Cancer is a boogeyman in the world of health. It’s common, it’s usually incurable, it’s devastating, and it can happen to just about anyone or anything. It’s no wonder pet owners face a crisis when their beloved dogs are diagnosed with something like Canine Lymphoma.
As vets, it’s our responsibility to help convey the realities of the situation with care and tenderness while also providing the best possible options and outcomes for pet owners from all walks of life. That means knowing all we can about the disease, the possible treatment options, and the repercussions of prescribing specific options.
Over 8 million cats and dogs are diagnosed with cancer every year, but less than one in ten of them ever see an oncologist for their treatment. Of course, most vets don’t have oncology training. Much like with human healthcare, primary care professionals provide filtering and first-line treatment for various issues and consult with specialists when a diagnosis needs expertise they don’t have.
Advancements in veterinary science, new cancer treatments, and more specialized knowledge are at your fingertips. Canine cancers like lymphoma and their treatments are one such specialty. Veterinarians may not be trained in handling these cases, but we are and can help. Whether you need written guidance, a direct consultation, or general recommendations, please let us know, and we’ll find a way to help.
Canine lymphoma is often treated with Prednisone, but is that the best choice? Read on to find out more.
What is Canine Lymphoma?
Take it straight from the source:
“Canine lymphoma is a disease arising from the uncontrolled and pathologic clonal expansion of lymphoid cells of either B- or T-cell immunophenotype. Canine lymphoma most commonly involves organized primary and secondary lymphoid tissues, including the bone marrow, thymus, lymph nodes, and spleen. In addition to these lymphoid-rich organs, extranodal sites affected by lymphoma include the skin, intestinal tract, liver, eye, CNS, and bone. Lymphoma is reported to be the most common hematopoietic neoplasm in dogs, with an incidence reported to approach 0.1% in susceptible dogs.” – Merck Manual.
As one of the most common forms of cancer a dog can experience, lymphoma will be part of any vet’s patient roster sooner or later. Knowing how to treat it is extremely important.
Lymphoma in dogs comes in a number of different forms, but all of them generally respond well to initial treatments, and the dog is likely to go into remission, at least temporarily.
However, the vast majority of dogs with lymphoma will eventually relapse, meaning that treatments are palliative, aimed at extending quality of life rather than curing the underlying disease.
The most common course of treatment for canine lymphoma is a protocol involving a handful of chemotherapy drugs and Prednisone.
How Does Prednisone Help Canine Lymphoma?
As a corticosteroid, Prednisone (and prednisolone, a similar drug) have wide-ranging effects on the body. Prednisone is commonly used for a variety of purposes, including as an anti-inflammatory and as an immunosuppressant.
It’s this latter effect that comes into play with lymphoma. This is because the biological mechanisms that lymphoma uses to propagate itself are nearly identical to the mechanisms the immune system uses to flare up.
A high dose of Prednisone suppresses this mechanism and not only suppresses the spread of lymphoma; it can actually kill some of the cancerous cells.
While this sounds promising, there are a few caveats.
The first is that this suppressant effect is temporary at best and is never total. Prednisone can slow the spread of lymphoma and extend the life of a dog with the disease, but it does not cure the underlying disease; it always comes back, and often sooner rather than later.
Prednisone may alleviate some cancer symptoms, giving the appearance of improvement but not addressing the underlying disease; this could potentially delay more effective treatments.
The third is something we’ll get into soon; Prednisone is potentially bad as a cancer treatment in certain situations.
Iowa State University performed a study called CALYPSO, the Canine Lymphoma Steroid Only trial, to evaluate the outcomes of steroid-only treatment for canine lymphoma and to look for differences between response rates and quality of life across different forms of the disease.
They found roughly the same improvement across all dogs regardless of staging and type of the disease.
The Pros and Cons of Prednisone for Canine Lymphoma
Prednisone should generally not be considered the first-line treatment for canine lymphoma, but it may be - depending on the patient’s situation. There are a few distinct pros and cons of using pred as your treatment.
Pro: Prednisone is among the least expensive treatment options.
Pred is in the golden zone for medical treatments. It’s easy to manufacture and is used in treatment plans for a wide range of different ailments, from advanced diseases like cancer to simple skin rashes, and for dealing with the inflammation caused by other problems. That means it’s very inexpensive, easy to obtain, and well within reach of most pet owners.
It’s often considered the go-to treatment for pet owners who want to do something but don’t have the funds to handle expensive radiation and chemotherapy treatments.
Though variations in the availability of medications, charges from vets, and changes in pricing can always impact the total cost, prednisone doses are generally only a few cents each, while individual doses of a chemotherapy regimen can be $150-$600.
The difference is stark.
Pro: Prednisone is easy to administer to most dogs.
One of the benefits of pred is that it’s not hazardous to handle, and it’s easy to administer. One of the more common forms of Prednisone for dogs is a small white pill, which can be easily stuck into a treat and given to a dog to chow down and enjoy. They can also be made into a flavored chewable treat.
Other kinds of treatments, particularly chemotherapy, have many more safety warnings and requirements for the handling and storage of the medications due to their strength and intensity. Some can only be given in a vet or veterinary oncologist’s office.
Pro: Prednisone treatment can extend the expected survival time of a patient by 2-3 months.
While a few months might not seem like much, the expected lifespan of a typical dog diagnosed with canine lymphoma is only about a month.
Doubling or tripling the expected survival time for a patient is not a terrible outcome, and for pet owners on a budget, it’s better than nothing.
Con: Prednisone is among the least long-term effective treatment options.
