What are the signs of cancer in dogs?

What are the signs of cancer in dogs?

Cancer is a serious concern for many dog owners, and unfortunately, it is relatively common in dogs, particularly as they age. Spotting cancer early can make a significant difference in your dog’s quality of life and the effectiveness of treatment options. Here, we cover common signs of cancer in dogs, why it occurs, and what to do if you notice any concerning changes in your furry friend.

Why Does Cancer Occur in Dogs?

Cancer in dogs, like in humans, can result from various factors, including genetics, environmental exposure, lifestyle, and sometimes unknown triggers. Some breeds may be more predisposed to specific cancers, while age itself is a significant risk factor. When cells in a dog’s body grow abnormally and out of control, they can form tumours or spread to other organs, leading to a range of symptoms.

Common Types of Cancer in Dogs

Understanding the main types of cancer that affect dogs can help you better interpret symptoms and discuss concerns with your veterinarian. Some of the most common types include:

• Lymphoma: Affects the lymphatic system, part of the immune system.
• Mast Cell Tumours: These skin tumours can spread to other parts of the body.
• Melanoma: A form of skin cancer that can also occur in the mouth and on paws.
• Bone Cancer (Osteosarcoma): Common in large and giant breeds, affecting the bones.
• Haemangiosarcoma: Often found in the spleen, liver, or heart, typically with little warning.

Key Signs of Cancer in Dogs

Each dog is unique, but the following symptoms may indicate cancer. If you notice one or more of these changes in your dog, it is important to seek veterinary advice promptly.

1. Lumps and Bumps

• Not all lumps are cancerous, but any new lump should be checked by a vet, especially if it grows quickly, feels hard, or seems fixed in place. 
• Soft, movable lumps are often benign, but only a proper examination can determine a lump’s nature.
• Skin cancers, including mast cell tumours, may appear as raised bumps. Occasionally they can present as red, inflamed and ulcerative. 

2. Unexplained Weight Loss

• Weight loss without any changes in diet or exercise is often a warning sign. 
• Cancer can alter metabolism or reduce appetite, leading to noticeable weight reduction. 
• This symptom may indicate cancers affecting the digestive system, such as those of the intestines or pancreas.

3. Changes in Appetite or Difficulty Eating

• Dogs with oral cancers may have difficulty eating, chewing, or swallowing. 
• You may notice excessive drooling, bad breath, or blood in the saliva if there is a tumour in the mouth.
• A sudden lack of interest in food could indicate an internal cancer affecting appetite.

4. Lethargy or Decreased Activity Levels

• If your usually energetic dog is suddenly tired or reluctant to play, it could be a sign of cancer affecting their energy levels. 
• Although lethargy is a general symptom that can relate to many conditions, it is commonly associated with cancer. 

5. Difficulty Breathing or Persistent Cough

• Lung cancer or cancers that have spread to the lungs may cause breathing issues.
• Persistent coughing or difficulty breathing, wheezing, or panting without exertion can indicate respiratory distress related to tumours.

6. Swelling or Sores that Don’t Heal

• Persistent swelling, open wounds, or sores that don’t heal may be linked to skin cancers or other cancers affecting tissue. 
• Swelling around the face, limbs, or abdomen could also indicate tumours beneath the surface.

7. Bleeding or Discharge from Any Body Opening

• Blood or unusual discharge from the mouth, nose, ears, or anus can be alarming and may indicate cancer. For instance, nasal discharge or bleeding could be a sign of a nasal adenocarcinoma, while rectal bleeding might point to conditions such as colorectal cancer or anal sac adenocarcinoma.

8. Changes in Bathroom Habits

• Cancers affecting the bladder, kidneys, or digestive system can alter urination or defecation. 
• Blood in the urine, straining, or increased frequency of urination are concerning signs. Likewise, constipation, diarrhoea, or bloody stools could indicate cancers affecting the intestines or colon.

9. Limping or Lameness

• Limping, particularly in large breeds, may sometimes be a sign of bone cancer (osteosarcoma). If your dog favours one leg, shows visible swelling in the limbs, or appears in pain, further investigation is warranted, especially if rest doesn’t improve it.

10. Abdominal Swelling or Bloating

• A sudden, noticeable enlargement of the abdomen could indicate internal growths, such as a tumour on the spleen or liver. Abdominal bloating could also result from a fluid build-up caused by a tumour. Dogs with a distended abdomen may appear uncomfortable or have trouble lying down. 

11. Behavioural Changes

• Pain or discomfort may cause behavioural shifts in dogs. Dogs that were previously social may isolate themselves, growl, or snap when approached, or seem anxious or restless. Such changes can indicate an internal issue, such as pain caused by cancer.

What to Do If You Notice Signs of Cancer in Your Dog

If you observe one or more of these signs, it’s best to schedule an appointment with your vet. Here’s what you might expect:

• Physical Examination: The vet will conduct a thorough check to locate any abnormalities.
• Diagnostic Tests: Blood work, urinalysis, imaging (like X-rays or ultrasounds), and biopsies are common tests to identify or rule out cancer.
• Referral to a Specialist: In some cases, your vet may refer you to an oncologist (a cancer specialist for animals) for advanced diagnostic and treatment options.

Early diagnosis is essential for the best possible outcome, as it provides a broader range of treatment options.

Treatment Options for Canine Cancer

If your dog is diagnosed with cancer, the treatment approach will vary depending on the type and stage of the disease. Common treatments include:  

• Surgery to remove tumours
• Chemotherapy to target cancer cells
• Radiation therapy for localised tumours
• Immunotherapy to enhance the immune system’s response. 

In some cases, palliative care may be recommended to manage symptoms and maintain your dog’s quality of life. Your veterinarian will tailor the treatment plan to suit your dog's specific needs and overall health.

Preventing Cancer in Dogs: Is It Possible?

While not all cancers are avoidable, there are ways to reduce certain risk factors:

• Healthy Diet and Exercise: Keeping your dog at a healthy weight and feeding a balanced diet supports overall health.
• Regular Vet Check-ups: This helps detect changes early.
• Minimise Exposure to Carcinogens: Avoid exposing your dog to harmful chemicals, tobacco smoke, and excessive sun if they are a white or light-coloured breed.

Conclusion

Cancer in dogs is a serious health issue, but by staying informed about the signs, you can help detect it early, potentially improving outcomes. Always consult with your vet if you notice unusual symptoms, and remember that a cancer diagnosis doesn’t necessarily mean a poor quality of life. With advances in veterinary care, many dogs continue to lead happy, fulfilling lives after diagnosis. Proactive care, regular check-ups, and attention to your dog’s wellbeing are the best tools you have to safeguard their health.