Intestinal Cancer (Adenocarcinoma) in Cats

By PetMD Editorial on May 27, 2009

Adenocarcinoma of the Stomach, Intestine, or Rectum in Cats

Adenocarcioma is a malignant tumor that may occur in the gastrointestinal (GI) system of a cat. It can occur in any part of the GI system, including the stomach, the small and large intestine, and the rectum. This tumor is rare in cats, but when it does occur older cats are the most commonly affected. No particular cat breed is known to be predisposed, though it is more common in males than females. The prognosis for cats with adenocarcinoma of the gastrointestinal tract is usually poor.

Symptoms and Types

Symptoms are most commonly related to the gastrointestinal system and include:

  • Vomiting
  • Weight loss
  • Poor appetite
  • Abdominal pain
  • Hematemesis (vomiting of blood)
  • Melena (black colored feces due to hemorrhage in the GI system)
  • Bright red blood in feces
  • Tenesmus (difficulty with defecation)


The exact cause is still unknown, this condition is classified as idiopathic.


Your veterinarian will perform a thorough physical exam on your cat, taking into account the background history of symptoms. You will need to give a thorough history of your cat's health and onset of symptoms. Blood tests, fecal tests and a biochemistry profile will be performed. The blood tests usually show mild to severe anemia, mainly due to gradual blood loss through the feces. A sample of the feces will also be examined under microscope to look for the presence of hidden blood. Contrast radiography (using a contrast chemical agent) may reveal the presence, location, and size of the neoplasm. Ultrasound is also a valuable tool in the diagnosis of adenocarcinomas of the gastrointestinal tract. Using ultrasound, your veterinarian may decide to take a fluid sample through a fine needle to examine for the presence of neoplastic cells in sample fluid. An endoscope is also sometimes used for sample collection. If none of the above mentioned procedures are helpful in confirming a diagnosis, your veterinarian may decide to perform surgery, which will ultimately confirm the assumed diagnosis.


Surgery is the treatment of choice in adenocarcinoma of the gastrointestinal system, but a cure is seldom achieved because metastasis is common in affected patients. In cases of adenocarcinoma of the stomach, it is often difficult to remove neoplastic tissue. In cases of neoplasm of the intestines, the affected portion is removed and the normal portions of the intestine are then sutured together. Chemotherapy may be advised but it is usually unsuccessful. Pain killers are advised for lessening the pain associated with this neoplasm.

Living and Management

If surgery is performed on your cat, you may need to return to your attending veterinarian every three months after the surgery. At every visit, your veterinarian will perform the physical examination, take X-rays, and perform ultrasound to see if the tumor is re-growing or not.

These tumors characteristically grow rapidly, metastasizing to other parts and organs of the body. In case of gastric adenocarcinoma, the survival time is usually two months, whereas in cases of intestinal neoplasm, few affected cats are reported to survive more than one year. However, survival time is variable and can only be predicted by your veterinarian after a complete evaluation of your cat.

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