Should I Treat My Senior Dog’s Cancer?

With more than 50% of dogs over the age of 10 receiving a cancer diagnosis, one of the few health concerns that you as a pet parent can take comfort in knowing, is that it is not your fault.¹ 

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Pet parents may find themselves thinking: “Is my dog too old for cancer treatment?” 

The answer to this question is often not a simple one, and depends on a variety of factors, including the specifics of the cancer diagnosis, the needs of your aging pet, and your capacity as a pet owner—both financially and emotionally. Aging takes its toll on our furry friends just as much as it does on humans; there is never just one right answer to this question, but rest assured that whatever answer makes the most sense for you as a pet owner, is the correct answer.

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How cancer type affects treatment needs for senior dogs

As with human cancer patients, dogs can have a variety of diagnoses that will make a huge impact on deciding on whether a senior dog’s treatment plan is worth putting them through it. 

Some cancers are highly treatable and are very likely to be brought into remission, while others are more complex and aggressive to treat. A dog that has a less aggressive form of cancer may not need treatment to continue living a happy, comfortable life for the rest of their silver years. Dogs that have more advanced cancer may benefit from treatment to get them to a more comfortable level.

Commonly diagnosed cancers in older dogs 

Some of the most frequently diagnosed cancers include Lymphoma, Mast Cell Tumors, Osteosarcoma, Melanoma, and Hemangiosarcoma. 

Lymphoma is a type of blood cancer that starts in the lymphatic system and can affect various parts of the body. There are many varieties of how this cancer can develop, with some forms being more aggressive than others. 

You can learn more about the basics of lymphoma in our post here. 

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Mast cell tumors are a pretty common skin cancer that affects the immune system. Mast cells are the part of the immune system that produce histamines which are the main factor in allergic reactions. Mast cell tumors have a wide range of behavior from curative with surgery to rapidly fatal. Many dogs who get one mast cell tumor will go on to develop more throughout their life.

You can learn more about mast cell tumors in our blog here.

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Osteosarcoma is a common bone cancer that makes up about 85% of diagnosed bone cancers. It is a fast-progressing cancer that spreads relatively early in its progression to other areas of the body, especially to the lungs. 

You can learn more about osteosarcoma in our post here. 

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Melanomas are a type of skin cancer that affects the cells that create pigment in the body in people, but it occurs most often in the mouth of dogs. This can be a very aggressive cancer in the mouth which may require many different types of treatment. Melanoma of the skin is generally a benign tumor in dogs and in many cases is curative with surgery.

You can learn more about melanoma in our blog here.

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Hemangiosarcoma is a type of cancer that affects cells related to the cardiovascular system.  Tumors from this kind of cancer usually grow in places like the spleen, liver, right atrium of the heart, and skin. This cancer can be rapidly progressing and often the first signs of disease are found in emergency. 

You can learn more about hemangiosarcoma in our blog here. 

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Quality of Life vs Cancer Treatment 

In every case, the most important fact to consider is the individual patient’s quality of life. A 12 year old Chihuahua mix will likely feel a lot more spry and lively than a 12 year old Great Dane. There are many aspects of a dog’s quality of life that will make an impact on whether going through treatment for cancer will be worth any strain or stress that comes along with it.²

Age versus overall health, what matters more? 

For many pet health care providers, the answer to that question is more often “overall health”. For a dog with a high quality of life, your vet may hesitate to recommend immediate treatment unless the circumstances prove necessary to do so, as any kind of treatment (mild or more aggressive) will disrupt your dog’s comfort, and it may make more sense to wait until a later time to start treatment. However, this is not typically the case with cancer, because it is usually best to start treatment before the disease is more advanced affecting quality of life.

The Quality of Life Scale is a system that was developed to help pet parents make these morally complex decisions regarding their aging dog’s health, based on how well their pet is able to communicate their needs. 

Often, this system is also referred to as the “HHHHHMM” scale, which stands for Hurt, Hunger, Hydration, Hygiene, Happiness, Mobility, and More good days than bad. The scale works by giving your dog a ranking of 0-10 in each category and calculating the total amount of points they’ve received. Typically, when a pet scores less than 35 on this subjective scale, it is a sign that your pet may be ready to cross the rainbow bridge, and that the best decision is to let them be and enjoy the time you have left. 

The Quality of Life Scale can also benefit pet parents who aren’t ready to say goodbye to their furry family members when a situation like cancer comes up. Using the Scale can help determine if your pet is being actively affected by the cancer diagnosis, or if they have the energy available to undergo treatment without it impeding their quality of life. 

We know our pets don’t have as long of a lifespan as we would like them to, but using the scale can help us make decisions for their health that will ensure that the time they have left is filled with love and comfort rather than pain or stress from treatments or medical problems. 

For more information on the Quality of Life Scale you can read our post about navigating euthanasia in dogs here. 

