Lung cancer is a serious disease that places both the health and well being of dogs at serious risk. The goal is to spot the clinical signs of the condition as soon as possible to give your pet the best chance of survival.
Like most forms of cancer, older dogs are more likely to develop the condition - usually at ten years old or more. It’s also been found that Boxer dogs have an increased risk of developing lung adenocarcinoma (cancerous tumors) than other breeds; although this disease can affect all dog breeds.
Let’s first look at the various symptoms and stages of canine lung cancer. Then, we’ll look more closely at the five main types of this type of cancer, as well as how to move forward once a diagnosis is received.
Cancer of the lungs is a progressive disease, meaning it gets worse over time. Unlike some other types of cancer, there are some concerning symptoms that arise in the earlier stages of primary lung cancer for dogs that should immediately alert you that something is wrong. However, you might not notice signs for some time, compared with squamous cell cancer types (e.g. skin cancer) that are immediately apparent.
As the disease progresses, the symptoms intensify and the need for medical attention increases overnight. The clinical signs are indicative of the lung cancer stage a dog is in, and these stages are…
- Early stage
- Middle stage
- Late stage
- Crisis mode
Early Stage Symptoms
- Coughing up blood
- Accumulation of mucus in the throat
- Unable to keep food down
- Rapid weight loss
- Total loss of appetite
- Difficulty making motor movements
- Difficulty inhaling
- Heavy yet shallow breathing
Middle Stage Symptoms
- No interest in anything around them
- Constantly trying to sleep - but difficulty in falling asleep and staying asleep
- Concerning weight loss
- Shortness of breath
- Trouble breathing through the nose
- Restless and fidgety
- Excessive thirst and panting
Late Stage Symptoms
- Preferring to be alone
- Limp limbs and weakness
- Nausea and vomiting
- Zero appetite whatsoever
- Frequent diarrhea
Crisis Stage Symptoms
- Epilepsy-like behavior
- Seizures that persist
- Inability to control bladder
- Incapable of keeping food down
- Difficulty walking around
- Purple tongue or blue gums/lips
- Struggling to breathe
- Fainting at random
Types of Canine Lung Cancer
There are five main types, which are:
- Epithelial Lung Tumors
- Larynx and Tracheal Tumors
- Metastatic Lung Tumors
- Nasal and Sinus Tumors
- Primary Lung Tumors
Now, let’s explore the two primary types in more depth. The two most common types in dogs are caused by epithelial lung tumors and primary lung tumors.
Epithelial Lung Tumors
One of the types of tumors are called epithelial lung tumors. Medically referred to as adenocarcinoma, this type of lung tumor is a prominent primary lung condition that accounts for three-quarters of all canine lung cancer diagnoses.
Adenocarcinoma tumors in dogs start out as abnormal growths in the epithelial tissue layer. This will only go away if surgically removed, followed by consistent radiation therapy.
Your dog's cancer specialists will determine the appropriate amount of time and the number of radiation therapy appointments your dog should undergo. The entirety of the epithelial lung tumor will be removed by surgeons, so radiation will be a follow-up measure for killing off any remaining cancerous cells in your dog’s epithelial tissue.
An adenocarcinoma lung tumor is malignant, so not only does it increase in size very quickly, but it is likely to metastasize. This occurs when cancerous cells travel around the body and new tumors form elsewhere. Usually, this infects the liver of dogs and then exits to move to other internal organs.
Primary Lung Tumors
Primary cancer of the lungs can take place in any part of the lung lobes. In the lungs of dogs, the number and type of lung lobes are different on each side. To the right, there are four different lobes, including the accessory, caudal, cranial, and middle lobes. To the left, canine lung lobes include only two lobes, which are the caudal and the middle lobes.
Primary lung tumors can become larger metastatic tumors, causing them to spread to other parts of the body. This is why primary lung tumors are so daunting. Primary lung tumors are the most concerning because not only do they have the potential to metastasize, but they can occur in any part of the lungs.
How Lung Cancer is Diagnosed
First, it’s down to you as a dog owner to pick up on any unusual behavior by your pet. If you notice changes in their eating, breathing, or general demeanor that is out of character, you should consider taking them to the vet for a health check - it’s best to be safe than sorry. If your dog is exhibiting any of the more worrying signs, like coughing up blood or persistent vomiting, contact an emergency vet as soon as possible.
When it comes to diagnosing the condition, the most helpful tool utilized by canine cancer specialists is something known as a thoracic radiograph. It's essentially a radiology tool for the chest, which gives specialists an inside look at the lungs of dogs.
After the thoracic radiograph test is conducted, an additional exam will likely be done as well in order to double-check the findings of the thoracic chest radiograph results. That's where the possibility of a CT scan, an MRI, or an ultrasonography come into play.
After an analysis of your dog’s health history is complete, the canine cancer specialists can move onto figuring out which treatment options are best for your dog’s situation. There are so many treatment options to choose from, including but not always limited to…
- Complete blood count exam
- Computed tomography scans, or CT scans
- Magnetic resonance imaging exams, or MRIs
- Other forms of blood work as deemed fit
- Ultrasonography tests
- Fine needle biopsies
A fine needle biopsy is where cells from the tumor are collected with a long, thin needle that is inserted through the surface of the skin and all the way down into the tumor. It will then remove cells or fluid which are then tested to determine whether it is cancerous or not. This can be used on all forms of cancer, including squamous cell types.
