Cancer is considered the leading cause of death in dogs, and it’s tough to treat, especially in the later stages. Because of the complexity of this condition, early detection is crucial for a successful recovery.
However, it’s a condition that is usually difficult to detect, especially in its early stages. Plus, the common symptoms of cancer in dogs often resemble generic diseases and even relatively harmless conditions.
Still, it’s important to take note of the possible signs so you can get your dogs the help they deserve.
What is Cancer in Dogs?
In essence, cancer is a group of diseases that stem from abnormal cell growth. Normally, the body’s cells grow, divide, and die in a regulated cycle. But in cancer, these cells begin to multiply uncontrollably, disrupting this process.
From here, these abnormal cells can either form benign or malignant tumors.
In dogs, tumors can grow in any part of the body, from the skin to the organs within. Different types behave in many different ways.
How Do Dogs Get Cancer?
Canine cancer happens due to several reasons, namely genetic, age, environmental, and lifestyle factors. Because of its genetic factor, some dogs carry an increased risk of cancer, which includes:
Golden Retrievers
Rottweilers
Great Danes
Saint Bernards
Additionally, cancers in dogs can be caused by their age. Since the abnormal cells do take time to grow, they are often common in older dogs. This is because their immune systems weaken, their cells accumulate more DNA damage, and they experience increased cell division.
Environmental factors also play a role in increasing the risk of cancer, especially carcinogens. These chemicals are cancer-causing substances that can damage a dog’s DNA and stimulate tumor growth.
Carcinogens are common in a dog’s environment, especially in urban settings. Other common environmental factors include:
Secondhand smoke
Pesticides
Industrial pollutants and toxins
Excessive UV exposure
Poor air quality
How to Tell if Your Dog Has Cancer?
Each type of cancer has its own set of signs, some of which are shared across different types. Here are the common symptoms of cancer in dogs:
Unexplained Lumps or Bumps
You might see or feel lumps on your dog’s skin. It can be soft or firm, small or large. These growths can stay for months or grow rapidly. In some cases, they can ulcerate.
While not all growths are cancerous, they should still be checked. Depending on the location of these masses, they can cause significant discomfort for your dog.
Common cancers with this sign include:
Mast Cell Tumors. These lumps can be found on the skin as a noticeable growth or swollen mass. They often look like pimples.
Soft Tissue Sarcomas. STS can develop lumps on areas where soft tissue is present, such as the limbs, chest, and back.
Mammary Gland Tumors. These lumps can be found on the mammary chain of affected dogs, appearing as red masses.
Lameness and Limping
If your dog starts limping or having difficulty moving, then it can also be a potential sign of canine cancer. Some dogs also tend to hesitate and choose not to get up and walk at all.
While it can be thought of as a sprain, persistent pain and difficulty moving signal a much deeper issue.
Cancers with this symptom include:
Osteosarcoma. Common in large and giant dog breeds, canine osteosarcoma is a malignant bone tumor that weakens the bones and increases the risk of fractures.
Lymphoma. Lymphomas can affect the joints of dogs, resulting in pain, inflammation, and reduced range of motion.
Soft Tissue Sarcomas. These tumors develop on the soft tissues of dogs, significantly affecting their comfort and ability to walk.
Lethargy or Collapse
If your dog appears weak for long periods of time or collapses suddenly, then it might be an indicator of cancer. Abnormal growths inside a dog’s body can impact its bodily function, resulting in a much weaker state.
Your dog might also appear easily fatigued. This is often seen after some physical activity, which is commonly referred to as exercise intolerance.
This includes cancers such as:
Hemangiosarcoma. This type of cancer typically leads to internal bleeding in dogs, caused by the rupture of the blood vessels.
Heart Tumors. Abnormal growths on or near the heart can interrupt regular heart function, which impairs blood flow and oxygen delivery.
Lung Tumors. Lung tumors hinder proper breathing in dogs, especially if they obstruct the airways. This leads to shortness of breath and reduced oxygen supply.
Gastrointestinal Issues
Dogs can be picky eaters at times, but if your pup suddenly stops showing interest in food or starts eating more than usual, it can potentially point to cancer. For example, tumors and masses in the digestive tract can make eating uncomfortable.
This ultimately results in weight loss. Additionally, weight loss can also be caused by the cancer cells themselves draining your dog’s resources.
Other symptoms, such as vomiting and diarrhea, which are possible signs of gastrointestinal cancer, can also cause weight loss.
Cancers with these symptoms include:
Gastrointestinal Cancer. Cancers within the GI tract can impair the absorption of nutrients and make it painful for dogs to eat.
