There is no scarier diagnosis than cancer in regards to our canine companions.

We all know just how life altering cancer can be, so hearing this word come out of your vet’s mouth can cause the world to stop.

Once you accept this diagnosis in your furry friend, you will want to be prepared for anything that comes their way.

Whether this is eventual recovery or losing them to their disease, it’s important to be educated on all possible outcomes.

While we never want to discuss this, we should also discuss the possibility of euthanasia down the line.

At Charity Paws, our mission is to see dogs from rescues and shelters adopted, but sadly many dogs have been surrendered to these rescues because of health issues such as cancer.

These dogs are usually cared for in sanctuaries or in foster families until they must be euthanized.

To help you better understand when it may be time to euthanize your dog with cancer, let’s discuss the details of cancer in dogs, signs they may be dying, and how to know when your dog is ready to go.

Most Common Types Of Cancer In Dogs

Before we discuss when it may be time to put down your dog with cancer, we should first discuss the different types of cancer our dogs can develop.

Let’s briefly break down the most common types of cancer seen in our furry friends, and how each disease impacts their overall health.

Mast Cell Tumors In Dogs

Mast cell tumors are a cancerous tumor made up of mast cells, and they most often occur on the skin.

These tumors are typically localized, but they can spread to other parts of the body when left to progress.

The parts of the body that can be invaded include:

• The bloodstream
• Lymph nodes
• The spleen
• The liver
• The lungs

When this occurs, dogs will require systemic cancer treatment.

Not only can the cancer itself spread, but the mast cell tumors themselves can lead to full body complications.

These tumors release a chemical known as histamine, which plays a key role in the body’s immune response.

If these tumors become inflamed for any reason, the release of antihistamine can lead to a severe anaphylactic reaction.

Lymphoma In Dogs

Lymphoma is the most common cancer diagnosed in our canine friends.

This form of cancer is derived from the immune cells known as the lymphocytes, so the cancer circulates throughout the bloodstream and to multiple parts of the body.

This is considered a systemic cancer in dogs, but it most often impacts the lymph nodes.

It can also spread to:

• The GI tract
• The lungs
• The kidneys
• The skin

Lymphoma can go into remission with aggressive treatment, but it cannot be cured.

Hemangiosarcoma In Dogs

Hemangiosarcoma is a cancer of the blood vessel walls in dogs.

This cancer is highly malignant due to involving the bloodstream, and these tumors can develop virtually anywhere in the body.

Part of what makes this cancer so dangerous is the fact that most of the tumors will develop inside of the body, so the owners never see it coming.

This means that by the time the tumor is diagnosed in dogs, they are either too far gone to treat, or the dog is in a critical state from blood loss of the ruptured tumor.

Osteosarcoma In Dogs

Osteosarcoma is a highly aggressive bone cancer that can occur in dogs.

It most often develops on the bones of the limb, but it can occur on any boney surface throughout the body.

These tumors are known for being incredibly destructive to the bone it invades, as well as being unbearably painful.

Many dogs will experience bone fractures as this cancer invades the bone, and the cancer itself will often metastasize to other parts of the body.

The only way to stop the progression of this cancer is often amputation of the limb, as well as chemotherapy for the systemic disease.

Even with treatment, this form of cancer is often fatal.

Mammary Tumors In Dogs

Mammary tumors are a type of tumor in dogs that develop in the mammary glands of intact dogs (most often).

Up to 50% of these tumors are malignant, meaning the cancer is known to spread to other parts of the body.

This form of cancer often leads to a rapidly growing mass along the canine mammary glands, which will often become ulcerated and infected if treatment is not sought early on.

Even with treatment, survival time for this cancer is often less than 1 year.

The Different Stages Of Cancer In Dogs

To stage any form of cancer in dogs you must take into account the type of cancer they have, any evidence of spreading, as well as tumor sizing if there is a tumor present.

Each form of cancer has its own staging guidelines, so it is not as simple as simply ranking canine cancer from stage one to five.

For example, lymphoma in dogs is often based on how many lymph nodes are involved throughout the body, while hemangiosarcoma involves measuring both spleen and lymph node involvement.

Though each form of cancer in dogs will have its own grading system, you can typically expect a couple areas of the body to be considered.

In terms of metastasis, most vets will assess the lymph nodes and the lungs for any evidence of spread.

To allow for the most accurate staging for your dog’s cancer, your vet will often need to perform a few different tests.

This typically includes a fine needle aspirate of any masses or lymph nodes, biopsy of a mass, ultrasound, and x-rays.

Based on these tests, your vet can determine which stage of cancer your pup has, and which treatment approach will be best for their situation.

Understanding Your Dog’s Form Of Cancer

Just like in humans, there are multiple forms of cancer that can develop in our pups.

Each cancer impacts different parts of the body, behaves in a different way, and offers a different prognosis.

This is why it is so important to understand the specific details of your dog’s cancer, as this is the only way to have an accurate idea of what your dog could be experiencing.

Some forms of canine cancer are more aggressive than others, and others have a decent outlook based on how early you intervene.

You never want to simply assume what your dog is up against, so we always suggest asking your vet an array of important questions.

Some of these questions include:

• What is the name of my dog’s cancer?
• What parts of the body does this type of cancer affect?
• How far progressed is my dog’s cancer?
• Are there any treatment options for my dog’s cancer?
• What symptoms can I expect for this type of cancer, either through treatment or when left untreated?
• What is my dog’s prognosis with treatment? Survival time?
• What is my dog’s prognosis without treatment? Survival time?
• What symptoms can I expect if my dog is dying from this cancer?
• Can this type of cancer be cured?