While pred is effective in 50% of dogs with canine lymphoma, other treatment options like the CHOP protocol have much better outcomes. The multi-drug chemotherapy protocol attacks cancer cells from several different angles at once, working cooperatively to push back the disease and, in many cases, lead to remission for 9-12 months, with some dogs responding even better for longer survival outcomes.
Outcomes, of course, vary according to a wide range of factors, including genetic predisposition, drug reactions, the type and location of the lymphoma, and more.
Con: Prednisone can have numerous side effects.
Because pred is a corticosteroid, it affects the whole of the body across a number of different bodily systems. While its immunosuppressant effects help it destroy cancer cells, it is also causing numerous side effects.
These can include:
Increased thirst.
Increased urination.
Increased appetite.
Changes in bowel movements.
A pot-bellied appearance.
Lethargy.
While these are generally mild and can be managed for the short-term duration of a course of Prednisone, they aren’t the only possible side effects. In rare cases, dogs taking large doses of Prednisone might encounter the following:
Allergic reactions, which can be severe.
Changes in behavior, including increased aggression.
Loss of strength and mass in the muscles.
Prednisone has other side effects as well, like an increased risk of diabetes or Cushing’s disease, but these aren’t generally meaningful when you’re measuring the remaining life span of a dog in months. Perhaps the biggest risk beyond the above is the immunosuppressant effect itself.
Suppressing the immune system makes a patient more susceptible to infections, which can themselves be dangerous.
Lastly, Prednisone should not be stopped abruptly, as it may cause withdrawal symptoms or a relapse of the condition in the patient. The dosage must be gradually tapered to avoid complications.
Con: Prednisone can interfere with other treatments for lymphoma.
Prednisone may interact with other medications your dog is taking, potentially leading to adverse effects or reduced efficacy of the medicines.
This is the largest risk of using Prednisone as a treatment for lymphoma, and we’ve dedicated the entire next section to it.
Why Prednisone Isn’t Always a Good Option
While Prednisone can kill some cancer cells, many of them will still survive. Those that do survive tend to become more resistant to chemotherapy drugs, making their cancer drug-resistant.
This means that chemotherapy ceases to be an effective treatment for canine lymphoma.
“If Prednisone is given prior to starting chemotherapy treatment, it can actually induce drug resistance (by “upregulating” a tiny pump on the cancer cell membrane that pumps anti-cancer drugs out of the cancer cell, helping them be resistant), making the disease immune resistant to the chemotherapy itself. The resistance to Prednisone can be transferred to many chemotherapy drugs, thereby blocking the effectiveness of the subsequent chemotherapy treatment.
Prednisone is the classic example of drug resistance and can induce drug resistance, so if a patient was on Prednisone, but then the drug stops working for the disease, at that point chemotherapy will probably no longer be a useful option because the Prednisone will likely have caused the disease to be resistant to all other known conventional Canine Lymphoma treatments. And in those cases, once the Prednisone fails, there may be nothing more your vet can do to help your dog going forward.” – Dr. Kim Freeman.
Pred is moderately effective and very inexpensive for short-term gains while reducing the potential effects of long-term treatments. The alternative, in a CHOP protocol, is dramatically more expensive and more difficult to administer but correspondingly more effective.
In an ideal world, patient finances wouldn’t be an issue, and we could all do what we can to provide the most successful outcomes possible. Unfortunately, we don’t live in that world.
Does That Mean Prednisone Should Be Avoided?
Absolutely not!
Prednisone is an effective treatment for a wide range of conditions, but even for canine lymphoma, it’s still viable for situations where short-term palliative care is desired, where a patient has demonstrated less tolerance for or response to chemotherapy drugs, and of course in cases where finances restrict available treatment options.
“Despite these problems and complications caused by Prednisone treatments alone, Prednisone used in conjunction with certain chemotherapy protocols (for example, as part of the Madison Wisconsin Protocol) has been found to make those treatments more effective. So while, for most cases, caretakers should generally avoid Prednisone as a solo treatment for anything but short-term Canine Lymphoma care, don’t be surprised if your vet incorporates Prednisone into part of a more expansive Canine Lymphoma treatment.” – Dr. Kim Freeman.
Prednisone can be part of a comprehensive treatment option, or it can be a short-term benefit to patients that otherwise cannot take a stronger treatment.
The Second Opinion
Most local vet clinics don’t have a trained oncologist on staff. Not only does this limit potential treatment options and customized care, but it also can limit how effectively the vet can administer complex treatments like the chemotherapy and radiation involved in detailed, canine lymphoma treatments.
Fortunately, there’s another option available. Our service provides detailed consultation reports, which include diagnosis, pathology as relevant, interpretation of the results and bloodwork, typical behavior that can be expected as well as the usual prognosis, prognosis with various treatment options as well as an evaluation of those treatment options, and much more.
It’s not feasible for every vet to have an oncologist on staff. With our service, though, you can have one on call. It’s a simple, easy way to offer treatment options with greater detail, flexibility, and personal attention than you might otherwise be able to offer.
We’re also not limited to canine oncology. We also offer individualized consulting for internal medicine, neurology, dermatology, and emergency and critical care. Whether you’re dealing with an atypical case, a complex situation, or an overwhelming emergency, we can help.
At Hope Veterinary Specialty Services, we can be your lifeline. We can fill gaps and face challenges that overwhelm your practice, and improve outcomes for everyone involved.
Do you have any questions for me, either about our consulting services or an emergency? Please get in touch! You can email me at consults@hopevetspecialtyservices.com, and you can find our phone numbers on our homepage for urgent matters.