skin (radiotherapy or surgery)
3. Potentially curable but with a predilection for relapse or metastasis - try to cure, but initiate very diligent surveillance by vet and owner e.g., soft tissue sarcomas, bronchoalveolar carcinoma
4. Cure unlikely, but palliation in the long term possible with some modalities - e.g., multicentric lymphoma, oral melanoma
5. Cure unlikely, but medium-term palliation possible - e.g., splenic haemangiosarcoma, or a large PMNST (peripheral malignant nerve sheath tumour)
6. Incurable, but some palliation is possible - e.g., large brain tumours with seizuring, right atrial haemangiosarcoma with little tamponade
7. Incurable, requiring euthanasia - e.g., ruptured splenic haemangiosarcoma with metastases and collapse on presentation
Caring vs. Curing
It is possible to cure a patient but show very little care. This is not ideal and I would rather show care for all patients, than success but little heart. I think it's crazy to go through all the heroics of chemotherapy or radiation, and then ignore the patient's painful osteoarthritis, or periodontitis or fleas! Holistic medicine isn't homeopathy. Holistic medicine is caring for a patient's wellbeing - psychological, psychosocial, physiological - and a caretaker's experience of helping care. Clients are my "home care team"; their observations are important to me, but even more important is the quality and value, not just the quantity of time they have with their pet.
Pay particular attention to diet in cancer patients. No cancer patient should ever receive raw foods. Raw food + Chemotherapy = sepsis risk. Cooked foods are safer, their proteins and fibres already partially denatured and therefore easier to digest, and more "natural" for domestic animals. There is nothing "natural" about dogs and cats - they are domestic pets, genetically modified over millennia. Be aware of the consequences of food aversion, and avoid simple carbohydrates during the main portion of cancer. I find that one of the most important side effects of chemotherapy is weight gain and muscle loss from prednisolone. The use of exercise, especially hydrotherapy (or just a run on the beach!) is an important tool for offsetting this.
Patients who eat are generally less nauseous when given chemotherapy, so I normally advise a meal on the morning of chemo. I also advise clients against nutraceutical supplements and home-cooked diets, preferring Hill's Prescription Diet n/d or Eukanuba Working & Endurance as preferred diets. Keep it simple! If there is an episode of diarrhoea, I want to know that it isn't the diet! During episodes of diarrhoea, I find the use of withdrawal of food, use of glutamine-solutions e.g., Glutalyte, and gradual reintroduction with Eukanuba Intestinal or Hill's i/d to be very helpful. Patients who aren't eating or with intestinal disease will receive daily or weekly injections of Catosal (Bayer) as a rule, with blood cobalamin assays as an aid if necessary.
Psychology & Psychosocial Aspects
Dogs and cats, especially older animals, are very fixed in their habits and routines, and can become stressed or depressed when these are disrupted. I usually stress the importance of preserving routine. I think this also helps owners who have their own worries and must now give medications, bring pets in for weekly chemo or radiation, and so forth! Making the cat carrier a less intimidating place by leaving it (door removed) with the cat's normal bedding, sprinkled with catnip, near the food bowl, is helpful. You can also raise the cat carrier to make it a place of safety.
If your dog meets in the park with his friends, keep doing this! Just make sure all his friends are vaccinated and dewormed, and pay attention to this as well. In general, I will not vaccinate an animal with a lymphohaemopoietic neoplasia, except with the intranasal Bordetella bronchiseptica vaccine (Nobivac KC). This is despite the evidence that animals respond appropriately to vaccines, and is obviously in context of that patient. For example, in KwaZulu-Natal, South Africa, there is a high prevalence of rabies, and thus annual boosters are still given if there is a high likelihood of durable remission (just delay vaccination until after induction and consolidation).
One of the most undertreated consequences of human cancer. Its true role in veterinary patients is unknown. Patients hospitalised for long or repeated periods may certainly become depressed, and thus client visits, pleasant surroundings, mental stimulation, toys, and, where deemed necessary, Anxitane, pheromone-release collars or even tricyclic depressants may be deemed appropriate.
Lethargy & Fatigue
Lethargy (unwilling to initiate normal activity) and fatigue (rapid tiring once active) are important consequences of chemotherapy and cancer cachexia. Anthracycline-induced cardiotoxicity, cortisone-induced myopathy, Vinca neuropathy, and other organ-specific toxicities are important considerations that should be kept in mind, especially when a well-performing patient seems to deteriorate. A proper medical examination is required for these patients, and investigation where appropriate. I find an important part of patient monitoring is simple: weigh and body score every patient, at every visit, and record it. Get your receptionists and nurses to do this every time.
Teach your clients the signs of nausea (inappetence, lip-licking, depression, vomition) and to give metoclopramide aggressively. Hand feeding, novel feeding regimens, treats, and other tricks are necessary to keep pets eating. 48hrs of complete inappetence are one of my gatekeeper signs for euthanasia or intervention.
Diarrhoea is, in my experience, less frequent than nausea. Medications as well as prescription diets are necessary to manage them.
Patients with amputation in particular are very susceptible to staying down. A critical aspect is to screen patients for amputation before the procedure - check the other joints beforehand!
Most patients with cancer are older animals. It is imperative that these problems are assimilated into your treatment decisions, and managed aggressively, concurrent with the cancer.
Euthanasia and end-point planning; after-care
Dealing with owners
Dealing with disasters - owners and pets
Owner risks from chemotherapy and radiation
And will be dealt with in detail and giving examples, in the lecture.
Concentrate all your efforts towards helping patient live with cancer, not die from it. Cure when you can, heal and protect when you can't, and euthanize when you must. It's a difficult balancing act, but with compassion, common sense and a good knowledge of medicine will help. You must know the likely outcomes, and also the comorbidities. With all this information, you can help and guide clients and their pets through a cancer diagnosis.