Gastric Carcinoma in Dogs: Comprehensive 2025 Guide

Dogs

Health & Safety

•18 July 2025

Gastric carcinoma, also known as stomach cancer, is a serious but relatively rare condition in dogs. Typically affecting dogs aged 8 to 10 years and older, it represents less than 1% of all malignant tumours seen in our canine companions. While it can occur in any breed, certain breeds such as German Shepherds and others are more predisposed due to genetic factors. Additionally, exposure to nitrosamines, found in some preserved foods, may increase risk.

Understanding the different types of gastric cancer is key for diagnosis and treatment options, as is recognising early symptoms and knowing about current veterinary approaches to managing this challenging disease.

1. Understanding Gastric Carcinoma and Its Types in Dogs

Gastric carcinoma in dogs encompasses several tumour types. The most common type is gastric adenocarcinoma, which arises from glandular tissue and accounts for around 70 to 80% of stomach malignancies. This cancer primarily develops in the stomach wall and often spreads to nearby lymph nodes and other organs including the liver and pancreas.

Other types include:

Lymphoma: Originating in white blood cells, this is a frequently seen malignancy in the gastrointestinal tract, particularly in breeds like Boxers, Saint Bernards, and Bulldogs.
Leiomyosarcoma: Tumours in the muscular wall of the stomach, which may spread to the liver, spleen, and kidneys.
Mast cell tumours: Affecting digestive tract, skin, and lungs, these tumours involve immune cells that normally protect against allergens but can cause harmful tissue damage when malformed.

Recognising the type of tumour affecting a dog is critical for tailoring treatment and providing the most appropriate care.

2. Recognising Symptoms of Gastric Carcinoma in Dogs

Early detection of gastric carcinoma can improve outcomes, but symptoms are often subtle initially and may resemble other gastrointestinal issues. Common early signs include intermittent vomiting, sometimes with blood, reduced appetite, lethargy, and mild abdominal discomfort.

As the cancer progresses, symptoms often become more pronounced:

Persistent vomiting, occasionally with blood or abnormal colour
Weight loss and muscle wasting
Abdominal swelling or pain
Changes in bowel movements, such as dark or bloody stools
Increased vocalisation or irritability
Excessive licking or scratching potentially linked to discomfort

Because these symptoms may suggest multiple conditions, a thorough veterinary examination including imaging and biopsy is essential for accurate diagnosis.

3. Diagnosis and Treatment Options

Diagnosis often involves a combination of blood tests, ultrasound, endoscopy, and biopsy to confirm the presence and type of tumour. Early diagnosis is challenging but vital for effective management.

Treatment depends on the stage and type of gastric carcinoma:

Surgery: Partial gastrectomy to remove localized tumours is the primary approach when feasible.
Chemotherapy: Drugs such as carboplatin and 5-fluorouracil may be used post-surgery or when surgery is not possible to slow progression.
Palliative care: For advanced cases, treatments focus on improving quality of life and managing symptoms, including pain relief and nutritional support.
Experimental and targeted therapies: Emerging approaches such as toceranib show promise but require further research.

Veterinarians often recommend a multimodal approach, combining surgery and chemotherapy where possible, emphasising early detection to improve prognosis.

4. Prognosis for Dogs Diagnosed with Gastric Carcinoma

The prognosis remains guarded, as most dogs are diagnosed at advanced stages when metastasis has occurred. Median survival times following surgery generally range from a few months up to six months, though rare cases of longer survival exist with aggressive combined therapies.

Without treatment, survival times are typically very limited, underscoring the importance of early veterinary attention at the first signs of symptoms.

5. Promoting Responsible Pet Care and Awareness

Pet owners are encouraged to be vigilant about changes in their dog's appetite, vomiting, and behaviour, seeking veterinary advice promptly. Responsible care includes regular health checks and avoiding prolonged exposure to potentially harmful substances such as nitrosamine-containing foods.

Genetic predispositions mean that owners of breeds such as German Shepherds, Boxers, Saint Bernards, and Bulldogs should be particularly alert to early signs and consult their vet for tailored monitoring.

Through awareness, early detection, and advances in veterinary treatment, there is hope to improve outcomes and quality of life for dogs affected by gastric carcinoma.