Cancer: Intestinal

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Types and Pathology:

Adenocarcinoma, Leiomyoma and Lymphosarcoma are the most common types of intestinal cancer in dogs. Another type of cancer is called an adenoma, which may occur, but is very rare.

None of the canine intestinal cancer types remain limited to a specific part of intestine, with reports showing that cancer can be distributed all over the small and large intestine. In severe cases, associated organs as the stomach, esophagus, pancreas, liver etc too can be affected, leaving these organs with secondary cancerous developments.

It is still unknown exactly what causes cancer in a dog’s intestine. Some research studies suggest that viral infections, ulcerative lesions and sometimes drug residue causes a cancerous development, but it is yet to be confirmed through valid research. It is believed that severe inflammatory bowel disease, if it is left untreated for quite some time, may develop into intestinal cancer.


The severity and nature of symptoms for canine intestinal cancer varies by type, location and stage of development. Older dogs are predisposed to this type of cancerous development. Similarly it is believed that male dogs are more susceptible to intestinal cancer, especially to adenocarcinomas and lymphosarcomas. In one study, it was confirmed that some breeds such as Boxers, Shepherds, Poodles and Spaniels are more likely to develop colorectal tumors.

Generally, a dog with intestinal cancer exhibits common symptoms such as anorexia, vomiting, bloody diarrhea, weight loss, abdominal pain and tremors, ascites (fluid accumulation in the abdomen) and in some cases severe constipation. Different types of intestinal cancers result in the development of lesions.

Examination of these lesions clinically can help to confirm the presence of intestinal cancer, but this approach requires advanced diagnostic techniques. Adenocarcinomas cause spotted lesions which are thoroughly distributed on the stomach, small intestine, large intestine and in the rectum. Similarly, leiomyoma appears as firm, lobulated and white projections on the surface of the intestine.

Lymphosarcomas occur sporadically, and may arise at any part of intestine. Any intestinal surface affected by lymphosarcomas appear swollen and ulcerative. The cancer spreads rapidly to other systems and lymph nodes.


Recurring and incurable clinical signs of bloody diarrhea, vomiting (may be bloody); anorexia (loss of appetite) and progressive weight loss should be suspected for intestinal cancer. If the suspected dog shows signs of severe abdominal pain and the abdomen appears distended due to ascites, the dog should be examined and tested for cancer.

Studies relating to biochemical profiles, CBC, urinalysis, pancreatic enzymes level, then followed by detailed radiography and endoscopy can help to confirm the type of intestinal cancer. Sometimes, it is possible that other abdominal and gastrointestinal problems are misunderstood with canine intestinal cancer, thus it is highly recommended that diagnostic and treatment plans should be applied by a veterinary oncologist, and only on basis of differentiation vs. other possible causes for the symptoms.


Surgery is the preferred method for treating different types of dog intestinal cancer, but there are certain limitations. A resection should not exceed 4 – 8 cm in margins, while repeated surgical operations can result in a decline in the health status of an affected dog. A biopsy of tissue from the margins of cancerous resection and other organs is highly recommended to estimate the possible outcome of the disease.

Chemotherapy and radiation can help with a cure, but cannot be applied in all cases. Local lymphomas are treated well with chemotherapeutics, but a diffused form of a similar type of cancer can never be treated with chemotherapy. Similarly, anal adenocarcinomas respond positively to radiation therapy, but similar types of cancer in other parts of the intestine, if treated with radiation, can cause more rapid diffusion, resulting in making the cancer incurable.

Support with supplements and nutritive components, especially natural remedies such as C-Caps Formula can help to improve the ratings for the prognosis, in addition to helping to alleviate some symptoms. These components are usually only used as a way of improving the quality of life of the dog.


It depends upon the type and mode of treatment. Long term life expectancy cannot be expected, as the only cancer has the ability to penetrate the body, but also treatment options can have several complications associated with it. The recurrence of canine intestinal cancer is reported in most cases. It can recur even after the 3rd day of treatment, and as long as 10 months after treatment. Thus, the prognosis for intestinal cancer in dogs is rated, “Very Poor”.