When to euthanize a cat with lymphoma

It is time to talk to your vet about euthanasia when a cat with lymphoma has stopped responding to treatment and is having more bad days than good ones: not eating for days, losing weight and muscle, working to breathe, or vomiting or having diarrhea that medicine no longer controls. The diagnosis itself is not that moment. Some cats with lymphoma live comfortably for years and others for only weeks, and which kind your cat has matters a great deal.

The decision is made with your veterinarian or veterinary oncologist, who can tell you what is left to try and what the coming days are likely to hold.

A diagnosis is not the moment

Lymphoma is a cancer of the lymphocytes, a type of white blood cell. It is one of the most common cancers in cats. In older cats it is found most often in the intestines, and it can also affect the chest, kidneys, nose and lymph nodes.

Treatment usually aims for remission, which means the signs go away for a time, not for getting rid of the cancer for good. Many cats feel well during remission. For the condition as a whole, see our guide to lymphoma in senior cats.

Small-cell and large-cell lymphoma are very different

The biopsy or cell sample tells the vet which type your cat has. Ask, because the answer changes what you should expect.

These are commonly reported ranges and they vary widely from cat to cat. Your own vet, who knows the type, the location and how your cat has responded so far, gives the real prognosis.

With small-cell lymphoma, the decision usually comes after a long good stretch. The sign that things are changing is a slow slide that treatment no longer stops: weight that keeps dropping, or vomiting and diarrhea returning. A minority of cats treated for small-cell lymphoma later develop the faster large-cell form.

With large-cell lymphoma, things can change within days. It helps to decide early, while your cat still feels well, what you will do when treatment stops working.

What coming out of remission looks like

A relapse usually looks like the illness did at the start. Watch for:

• Appetite fading again, or interest in food but walking away after a few bites.
• Weight loss on the scale, even a small amount.
• Vomiting or diarrhea coming back after a settled period.
• Faster breathing at rest.
• Lumps or a firm belly that the vet could no longer feel during remission.
• Sleeping more, hiding, or grooming less.

Tell your vet early. A relapse can sometimes be treated with a different medicine or protocol, often called rescue treatment. Second remissions tend to be harder to reach and shorter than the first, so ask what the realistic chance is before you agree to it.

Signs that lymphoma has moved past what treatment can hold

• Not eating for days, including favorite foods, in spite of anti-nausea medicine and appetite stimulants. See why an old cat stops eating.
• Weight and muscle loss, with the spine, hips and shoulder blades standing out.
• Labored breathing. Lymphoma in the chest can cause fluid to collect around the lungs. Breathing becomes fast and shallow, the belly heaves, or the mouth opens.
• Vomiting or diarrhea that no longer responds to the medicines that used to settle it.
• A swollen or painful belly.
• Withdrawal: hiding, no longer grooming, no interest in you or in a favorite spot.
• Weakness that keeps the cat from reaching the litter box or food.
• Heavy drinking, wobbliness or seizures, which can occur when lymphoma involves the kidneys or the nervous system.

No single sign confirms that the end has come. Several together, getting worse in spite of treatment, are what vets mean when they say the lymphoma is no longer under control.

What to review with your vet before deciding

• Nausea and appetite. A nauseated cat will not eat however hungry it is. Ask whether both have been treated as fully as they can be.
• Vitamin B12. Cats with intestinal lymphoma are often low in it, which can dull appetite further. Vets can test for this and treat it.
• Steroids. A steroid alone can shrink lymphoma and bring appetite back for a while. If chemotherapy is still a possibility, ask before starting one, because steroids given first may make chemotherapy work less well.
• Chemotherapy, if you ruled it out early. Cats generally tolerate it better than people do and most keep their coat. The aim is good time, and vets adjust or stop treatment if a cat is feeling unwell on it.
• Draining fluid from the chest. This brings quick relief, but the fluid returns if the lymphoma is not responding.
• Pain relief. Vets have pain medicines made for cats.
• A feeding tube. It can make sense when treatment has a realistic chance of working. It makes less sense once the cancer has stopped responding.

Which of these suit your cat, and at what dose, is for the vet to decide. Never give a cat a human painkiller or stomach remedy. Ibuprofen, naproxen, acetaminophen and aspirin can seriously harm or kill cats.

Two questions are worth asking directly. Is there anything we have not tried that could make her feel better? And if we try it, how soon would we know whether it has worked?

Older cats with kidney disease as well

Many cats with lymphoma are seniors, and many senior cats also have chronic kidney disease. The two overlap. Both cause nausea, poor appetite and weight loss, so it can be hard to tell which one is behind a bad week. Blood and urine tests help the vet sort that out.

Kidney function also affects which medicines and fluids are safe for your cat. Steroids can raise blood sugar and bring on diabetes in some cats, so tell your vet if your cat starts drinking or urinating much more.

For the decision itself, it does not matter which disease is causing the bad days. A day spent nauseated and hiding counts the same way. Our article on when to euthanize a cat with kidney disease covers the kidney side.

A good-days and bad-days method

1. Write down what a good day is for your cat. For example: eats without coaxing, comes to find you, uses the litter box, grooms, sleeps in the usual spot.
2. Each evening, mark the calendar as good or bad.
3. List three to five things your cat has always loved, and note when each one stops.
4. Weigh your cat on the same scale each week and write it down.
5. When bad days outnumber good ones, or several come in a row, call your vet for an appointment to talk it through.

With large-cell lymphoma, start this on the day of diagnosis, because the change can come fast. It also helps to agree on a line with your vet in advance, such as two days without eating in spite of medicine. The quality of life scale for senior cats gives you a fuller score to bring to that conversation.

Planning the appointment

Choosing a day while your cat can still enjoy a little food and your company is not giving up. It spares the cat a final crisis. Some vets will come to the house, and what happens during pet euthanasia explains each step.

Euthanasia is only ever performed by a veterinarian. Never attempt it yourself; our article on whether you can put a cat to sleep yourself explains why, and what to do if cost or travel is the obstacle.

Call the vet today if

Call your vet or an emergency clinic now if your cat:

• Is breathing with its mouth open, or breathing fast or with effort while resting.
• Has not eaten for a full day or more.
• Is vomiting repeatedly, or cannot keep water down.
• Is on chemotherapy and becomes dull, feverish or stops eating. This can point to an infection that needs treatment straight away.
• Has pale, bluish or yellow gums.
• Collapses, cannot stand, or has a seizure.
• Cries out, or cries when its belly is touched.
• Is straining to urinate or pass stool.

This article is general educational information, not veterinary advice. Lymphoma behaves very differently from one cat to the next, and the survival ranges here are commonly reported figures, not a prediction for your cat. Decisions about treatment and about the timing of euthanasia should be made with your veterinarian or veterinary oncologist.