Possible Signs My Dog May Have Cancer

Possible Signs My Dog May Have Cancer

Dogs are cherished members of our families, providing companionship, loyalty, and unconditional love. Just like humans, dogs can face health challenges, and one of the most concerning conditions is cancer. Canine cancer is a complex and multifaceted disease that can affect dogs of all breeds and ages. Recognizing the early signs of cancer in your furry friend is crucial for timely diagnosis and effective treatment. 

It is not new to our knowledge that if a dog is beyond the age of 10, there is 50% of your furry friend to develop cancer. Studies have shown that senior dogs face many health problems such as arthritis and cognitive decline, but cancer is, unfortunately, one of the most common. Although one in four dogs will develop cancer at some point in their life, this disease will strike almost half of all dogs over the age of 10. Several research studies state that this is the leading cause of death in senior dogs.

However, it should be noted that cancer is not exclusive to older dogs. It should be noted that it may occur in dogs regardless of their age. With this, knowing how to look for indicators of the disease is very much critical. 

Possible Signs of Cancer in Dogs

Understanding Canine Cancer

Cancer in dogs is characterized by the uncontrolled growth of abnormal cells that form tumors. These tumors can be benign or malignant, with the latter being more concerning as they can spread to other parts of the body. The types of cancer that affect dogs are diverse, ranging from skin tumors to organ-specific malignancies. 

On occasion, cancers will be visible from the outside. But, at other times, these are hidden deep within the dog’s organs and tissues. Early identification and treatment, on the other hand, are critical in protecting your dog’s health and quality of life.

Signs of Canine Cancer

Unexplained Weight Loss. One of the initial signs of canine cancer is unexplained weight loss. If your dog is losing weight despite maintaining a regular appetite, it could be indicative of an underlying health issue, including cancer. Cancer cells consume a significant amount of the body’s energy, leading to weight loss even when the dog is eating normally. 

Some tumors situated in the mouth, throat, or intestinal tract can create challenges in eating, swallowing, and food digestion in general. Moreover, these tumors within the digestive tract may result in symptoms such as diarrhea, vomiting, or reduced absorption of nutrients from the intestine, which all contribute to weight loss.

Lumps and Bumps. Cancerous lumps or growths on your dog's body should never be ignored. While not all lumps are cancerous, any new growth or change in size, shape, or texture should be examined by a veterinarian. Skin tumors are relatively common in dogs, and early detection can be critical for successful treatment.

Most of the time, cancerous lumps develop in the skin, digestive system, and the breast of female dogs. Some lumps and bumps will be benign such as lipoma. On the other note, those that are malignant, or cancerous, are the mast cell tumors and carcinomas.

Changes in Appetite. A sudden change in your dog’s eating habits, whether it be a loss of interest in food or increased appetite, can be a sign of an underlying health issue, including cancer. Studies have shown that cancer can significantly impact a dog’s appetite due to the direct effects of the disease. 

Most of the time, cancer often involves complex metabolic changes, leading to conditions like cachexia, a severe wasting syndrome characterized by weight loss and muscle atrophy. 

Lethargy and Fatigue. Cancer can cause systemic effects on a dog’s body, leading to lethargy and fatigue. If your once-active dog becomes increasingly tired, it may indicate an underlying health problem. Regular observation of your dog's energy levels is crucial for detecting subtle changes.

Persistent Coughing or Difficulty Breathing. Respiratory symptoms, such as a persistent cough or difficulty breathing, can be indicative of lung or heart-related cancers. Dogs, like humans, can develop tumors in their respiratory system, leading to respiratory distress. 

With that, cancer may induce coughing in dogs, making it essential for any pet displaying persistent coughing to receive prompt veterinary attention. Such a persistent cough might indicate a tumor exerting pressure on an airway, the presence of fluid in the lungs, or the development of multiple lung tumors.

Changes in Bathroom Habits. Changes in your pet’s bathroom routine warrant attention for early detection. Various forms of cancer can bring about changes in your pet’s potty habits, ranging from an augmented need for bathroom breaks to instances of constipation.