Though an ultrasonography has its own set of beneficial elements, most canine lung cancer specialists will opt for either a CT scan or an MRI. The reason for the preference of CT scans and MRI tests over ultrasonographic examinations is that the first two enable doctors to check for a potential malignancy of the lung tumors.
If tumors in dogs are malignant, they can become metastatic, thereby causing the spread of cancer from the lungs to other parts of the body. Cancer that spreads elsewhere becomes far more difficult to treat, primarily because it enters the lymph nodes. When cancerous cells latch onto lymph nodes, they can travel by way of the lymph nodes through the lymphatic system. As a result of this possibility, metastasis is something cancer specialists are eager to avoid.
Primary lung cancer treatment options are similar yet different to the ways that other forms of canine cancer are treated. First of all, surgical removal is the most straightforward way of eliminating the cancerous cells because it is a way of literally removing the cancerous lung tumor.
However, there are plenty of treatment options to choose from, including…
- Pain medications like NSAIDs
- Radiation therapy
- Surgical removal
Alongside medical treatment, other forms of pain management can be considered, such as the use of CBD oil for dogs. Your vet will be able to recommend dosages and the best form of administering the supplement for your pet. CBD oil cannot cure any disease, but can improve a dog’s quality of sleep, sense of wellbeing, relaxation, and can ease their pain. Many pet owners choose to administer CBD oil to their dogs to calm them when they’re in discomfort.
How Long Will My Dog Live?
The survival time fully depends on the type of tumor as well as the size of the mass in a dog's lungs. When tumors are in the early stage, can undergo surgical removal, and have not even come close to spreading to other parts of the body, dogs are expected to live for roughly twenty months.
Cancer in dogs at the intermediate stage poses more of a threat to their recovery rate, but it’s nowhere near as low as the prognosis of dogs in crisis mode. At this point, if the cancerous tumor is large but the cancerous cells have not metastasized, then dogs often live for about eight months or so.
When the tumors have grown in size and made their way into the lymph nodes of your dog’s lymphatic system, the prognosis is far lower, with the average survival time coming in at about two months. The main reason for this is the element of metastasis because once lung tumors spread throughout the body, it increases the difficulty of treating the cancer overall.
In late stage cases, dogs usually do not have an expected survival time of longer than one month after receiving a diagnosis. As always, early detection is a saving grace and the best way to increase the dog’s chances of survival is catching it sooner than later. However, at any stage of diagnosis, the survival time once a dog has lung cancer is unfortunately, usually, only a maximum of twelve months.
When to Say Goodbye
There is never a good time to put a beloved pet down. No loving dog owner in the world wants to say goodbye to their canine companion, because dogs become part of the family, and saying a final farewell to a family member is never an easy experience.
With all of that said, there are times when the euthanization of pets that are in an incredible and unbelievable amount of pain is the best thing for them. Of course, putting your pet down is always a last resort, and your vet and cancer specialists will do everything in their power to keep this option as far away as possible - but with severe diseases like cancer, it’s not always possible for long.
The only time this option is considered will be in situations where the primary lung tumors in dogs are untreatable, therefore making them fatal. When dogs are in a situation of this kind, their condition is marked as being terminal, meaning they will never recover or improve. At this point, they will be very unwell, and will likely have difficulty in doing the most basic of things like sleeping, eating, and breathing.
In these cases, where their condition will never improve, it’s in your pet’s best interest to free them from pain. When dogs are suffering from terminal cancer, they are in a great deal of discomfort. Losing your dog will be difficult for your family, but keeping your dog alive increases their suffering.
Should you want a second opinion on the suggestion of euthanasia, definitely follow your intuition and reach out to another canine cancer specialist for a second opinion - there may be other vets out there who believe another form of treatment might help. The more information you can gather, the more prepared you’ll be, even when facing a worst-case scenario.
The Bottom Line
Unfortunately, lung cancer is a terrible disease that often comes with a short prognosis. If it is discovered that your dog is suffering from the condition, have an honest talk with your vet about whether surgery and radiation therapy is likely to cure your dog of cancer or prolong their suffering.
Sources:Lung Cancer (Adenocarcinoma) in Dogs
Squamous Cell Cancer
The bronchial tree and lobular division of the dog lung
Lung Cancer in Dogs and Cats
When a Pet is Suffering from Cancer
Cancers and Tumors of the Lung and Airway in Dogs
Lung Tumors in Dogs
Dr. Ivana Vukasinovic
Doctor of Veterinary Medicine, University of Belgrade
Ivana Vukasinovic grew up in Serbia and attended the University of Belgrade where she received a degree in Veterinary medicine in 2012 and later completed surgical residency working mostly with livestock. Her first year of practice was split between busy small animal practice and emergency clinic, and after two more years of treating many different species of animals, she opened her own veterinary pharmacy where an interest in canine and feline nutrition emerged with an accent on fighting animal obesity. In her free time, she acts as a foster parent for stray animals before their adoption, likes to read SF books and making salted caramel cookies.
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The Innovet Team
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