Intestinal Cancer in Cats

Intestinal cancer is a term used to describe abnormal cell growth or tumors occurring in the gastrointestinal system. This growth can be benign or malignant. Malignant growths are considered cancerous and can cause severe issues, potentially spreading to other systems or vital organs. Benign tumors can still cause issues in the intestinal tract, including blockage, and may require removal. Intestinal cancer in cats and other companion animals is most common in the small intestine but can affect the duodenum, stomach, large intestine, colon, or rectum. Without early detection and proper treatment, the prognosis for a cat with intestinal cancer is poor, and the condition can be fatal. If symptoms are observed, seek medical attention immediately.

The symptoms of intestinal cancer in cats are very similar to other gastrointestinal issues. This can make diagnosis difficult. The most common symptoms are vomiting and abnormal stool, but viruses, parasites, bacterial infections, and exposure to toxins can cause these symptoms as well. As tumors grow or the cancer spreads, symptoms become more evident. Tumor growth that results in a rupture of the intestinal wall can cause internal bleeding, which can be seen in the animal’s vomit or stool. 

Symptoms Include:

• Vomiting

• Lack of appetite

• Weight loss

• Abdominal pain

• Diarrhea

• Blood in vomit

• Dark or black colored feces

• Blood in feces

• Constipation

• Trouble defecating

• Gas

• Abnormal stomach sounds

• Fever

• Abdominal mass or swelling

• Lethargy

• Pale gums and mucous membranes

• Anemia

• Dehydration

• Internal bleeding

• Death

Types

Several types of cancer can affect the gastrointestinal tract. The most common intestinal cancer found in cats is lymphoma. It is also possible for cancers found in any part of the body to spread, including to the intestines. Some of the more common types of intestinal cancer than occur in cats and other companion animals include:

• Adenocarcinoma

• Carcinoid cancers

• Gastrointestinal stromal tumors

• Hemangiosarcoma

• Leiomyosarcoma

• Lymphoma

• Mast cell tumors

• Plasma cell tumors

Tumors are caused by abnormal cell growth. The body naturally produces new cells in the gastrointestinal system, but when these cells mutate and refuse to stop production, it results in cancer. The exact cause of intestinal cancer in cats is not known. Studies suggest that environmental factors could be a possible cause, but no definitive information is available. Risk factors for intestinal cancer in cats include age, infection with feline immunodeficiency virus, and infection with feline leukemia virus. Males are slightly more likely to develop intestinal cancer as are some breeds, like Siamese.

The similarity of intestinal cancer symptoms with those of other conditions can make diagnosis difficult. Your veterinarian will rely on a differential diagnosis, which is a process that involves ruling out conditions until the issue can be identified. Be prepared to discuss your cat’s complete medical history, the symptoms you have observed, and the timeframes associated with those symptoms. A physical examination will allow veterinary staff to look for observable clues that might help rule out or identify the underlying cause of their condition. If your pet has intestinal cancer, an abdominal mass may be identified during the physical examination. An identified mass can suggest inflammation, cancer, or parasitic infection. Veterinary staff will also draw blood and complete a full blood panel. This can help identify infections, elevated white blood cell counts, and may rule out some conditions. 

If cancer or other conditions are suspected, x-rays or other imaging techniques will be used to determine which organs are affected and look for signs of tumors or other issues. Intestinal cancer is usually observable on an x-ray or ultrasound. Imaging methods can also aid in biopsy procedures, determine the extent of the cancer, and monitor its spread. If a tumor is observed, a tissue biopsy will help veterinary staff determine if the condition is benign or malignant. In harder to reach tumors, your veterinarian may need to aspirate or remove cells from the mass with a large needle. Analysis of the biopsied material will provide your veterinarian with the information they need to properly diagnose your pet.

The treatment method used when intestinal cancer is diagnosed will vary depending on the cancer’s location, severity, and staging. In some cases, treatment may not be possible, especially if cancer has spread to other systems in the body or is affecting one or more major organs. If treatment is a viable option, the methods used will target removal or reduction of the tumor. These treatments may be used in conjunction with methods designed to treat symptoms. Common treatments for intestinal cancer include:

Surgical Removal 

The most effective method of treatment involves surgically removing the tumor or tumors and repairing the damage it may have caused in the gastrointestinal tract. Although surgery can be a risky treatment option, it is the best method to remove the cancerous cells. Surgical intervention will require hospitalization. Your pet will be placed under anesthesia for the procedure and will be carefully monitored by veterinary staff. 

Chemotherapy 

If surgery is not an option, chemotherapy treatments may be used to shrink the size of the tumor. This treatment method has had some success in cats and other companion animals. In some cases, chemotherapy may be used in conjunction with surgery. This generally occurs when it is difficult to remove all of the cancerous cells using surgical methods. Chemotherapy can weaken the immune system and have a negative impact on your pet’s overall health, making the treatment somewhat risky. 

NSAID Pain Relievers 

Nonsteroidal anti-inflammatory (NSAID) drugs may be prescribed to reduce fever, pain, and inflammation. In some cases, NSAIDs have been shown to aid in shrinking tumors as well. This treatment is fairly low risk, but proper dosing for the animal’s size is needed to reduce the risk of side effects. 

Antibiotics

In cases which a tumor or cancerous growth has ruptured the intestinal wall or is causing tissue death, antibiotics may be prescribed. This type of medication is used to fight and prevent bacterial infections. This treatment method has a low risk of side effects, but will not directly target the cancer. It is prescribed if infection is a concern. 

Antihistamines 

Some tumors, like mast cell tumors, can release histamine in the body and cause a severe allergic reaction. Antihistamine drugs can help prevent the physical reaction and reduce discomfort associated with histamine release. This low-risk treatment does not target cancerous cells and is only used to treat symptoms. 

Intravenous (IV) Fluids 

To combat dehydration and lethargy, fluid therapy may be recommended. This symptomatic treatment is generally provided inpatient and for a shorter period of time. IV fluids are commonly used for many procedures, including surgery. There is a very low risk associated with using fluid therapy.

The prognosis for a cat with intestinal cancer can vary from poor to good. This depends on the location, severity, and stage of the cancer. In cases which all cancerous cells can be surgically removed, there is generally a better chance of recovery. If your cat is able to return to your home, ensure it receives a healthy diet. Proper nutrition may aid in healing. A special diet may also be needed while the cat recovers from intestinal surgery. Generally, soft foods are recommended. Follow all of your veterinarian’s instructions, including proper dosing of medication and returning for any recommended follow-up visits.

Intestinal cancer can be expensive to treat. If you suspect your cat has intestinal cancer or is at risk, start searching for pet insurance today. Brought to you by Pet Insurer, Wag! Wellness lets pet parents compare insurance plans from leading companies like PetPlan and Trupanion. Find the “pawfect” plan for your pet in just a few clicks!