As an example, for instance, cancers affecting the gastrointestinal system may induce diarrhea and/or constipation. In the same manner, cancers affecting glands such as the adrenal, pituitary, or thyroid glands, as well as those affecting the liver or kidneys, may heighten thirst in dogs, leading to an increased frequency of urination. In cases of urinary system cancer, there may be an elevated urge to urinate coupled with urethral obstruction, making urination challenging.

Consequently, pets with urinary cancer may experience frequent urination, indoor accidents, or apparent straining during the urination process.

Lameness or Difficulty Moving. Lameness in dogs is frequently attributed to cancers with various types of tumors affecting the skin and subcutaneous tissues. If you observe abnormal limb usage in your dog, it is crucial to promptly seek veterinary attention, particularly if the issue is not immediately resolved.

Abnormal Odors. Unpleasant odors emanating from your dog, whether from the mouth, ears, or any other part of the body, can be a sign of infection or cancer. Oral tumors, for example, may cause foul breath, while skin tumors can produce abnormal smells. In the same light, gastrointestinal cancers, or those cancers affecting the digestive tract, can lead to changes in breath odor or emit unpleasant smells either through feces or vomit. Anal gland tumors also tend to produce distinct, unpleasant odors. 

Changes in Behavior. Dogs with cancer may exhibit changes in behavior, including increased irritability, aggression, or withdrawal. Pain or discomfort associated with the disease can influence your dog’s temperament and interaction with family members and other pets.

Essentially, lack of energy or lack of interest in the things that used to bring your pet joy: accidents in the house; changes in sleep patterns; pacing; increased aggression or grouchiness; increased sleeping time; or any other abrupt changes in behavior—can be subtle signs of brain cancer or cancer pain.

Furthermore, seizures or tremors can also be a sign of brain cancer. Most of the time, these seizures can often be missed by pet parents. Some of the indicative signs that a pet may have experienced a seizure include twitching, loss of balance, temporary blindness, and excessive drooling.

Difficulty Swallowing or Eating. Tumors in the mouth or throat can make swallowing painful or difficult for dogs. If your dog shows signs of discomfort while eating, drops food from the mouth, or experiences unexplained drooling, it’s essential to investigate further.

Oral cancer in dogs results from the abnormal proliferation of cells in the mouth. The dog’s mouth comprises various cell types (skin, bone, fibrous) and tissues (hard and soft tissues), all of which can undergo uncontrolled growth, transforming into cancer cells that invade surrounding tissues. Furthermore, the prevalent types of oral cancer in dogs include oral melanoma, squamous cell carcinoma, ameloblastoma, and oral sarcoma, with melanoma being the most frequently diagnosed. Studies have shown that mouth cancer is relatively common in dogs, accounting for 6% of all canine cancer cases.

Identifying oral cancer in dogs involves recognizing large, often bleeding masses within the mouth. These growths can manifest in various regions of the mouth, but the gingiva (gums) is the most frequent site. The masses may exhibit pigmentation or lack pigmentation and present either a smooth or cauliflower-like texture.


In sum, cancer in dogs is a complex and varied spectrum of diseases that can significantly impact the well-being of our canine companions. The signs and symptoms of canine cancer are diverse, ranging from subtle changes in behavior to more overt physical manifestations. Recognizing these signs early on is crucial for a timely diagnosis and intervention, ultimately influencing the prognosis and quality of life for affected dogs.

While the prevalence of cancer in dogs is a sobering reality, advancements in veterinary medicine, research, and increased awareness among pet owners have contributed to improved diagnostic techniques and treatment options. Regular veterinary check-ups, coupled with attentive observation of a dog’s health and behavior, play a pivotal role in early detection.

It is important for pet parents to understand that cancer in dogs is not a one-size-fits-all scenario. Different types of cancer exhibit varied behaviors, growth rates, and responses to treatment. Therefore, a tailored and comprehensive approach to diagnosis and management is essential.

The emotional connection between dogs and their owners is profound, making the journey through a cancer diagnosis and treatment emotionally challenging. Yet, it is precisely this bond that often motivates owners to explore available options, seek expert veterinary care, and provide the best possible support for their furry friends.

Ultimately, in this shared journey between dogs and their human companions, the unwavering love and commitment that define the human-animal bond endure, offering hope, resilience, and the possibility of a brighter, healthier future for our beloved canine friends.