A mass in the stomach or intestines of a dog is usually due to a tumour, and most of them are cancerous. The outcome varies a lot depending on where the tumour is, what type it is and whether it has spread. These tumours are more common in middle-aged and older dogs.

Tumours of the stomach and intestines are uncommon in dogs. Cancers of the stomach make up about 1% of all cancers in dogs, and those of the intestines make up less than 10%. In most cases, a specific cause can’t be identified, but environment, food, genetics and other diseases may all play a role. The majority of intestinal tumours in dogs develop in the large intestine. Early diagnosis and treatment improve the chance of a good outcome.

 

Overview

What are digestive masses in dogs?

“Mass” in veterinary medicine is the term used for a lump or abnormal structure found in the body. Those affecting the stomach and intestines in dogs are usually tumours. In rare cases, it may be something else, for example, an abscess, a foreign body or the gut sliding inside itself (intussusception). Some types of tumours are more common:

• Lymphoma is the most common intestinal tumour type in pets. It can develop anywhere along the digestive tract, although it’s less common than other types in the stomach. This tumour can have two different appearances, as one solid mass or as abnormal cells spread throughout the intestinal wall.
• Adenocarcinoma is the second most common overall and is the most common in the stomach and large intestine. This tumour will often spread to other parts of the body.
• Leiomyosarcoma is a tumour of the muscle cells in the gut wall.

 

Symptoms

Symptoms of a digestive mass in dogs

Symptoms will depend on location, size and what organs are affected. Commonly signs are:

• Vomiting, sometimes with blood or a “ground coffee” appearance
• Loss of appetite
• Weight loss
• Lack of energy or lethargy
• Black, tarry stools
• Straining or urgency to poo
• Tummy pain (causing things like abnormal stretching or standing with an arched back)
• Swelling or redness of the anus
• Narrow or ribbon-like stools
• Excessive drooling
• Pale gums and anaemia
• Diarrhoea, sometimes with blood

Some tumours can also cause more unusual and indirect symptoms, such as

• Low blood sugar
• Excessive drinking and urination
• High blood levels of calcium

Risk

Dogs at higher risk of digestive masses

• Like most types of cancer, digestive tumours are more common in older dogs.
• Some breeds are at higher risk for certain types of cancer:
  • Stomach leiomyoma in Beagles
  • Stomach adenocarcinoma in Chow Chow, Rough Collies, Staffies and Belgian Shepherds
  • Intestinal leiomyomas in large breeds, especially German Shepherds
  • Intestinal adenocarcinomas in German Shepherds, Collies, Boxers, Doberman, Shar-pei, Poodle and Westies.
  • Rectal tumours in German Shepherds, Poodles, Great Danes and Spaniels
• Stomach cancer in dogs has been associated with long-term exposure to nitrosamines. These are present in tobacco smoke and can be produced in the body after eating ham and other cured, processed meats.

Diagnosis

Diagnosis of digestive masses in dogs

A mass may sometimes be noticed by a vet during a physical examination. It may also be found on imaging tests when trying to find out why a pet is unwell. Tests may then be recommended to gather more information:

• An ultrasound scan can be useful for finding out more about the location, size and general structure of a mass
• Endoscopy can be useful if the mass is in the stomach or end portion of the large intestine, and also allows biopsy samples to be taken
• X-rays may sometimes help, especially if the mass is suspected to be causing an obstruction
• Blood tests are useful to know how a mass may be affecting other organs and overall health
• CT or MRI scans can get more precise information about size and location of a mass and are the best way to look for the spread of disease

A definitive diagnosis of a mass allows for a more accurate prognosis and treatment plan. This requires a biopsy of the mass to be taken, usually through surgery. This is then examined and classified in a lab by a specialist.

 

Vet treatment

Vet treatment of digestive masses in dogs

Treatment depends on the type of mass, location and stage of disease.

• Surgery is the first treatment option, whenever possible. This can sometimes be recommended, even if disease has already spread, in order to improve comfort and quality of life.
• Chemotherapy is the treatment for diffuse lymphoma and can be used together with surgery for other cancerous masses.
• Radiation therapy may also be an option in specific cases, such as adenocarcinoma of the colon.

Other treatments may also be used to relieve symptoms of disease, such as pain relief and anti-vomiting medication.

 

Home treatment

Home treatment of digestive masses in dogs

A balanced, easy to digest diet and small, frequent meals often help improve digestion in dogs with masses.

 

Prevention

Can digestive masses be prevented in dogs?

Digestive masses do not have a specific cause that can be prevented.

As with most health problems, a balanced diet and healthy lifestyle will help prevent disease.

When it comes to stomach masses, it seems avoiding cured meats (such as ham and sausage) may help prevent them.

 

When to worry

When to worry about digestive masses in dogs

Take your dog to see a vet immediately if they show:

• Large amounts of blood in their diarrhoea
• Black or tarry stools
• Constant vomiting
• Weakness or lack of response when you interact with them
• Swollen abdomen

Speak to a vet as soon as possible if your dog:

• Continues to vomit even on an empty stomach
• Is constantly passing watery diarrhoea
• Loses interest in food
• Is quiet or lethargic
• Passes blood in their diarrhoea or vomit
• Is losing weight for no obvious reason

The vets and nurses at the Joii app are always available to give you advice and answer any doubts