By asking your vet the above questions, you will gain a better understanding of what’s to come for your dog.

Some of these answers can only be achieved if you perform necessary testing to determine the cancer stage, but others can be answered based on your vet’s knowledge of the condition alone.

How To Diagnose Cancer In Dogs

The standard diagnostic plan will vary with each form of cancer in dogs, but there are a few common options that your vet may explore.

Some of the most common ways to diagnose cancer in dogs include:

• Biopsy of abnormal tissue or tumor
• Needle aspirate of a mass or lymph nodes
• X-rays
• Blood testing
• Ultrasound
• MRI

In most situations, your vet will need to perform multiple diagnostics to get a concrete answer on your dog’s cancer.

Your vet will also need to know the status of your dog’s overall health before moving forward with treatment, which is another reason they will be inclined to perform multiple types of diagnostics.

Treatment For Cancer In Dogs

There are multiple forms of cancer that our dogs can suffer with, so there are just as many treatment approaches.

However, there are a few staple treatment options that your vet may explore when aiming to treat your dog’s cancer, or at least offer them more time with their disease.

Some of the most common treatment options for cancer in dogs include:

• Surgical removal of a cancerous mass
• Surgical removal of an invaded lymph node
• Chemotherapy
• Radiation therapy
• Amputation of the limb if there is a mass on the bone
• Palliative options including steroids, pain control, appetite stimulants, and any other options that will help your dog find relief. These options will not treat your dog’s cancer, but they will make their remaining time more comfortable. 

Each case of canine cancer is unique, so your vet’s treatment approach will be unique as well.

Your veterinary team will have the details of your dog’s situation, so we suggest asking them for specifics on your dog’s cancer treatment plan.

When Will My Dog’s Cancer Start To Make Them Sick?

If your dog has been diagnosed with cancer, you are likely wondering when they will begin to feel sick.

You may have already brought them to the vet for changed behavior, but you will want to be well aware of when they may start to struggle with the effects of their disease.

The answer to this question will vary based on how early their cancer was detected.

If your dog’s cancer was detected in the early stages of their disease, they may not experience any life altering symptoms if treatment is pursued immediately.

However, if you choose not to move forward with treatment for any reason, most dogs will develop significant symptoms within 1-4 weeks of diagnosis.

Due to the fact that canine lymphoma is the most common cancer on the list we discussed above, we can offer a rough timeline of how this disease tends to impact our little ones.

In most cases, many pet parents will bring their dogs into the vet when they stumble upon enlarged lymph nodes.

Your dog may not have any other symptoms at this point, but it’s still important to understand the progression over time.

First, your dog will often develop enlarged lymph nodes and lethargy due to the toll the disease takes on the body.

Within 1-2 weeks your dog may begin to experience symptoms such as weakness, anorexia, weight loss, and even vomiting.

These symptoms will often get worse and worse as the next few weeks pass, with many dogs often passing away within 2 months of diagnosis.

However, this only refers to dogs that do not undergo treatment.

Each cancer will vary in terms of the general timeline, but it’s safe to say that most dogs will develop symptoms of their cancer within 1-4 weeks of diagnosis if the disease is caught early on.

Keep in mind that if your dog is already experiencing changes in their behavior when the cancer is diagnosed, their symptoms will often continue to progress as the days and weeks go on.

The Signs Of A Dog Suffering With Cancer

Due to the fact that every type of canine cancer is so different, it’s important to have a general understanding of the symptoms you may see when your dog begins to suffer.

Many dogs with cancer will experience a common list of symptoms when they are in the late stages of their disease, ranging from anorexia to significant weight loss.

To help you identify when your pup may be struggling, let’s break down the common signs of late stage cancer in dogs below.

Your dog may be suffering with cancer if they are experiencing the following symptoms:

• Rapid weight loss
• Significant decline in appetite or complete anorexia
• Persistent diarrhea or vomiting
• Frequent lethargy or weakness
• Disinterest in activities they once enjoyed
• Limping that will not resolve
• Slowing down or having a hard time getting around
• Changes in breathing
• Any other changes in their daily behavior and habits

If your pup is experiencing any of the above symptoms after their cancer diagnosis, it may be time to start considering the possibility of saying goodbye.

If you are not yet sure or would like some additional support before you make this decision, you can always speak with your vet about their quality of life.

How Do I Know When To Put Down My Dog With Cancer

If you have gotten to the point in which you are considering euthanasia for your dog with cancer, there are likely a few factors at play.

You may have seen your dog’s health decline, they may no longer be acting themselves, and you may be concerned about them being in pain.

We never want our beloved pups to suffer, so making the decision to say goodbye can be the kindest option in these tough moments.

If your dog is experiencing any of the signs of suffering that we mentioned above, we think it may be time to have an important discussion with your vet about their prognosis.

If your vet thinks anything else can be done to prolong their life and minimize their discomfort, then it may be time to do just that.

However, if all options are off the table, it’s likely time to discuss the possibility of putting them to sleep.

We know this decision is impossible, so we encourage you to take your time and consult with everyone on your veterinary team.

We want you to not only feel supported when you make this decision, but to feel confident in doing so as well.

This is an unbearable situation to be in, but your furry friend will appreciate your love and support during this time.

Final Thoughts On When To Put Down A Dog With Cancer

A cancer diagnosis in your dog is not only life altering for your furry friend, but to everyone that loves them dearly.

When to euthanize a dog with cancer is always a hard question to answer.

Always look at their quality of life and if they are in pain or suffering.

We know how difficult this time is, so we encourage you to arm yourself with research and seek support from your veterinary team.