Stomach Cancer In Dogs – Symptoms & Diagnosis

Stomach Cancers are part of a large group of cancers called ‘gastrointestinal (GI) cancers’ which means cancers originate in the GI tract. This could happen in any place all along the GI tract i.e. abdomen, small intestine, large intestine, pancreas, esophagus, biliary system, rectum, and anus. In general, gastrointestinal cancers arise because of the abnormal proliferation and deregulated replication of cells anywhere at the length of the GI tract.

Stomach tumors are rare and comprise less than 1% of all neoplasms in dogs. Stomach tumors may be either non-cancerous (benign) or pre-malignant or cancerous (malignant). Cancerous tumors of the Stomach are typically invasive, and aggressive and tend to spread to other organs.

The most rampant stomach malignancies are adenocarcinoma, leiomyoma, lymphoma, carcinoid, leiomyosarcoma, and GI stromal tumor (GIST). While Benign lesions include adenomatous polyps, leiomyoma, and gastric adenoma.

Stomach Adenocarcinomas are the most prevalent canine stomach malignancies. They are diverse, malignant, neoplasms that are most often located in the pyloric region and in the lesser curvature of the stomach. The initial clinical signs mimic those of other chronic gastrointestinal disorders. Adenocarcinomas generally occur in dogs more than six years of age. Indiscriminately adenocarcinomas affect all breeds of dogs and it is one of the most taxing tumors to diagnose and treat.

Symptoms are dependent on the type of stomach cancer

Stomach Adenocarcinoma:

• Abdominal pain
• intestinal bleeding and dark-colored stools
• syncope - Loss of consciousness
• Lack of coordination
• Anemia
• Fatigue/Seizures
• Weight loss
• Decrease in the reflex of appendages
• Muscle twitching
• Reduced ability or enthusiasm to exercise

Stomach lymphoma:

• Abdominal pain
• Loss of appetite/ Weight loss
• Rashes and other skin conditions
• Polydipsia/polyuria
• Fever
• Lethargy
• Breathing and/or digestive issues

• The complete cure of stomach cancers is really uncommon, but treatment can make your dog feel comfortable and there may be side effects.
• Radiation, chemotherapy, surgical options, or a combination of these modalities may be tried.
• Chemotherapy for Lymphoma:
  • Multi-drug CHOP protocol: Four antineoplastic agents are used in this treatment and they are simply called CHOP -
    • Cyclophosphamide
    • Doxorubicin hydrochloride (hydroxydaunorubicin)
    • Oncovin [vincristine]
    • Prednisone
• For higher-stage cancers, surgery is the only option followed by rescue chemotherapy.
• Prior to surgery, Radiotherapy may be used to shrink malignant cells or used post-op to cut off the resulting remission.
• Newer treatment protocols such as monoclonal antibodies, immunotherapy, Targeted drug therapy and are also available.

• Once the surgery is over, activities of your dog should be restricted for about 2 weeks to allow recuperation and incision healing.
• A restrictive e-collar can be used for 2 weeks.
• Home-cooked diet, with wholesome, nutritious foods as a substitute for commercial diets.

The causes of stomach cancer in dogs are varied so Prevention is not possible. Treatment and survival rates differ based on the type and severity of cancer.

Early detection and good overall health are the only ways to prevent GI cancer.

Stomach Adenocarcinoma:

• Boxer, Golden Retriever, German Shepherd, Terrier, Irish Setter, etc.
• Female dogs are more overrepresented. Medium to large breeds is more reported.

Stomach Lymphoma:

• Airedale Terrier
• Basset Hound
• Boxer
• Bulldog
• Beagle
• Bullmastiff
• Chow Chow
• Golden Retriever
• German Shepherd
• Poodle
• Rottweiler
• Scottish Terrier
• Saint Bernard

1. Causes:

For Stomach lymphoma:

• Exposure to carcinogens or toxic chemicals (1,4-dichlorobenzene, Adriamycin (doxorubicin) phenylbutazone)
• Radiation or living near large-scale waste treatment plants or electromagnetic fields exposure
• Exposure to herbicides, insecticides, animal repellents, and microbicides
• Certain viral infections (Retroviruses)

2. Types:

Primary Stomach cancer: Cancer that starts off within the stomach region is called primary stomach cancer. Most stomach cancers are destructive and are with high metastatic prospects are high. For example, stomach Adenocarcinomas.

Secondary stomach cancer: This originates in another organ and spreads or metastasizes to the stomach region.

3. Mortality:

Benign forms of stomach cancer mortality rate are almost zero. The highly destructive Stomach Adenocarcinoma should be diagnosed early and has to be treated promptly. Unfortunately, it has a high case fatality rate, and < 45% of dogs survive more than 6 months from the time of initial diagnosis.

4. Prognosis:

Prognosis can fluctuate depending on when the diagnosis is made and the severity of the stomach tumor. In general, if the tumor is diagnosed early on, prior to any metastasis, chemotherapy and radiation treatment may be successful. If there is any considerable metastasis, specialists may suggest against traditional treatment and will provide treatments to pacify the dog’s clinical signs.

Contact your vet right away, if you notice any of the following:

• Narrow or bloody/black / tarry stools
• Fluid build-up in the stomach (Ascites)
• Abdominal pain

• High protein diet with complex carbs and good fats
• Protein should comprise 40% of dogs’ calories. Fresh, lean protein (Lean white fish such as cod, grouper, haddock, lean cuts of beef, pork loin)
• Fats: Salmon, herring, mackerel, lake trout, tuna, and sardines
• Complex Carbs: Brown Rice, Oatmeal, Whole Grains, Sweet Potatoes, etc
• Vitamin-rich fruits and veggies: Legumes, snap peas, green beans, carrots, cauliflower, broccoli, cabbage, tomatoes, citrus fruits, Blueberries, strawberries, cherries, etc

Early diagnosis and prompt treatment offer the most favorable prognosis. This highlights the importance of stomach checkups as part of a regular physical examination of our pets. For benign neoplasm, the prognosis is excellent whereas for malignant stomach tumors outcome is poor. Most of the dogs die within 6months of diagnosis or every so often euthanized.