Lymphoma In Cats: Symptoms, Diagnosis & Treatment

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Lymphoma is one of the most common feline cancers, with around a third of new cancer cases being diagnosed as lymphoma each year. But what is it, and is your cat at risk?

What Is Lymphoma?

Lymphoma is a type of cancer. In fact, it is thought to be the most common type of cancer to affect cats worldwide. It’s a cancer of the lymphocytes—a type of immune system white blood cell—and as these cells are so widespread, lymphoma can be found almost anywhere in the body.

Whilst all cats are at risk of lymphoma, there are a few things that increase a cat’s risk of disease. For instance, older cats are more at risk of lymphoma, with cats around 10-12 years being more likely to be diagnosed than younger cats. Male cats are also slightly more likely to get lymphoma, and unneutered cats, or cats that were neutered late in life, are also more likely to suffer with it.

This is partly because some types of lymphoma are more likely in cats that have been infected with Feline Leukemia Virus (FeLV) and, to a lesser extent, Feline Immunodeficiency Virus (FIV). Other reasons that a cat may be more likely to get lymphoma have been discussed, but none have been proven.

In 2002, a paper suggesting a link between nicotine from smoking and lymphoma was published, but a recent 2020 paper found no link between the two.

Common Sites Of Lymphoma In Cats

Sites of lymphoma in cats

Lymphomas most commonly develop in the gastrointestinal tract, but they can develop in several sites around the body.

Feline lymphoma can be found in several different sites. Each ‘type’ of lymphoma is named for the area that it is found.

  • Alimentary or Intestinal Lymphoma– By far the most common lymphoma in cats, this type of lymphoma affects the guts. Intestinal lymphoma can actually be split into two further types- small cell lymphoma, and large cell lymphoma. Small cell lymphoma is a slow-growing, cancer-causing gut thickening, whilst large cell lymphoma creates hard tumours in your cat’s guts and/or stomach. Large cell lymphoma in cats is far more aggressive and has a poorer prognosis.
  • Mediastinal Lymphoma– This type of lymphoma grows in your cat’s chest, usually between their lungs. Over time, it can grow large and put pressure on the lungs and heart. It’s more common in younger cats and those with FeLV.
  • Renal Lymphoma– Lymphoma can also affect the kidneys, causing symptoms similar to chronic kidney disease as the kidney cells are replaced by cancer cells.
  • Nasal Lymphoma– Nasal lymphoma affects the nose of cats and usually starts as a facial swelling. In about a quarter of cases of nasal lymphoma, the cancer has spread to other parts of the body.

Miscellaneous Lymphoma Types In Cats

There are also less common forms of lymphoma affecting the nerves, the lymph nodes, or other sites in the body. Multi-nodal lymphoma/multicentric lymphoma, cutaneous lymphoma, mesenteric lymphoma, ocular lymphoma, and spinal lymphoma are all other types of lymphoma in cats. There is some evidence that cutaneous lymphoma in cats is becoming more common.

Symptoms Of Lymphoma

The symptoms of lymphoma in cats vary slightly depending on the site that’s affected, although all types of lymphoma in cats can cause weight loss, lethargy, and a poor, dull, or greasy coat. Cats with lymphoma may have an increased or decreased appetite, or you may notice no change in appetite.

Signs of Lymphoma in Cats

Cats with lymphoma will show general signs of illness, with a dull coat, lethargy, and changes in appetite being common symptoms.

The most common type of lymphoma- gastrointestinal lymphoma- affects the gastrointestinal tract so causes weight loss, diarrhoea, and vomiting.

Changes in drinking and urination habits can be a sign of renal lymphoma, although all lymphomas have the potential to cause an increase in drinking. Neurological signs, such as seizures, head pressing, and blindness can occur with nasal lymphoma and nervous system lymphoma.

A change in respiratory rate, difficulty breathing, coughing, panting, and difficulty exercising can occur with mediastinal lymphoma.

Read More: Heavy Breathing Cat: The 3 Types of Heavy Breathing and What they Mean

And swelling of the nose, discharge from the eyes and nose, and sneezing or nosebleeds can occur with nasal lymphoma.

Other symptoms of lymphoma include:

  • Weight loss and poor condition
  • Change in thirst, usually increased
  • Change in appetite, usually anorexia
  • Vomiting and diarrhoea
  • Increased urination
  • Sneezing
  • Coughing
  • Increased respiratory rate, effort, or noise
  • Nose bleeds and mucus discharge from the nose
  • Facial swelling
  • Seizures
  • Confusion, disorientation
  • Blindness
  • Depression and lethargy
  • Swollen or painful lymph nodes
Diagnosis of Lymphoma in Cats

It’s important to have your cat tested by a veterinarian to reach a final diagnosis.

Because these clinical signs are vague, and can be symptoms of many other diseases, your veterinarian will need to do further testing if they suspect your cat has lymphoma. They will likely start with a complete blood count, as changes in the lymphocytes may be recognised here. Ultrasounds, x-rays and CT-scans can help by allowing your vet to see any abnormalities in more detail.