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Palliative vs curative treatment

While the idea of cancer treatment may bring up the idea of human cancer treatments—chemotherapy that seems to deteriorate the body more than it helps, hair loss, nausea, and other unfortunate side effects—treating cancer in dogs doesn’t mean that they’ll have to go through the same fight. For one, dogs take better to chemotherapy treatments than humans, so the side effects they experience are significantly less. And there are also many other approaches to treating cancer in dogs besides just chemotherapy. 

In comparison to human cancer treatment, where often a patient’s treatment is determined by what will cure them or get them into remission the fastest, even if it is a bit more aggressive of a treatment, pet cancer treatment is typically designed to get the animal back on their feet and comfortable as quickly as possible. 

The first, and biggest, choices a pet parent makes in regard to cancer treatment is to decide between palliative or curative care. While both options are viewed as treatments, palliative care focuses on providing comfort to the patient and does not work towards curing them. In contrast, curative, as the name suggests, is used with the hopes of “curing” or bringing the cancer into remission, and typically has a bit stronger of an impact on the body than palliative treatment, with the expectation that the patient is better off post-treatment. 

Palliative care is a great option to help keep your pet comfortable if you are concerned about your dog’s quality of life while undergoing treatment.

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How does cancer treatment affect a Senior Dog? 

There are many different ways to approach treatment for cancer and a lot of it does depend on the nature of the diagnosis. 

Chemotherapy

Chemotherapy is part of a treatment plan, and is often chosen when a cancer is systemic (meaning that it affects more than one part of the body), because chemotherapy is a whole-body treatment. Cancers like lymphoma, which is a type of blood cancer, are commonly treated with multiple chemotherapy drugs that work together to fight the cancer cells. 

For dogs of any age, most chemotherapy treatment plans will be prioritizing the patient’s comfort, so any side effects will be minimized wherever possible.

You can learn about chemotherapy and why it’s the first choice for dogs with lymphoma. 

Side effects of chemotherapy treatment for older dogs

While canine patients generally take well to chemotherapy there are some side effects that can happen to patients of any age, such as stomach discomfort, lethargy, and a weakened immune system. 

However, older patients should take any pre-existing conditions into consideration when choosing a chemotherapy treatment plan. Older dogs,14 years old or greater have been found to be may be a bit more sensitive to the potential side effects of treatment, prompting some additional support with anti-nausea medications or probiotics to help with any vomiting or diarrhea that may occur. 

Overall, it’s better to go with a personalized approach to the treatment for older dogs, and have plans in place for if, or when, the dog feels side effects. 

You can learn more about mitigating side effects of chemotherapy in our post here. 

Radiation 

Radiation is a treatment that helps with localized cancers where surgery isn’t possible or the tumor was not completely removed or can’t be safely accessed. Tumors in places like the brain or nasal cavity are commonly treated with radiation therapy. 

Radiation is often used in conjunction with another form of treatment, be that chemotherapy which is able to target more of the body systemically, or surgery, in which a majority of the tumor will be removed and then radiation after the initial procedure will work as a final pass to ensure that any remaining cancerous cells are taken care of in the body. 

Radiation can also be used as a form of palliative care in some situations to help shrink the size of a tumor and relieve some pain, helping a patient increase their quality of life with minimal intrusion.³

Side effects of radiation therapy in senior dogs 

Skin irritation is incredibly common with radiation therapy in dogs of any age as it can cause a blister type burn at the site of radiation. This can cause irritation in other tissues as well depending on the tumor location and surrounding normal tissue.³ Dogs will also lose their fur at the treatment site especially with tumors on the skin or just under the skin in the deeper tissues. Some dogs the fur will grow back a white color while others the fur never grows back and the skin is a dark color. 

It is important to note that most dogs that go through radiation treatment are put under anesthesia to receive the treatment. Senior dogs could have complications from anesthesia than younger patients if they have any underlying kidney or heart disease, so be sure to discuss any concerns with your vet.⁵ 

Surgery 

Surgery is a common first line treatment for tumors that are easily accessible and haven’t metastasized to other areas of the body yet. For example, melanomas are very effectively treated with surgery. 

Surgery does require that the patient be under anesthesia for most procedures, so it is important to talk with your vet about the particular strain that anesthesia can put on your senior pooch. In some cases, while it may be viable to have a surgical treatment for the particular type of cancer that a senior dog may have, it can be better to skip the surgery and go for an internal or less invasive treatment method if possible. 

Side effects of surgery for senior dogs 

Concerns that come with surgery particularly stem from any kind of anesthetic complications, so it is very important to discuss with your vet the risks that your dog may be susceptible to.⁴ 

Some other side effects include infection and incisional breakdowns where the surgical point opens back up. This can occur if dogs are too active after surgery or if they are able to lick the surgery site. Senior dogs can be more agile and active than you would expect, so it is important to follow your veterinarian's guidelines about decreased activity and the “cone of shame”.

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Learn about how ImpriMed helps vets provide personalized treatments for canine lymphoma patients.