Lymphoma. Lymphomas within the digestive system can lead to a reduced appetite, changes in metabolism, and malabsorption of nutrients.
Liver Tumors. Similarly, tumors on the liver can result in loss of appetite and metabolic changes. These result in weight loss.
Neurological Changes
Tumors on the dog’s brain can significantly impact its behavior. Affected dogs may appear confused, restless, or even uncharacteristically aggressive. In other cases, they might also experience seizures.
Other changes include head tilting, an unsteady gait, and cognitive dysfunction.
Cancers with neurological changes include:
Brain Tumors. These masses physically damage the brain by compressing and applying pressure.
Pituitary Tumors. Pituitary tumors can also cause neurological symptoms by compressing the nearby structures of the brain.
Respiratory Symptoms
Your dog can also show chronic cough, labored breathing, shortness of breath, and wheezing as a result of cancerous growths. This often results from tumors in the lungs, airways, or chest cavity.
Respiratory cancers include:
Nasal Tumors. These tumors can obstruct the airways, cause irritation, and spread to other nearby areas.
Lymphoma. Mediastinal lymphoma can affect the lymph nodes in the chest, which compresses the lungs and causes breathing difficulties.
Lung Tumors. Abnormal growths along the lungs or the airways can cause obstruction, tissue damage, and fluid buildup.
Significant Bleeding
If your dog has cancer, bleeding can potentially come from its saliva, nasal discharge, or urine. It’s often a sign of internal bleeding, which can indicate a tumor of the blood vessels or an issue with blood clotting.
Canine cancers that cause bleeding include:
Hemangiosarcoma. Hemangiosarcoma causes the blood vessels to rupture, resulting in internal bleeding.
Melanoma. This cancer either causes bleeding through the invasion of blood vessels or ulceration.
Intestinal Tumors. These tumors can prompt nearby blood vessels to rupture. Tumors within the intestine can also ulcerate, leading to bleeding.
Unusual Odors
Foul odors can also prove to be a warning sign of cancer. Constant bad breath and oral issues are common symptoms. The reason for the foul odor can be the growths themselves, their ulceration, or the presence of secondary infections.
Cancers with this symptom include:
Oral Melanoma. The masses that grow along this area can ulcerate, which results in bad breath even with regular dental care.
Anal Sac Adenocarcinoma. A tumor in these sacs can lead to a foul odor by disrupting normal function. This results in a buildup of secretion.
Nasal Tumors. Tissue death, bleeding, and nasal discharge are often the cause of foul odor in nasal tumors.
Cancer Test for Dogs
These tests will help determine the type of cancer your dog has and will allow us to know what steps to take.
The process typically begins with a comprehensive physical examination. We’ll look for any signs of lumps, tumors, abnormal growth, and other physical abnormalities. While we take a look at your dog’s body, we’ll also check for its weight and ask you if it has experienced any behavioral changes.
We have diagnostic imaging tools to get a deeper look into your dog’s condition. This equipment helps us check your dog’s chest, bones, organs, soft tissues, joints, and other areas where the tumors could be located.
Our team can also do a fine needle aspiration, a method in which a sample of cells is collected and then examined under a microscope.
A biopsy is often the definitive test for diagnosing cancer. We do this by taking a larger sample of tissue from the mass or tumor. Once we get a sample, we’ll start examining it to determine the type of mass it is and other descriptive factors we need.
How Vets Treat a Dog with Cancer
Surgery, radiotherapy, and chemotherapy are the common treatment options for canine cancer. A combination of these three is typically done depending on the situation.
Surgery
Surgery is the main treatment option when dealing with tumors and masses located on the surface of your dog’s skin. The lump is surgically removed and then examined to determine the type of cancer your dog has.
This helps us determine if the cancer cells have spread to other parts of your dog’s body.
Radiotherapy
Radiotherapy targets and kills cancer cells in a specific area. By doing so, it hinders the spread of cancerous cells by destroying their DNA, while also minimizing damage to surrounding tissues.
Chemotherapy
Chemotherapy is one of the most effective ways to help slow the growth of cancer cells. It involves the use of drugs to target and destroy the cancer cells, slowing their growth and eliminating them entirely.
This process is also helpful in reducing the size of the mass prior to surgery.
“Even the smallest signs tell the biggest story. When something feels off, trust your gut.”
- Dr. Soheyl Simaei
Final Thoughts
From the smallest signs to the most prominent symptoms, cancer can affect our dogs in many ways. It all comes down to quick detection and efficient treatments to help our best friends recover and enjoy their life of adventure.
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