Your vet will also want to take a biopsy of the affected area- by harvesting a few cells with a fine needle aspirate or a small lump via a surgical biopsy, they should be able to get a diagnosis. The tumour is then ‘graded’ to describe how aggressive it is- low grade lymphoma is less aggressive than high grade.

Lymphoma In Cats Treatment

Feline lymphoma can be treated with surgery, chemotherapy, or radiotherapy, depending on the type, grade, and location of the cancer. The difficulty with treating lymphoma in cats is that the cancerous cells are generally spread over a large area, so it’s not as simple as just ‘cutting them out’.

Chemotherapy is the most common lymphoma treatment plan in cats, as it can help to kill all cancer cells including those not in the main location of the tumour. Chemotherapy for low-grade lymphoma usually involves tablets, whilst high grade lymphoma is more likely to require injectable chemotherapy.

Cats tolerate chemotherapy very well and don’t suffer too badly with side effects- they rarely lose their hair or appear sick, but some will get mild vomiting or diarrhea. Oral chemotherapy with prednisone and chlorambucil is suitable for small cell lymphoma, but the more aggressive types of lymphoma need a more intense treatment including injectable chemotherapy drugs. This chemotherapy protocol is commonly called a ‘CHOP’ protocol and includes cyclophosphamide, doxorubicin, prednisolone, and vincristine.

Treatment of Lymphoma in Cats

There are several options for treatment of lymphoma in cats, with treatment routes varying in aggressiveness and which type of lymphoma they address.

We have listed the most common type of therapy pursued and the average survival times below:

  • Small cell GI lymphoma: oral chemotherapy. 80% go into remission for 2-3 years
    Large cell GI lymphoma: aggressive chemotherapy, 50% with some remission, survival 3-10 months.
  • Mediastinal lymphoma: aggressive chemotherapy, survival is 3 months if cat has FeLV, 9-12 months if no FeLV.
  • Nasal lymphoma: chemotherapy or radiation therapy. 80% respond well, survival up to 2 years.
  • Renal lymphoma: aggressive chemotherapy improves symptoms in around 60% patients, but survival is typically 6 months.

Conclusion

Lymphoma is a common and serious cancer in cats. The most common type of lymphoma is gastrointestinal lymphoma, and it’s poorly understood.

However, mediastinal lymphoma and renal lymphoma are both associated with feline leukaemia virus infection, so it’s recommended that you cover your cats with the FeLV vaccination to help prevent lymphoma.

Frequently Asked Questions

How long do cats with lymphoma live?

Depending on the type of lymphoma and the response to chemotherapy, cats with lymphoma can live for up to three years. Renal and mediastinal lymphoma have a poorer prognosis, and even aggressive chemotherapy can sometimes only buy these cats six months.

Is lymphoma in cats curable?

Feline lymphoma cannot be cured. However, about 80% of cats with small-cell GI lymphoma go into remission for two-three years if treated with chemotherapy. The other types of lymphoma are less likely to go into remission and the remission is shorter.

How long can a cat live with untreated lymphoma?

Depending on the severity of the symptoms, it may not be appropriate to deny treatment to a cat with lymphoma and your vet may recommend euthanasia to protect your cat's quality of life if treatment is not pursued. However, cheap and simple at-home steroid therapy can be used to reduce symptoms and buy the cat some time- typically a month or two.

How common is lymphoma in cats?

Lymphoma is common in cats, but frequency varies country-to-country. In some countries, it is the most common cancer, in others it is second or third most common. Around 15-30% of new tumours in cats are thought to be lymphoma.

About Dr. Joanna Woodnutt, MRCVS

Dr. Joanna Woodnutt (MRCVS) is a small animal veterinarian and writer who is passionate about helping owners to learn more about their pets in order to improve animal welfare. She loves to write and wants to empower owners to make the best decisions for their pets by giving them all the information they need. In her spare time, she takes consultations on the small island of Guernsey.

2 thoughts on “Lymphoma In Cats: Symptoms, Diagnosis & Treatment

  1. Lorraine

    I believe that my 17 year old Siamese boy recently passed away from lymphoma, but I am not sure. The first signs that something was wrong was about a month and change before he passed. He was starting to drink more water and urinate more, which increased greatly over time. He would sometimes urinate 10-12 times in one day. I had a full lab panel drawn on June 5, and the only thing off was an incredibly low platelet level, and very high lipase. He also occasionally had blood come out of his penis. His appetite never changed, and he continued to eat normally, even right up until the day before he passed. I took him for an ultrasound on June 16, which sadly showed a mass in his intestine. The night before he went into a coma, I came home to several spots of blood on the carpet, where he bled from his penis. I don’t think there was anything that could have been done, besides surgery, and that was not an option. What are your thoughts on this?

    Reply
    1. Mallory Crusta

      Hi Lorraine, unfortunately, we can’t say what led to your cat’s death. I would recommend talking with a veterinarian about this, giving them all of the information you’ve provided here, and seeing what they think. Ideally, this person would also have access to the full lab panel and the ultrasound results.

      Reply

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