Radiotherapy in Cats

Radiotherapy in Cats - Conditions Treated, Procedure, Efficacy, Recovery, Cost, Considerations, Prevention

What is Radiotherapy?

Radiotherapy is a means of treating certain cancers in the cat. The aim is to damage and kill the cancer cells that make up a tumor, while preserving healthy tissue. Not all cancers are amenable to radiotherapy because of their type or location. Indeed, not all patients are candidates for radiotherapy since each treatment requires a full general anesthetic. 

In addition, there are relatively few specialist centers with the necessary equipment and expertise to offer radiotherapy, which can mean a considerable journey in order to reach an appropriate specialist. This may mean it's not practical to undertake a course of radiotherapy since regular weekly visits are usually required. 

Radiotherapy Procedure in Cats

The patient is carefully screened for suitability to undergo the repeated anesthetics necessary for radiation treatment. Protocols differ but the cat may need repeat sessions on a weekly basis for several weeks, or therapy on alternate days. For the latter it may be best for the cat to be hospitalized for the duration of treatment in order to avoid the rigors of travel. 

It is crucial the cat stays absolutely still during treatment, as movement could lead to irradiation and damage to healthy tissue. The cat will be anesthetized and monitored remotely using equipment that reads out in the adjacent viewing room. 

The first session likely involves a fresh CT scan (even if the cat has had a previous scan as part of the diagnostic work up) so that the exact tumor margins can be assessed and the radiotherapy beam focussed in exactly the correct place. 

Fur will the shaved and the skin marked up with a permanent marker to facilitate positioning of the radiation beam. The duration of each exposure will depend on the type, size, and location of the tumor. 

After each irradiation, the patient wakes up and is allowed home, usually the same day (for those not boarding at the hospital).

Efficacy of Radiotherapy in Cats

Radiotherapy is rarely the first option for treating a tumor. Where, possible complete surgical removal  or chemotherapy is prefered. However, for tumors that are not suitable for surgery, radiotherapy offers a highly effective, and life-extending treatment. 

Radiotherapy is not used in the same way in cats as in people. In the latter, much higher doses of radiation are used with the aim of curing in the patient. However, much lower doses are used in cats, with the aim of extending good quality life (rather than a cure) with a minimal amount of distress to the patient.

Radiotherapy is very good at what it does, which is: 

  • Destroying tumors at inaccessible sites
  • Shrinking down tumor size
  • Pain relief
  • Part of a wider spectrum of treatments which may include chemotherapy or surgery

Radiotherapy Recovery in Cats

Lower doses of radiation are used in cats, which means less discomfort post-treatment. Once awake from the anesthetic the cat may experience a short period of discomfort but this soon passes. Indeed, radiation is sometimes used for pain relief as it also damages the nerve supply to the tumor. 

In the longer term, the fur in the irradiated area may grow back white. Also, the irradiated skin may be lesion resilient in the future and more prone to infection or damage, but this is easily managed with appropriate antibiotic cover. 

Cost of Radiotherapy in Cats

Not only is the actual procedure expensive but there will be associated costs such as for travel and accommodation for those who live some distance from the referral center. 

A consultation with a veterinary oncologist can be around $250 - $300. A repeat CT scan is needed, at around $630 - $2,000. The cost of a remotely monitored anesthetic will vary according to the length of each treatment. The most sophisticated anesthetic agents are used, and typically anesthesia comes in at $140 or more. Finally, comes the cost of the actual radiation treatment itself. The cost will vary widely depending on whether the aim is to kill the cancer or provide palliative care, but is likely to be thousands of dollars. 

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Cat Radiotherapy Considerations

Radiotherapy is a relatively new science for the treatment of cats. It offers the potential to extend life in what might otherwise be hopeless cases, but unfortunately the therapy is costly and not widely available. 

Before you commit to a course of radiotherapy it is important to weigh up the character of your cat and how they will cope with travel and repeated anesthetics. For example, if they hate travelling and spend the next two months making long journeys on a weekly basis, and radiotherapy only extends life by four months, then you have to weigh up if this is truly beneficial to the cat or not. 

Radiotherapy Prevention in Cats

Radiotherapy is often used when surgery is not an option. By being vigilant and checking your cat weekly for lumps, you are more likely to detect tumors at a stage when they are still amenable to surgical removal. 

Most cancers in cats occur spontaneously, and so prevention of cancer is a goal yet to be achieved. 

Radiotherapy Questions and Advice from Veterinary Professionals





Fifteen Years


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My pet has the following symptoms:
My cat had to go to ER on 1/2/21 after showing some disoriented behaviors including vomiting, mouth breathing and faint. ER doctor thinks she has a brain tumor. It looks like she even lost her visions too. She was also diagnosed CKD on last October. After giving her prednisolone she is doing well and only showing minimal abnormal behaviors. Considering her age and personality ( she is very sensitive). I'm not sure what will be best for her. Of course I want to give her more long good quality of life. But I'm not sure if giving her Radiation Therapy will be worth for her at this point.

Jan. 21, 2021

Answered by Dr. Maureen M. DVM

0 Recommendations

Hi, Sorry for what you are going through. Cancer can be a tough condition to deal with. As long as the tumor has not spread to critical organs such as the lungs I think it is worthwhile to take a shot. After the first cycles, you can review with your vet your cat's progress. If there is no change or if his condition worsens then it would be a good time to review other options in a bid not to put your cat through more pain and suffering. Good luck.

Jan. 21, 2021

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short hair




11 Years


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1 found this helpful

My pet has the following symptoms:
Vommiting No Appetite
Since my cat has had radiotherapy for a nasal tumour he has stopped eating and drinking ( we feed and hydrate him with a syringe ) we were told that apart from sores , ( which we were given cream for ) he wouldn’t experience any other side effects. After we feed him he will hide so he is obviously experiencing discomfort after he eats and he vomits often after he eats. He is also hunched over slightly. He did have some constipation which we have treated and we thought that the problem would be resolved but it has not. He has had chemotherapy before the radio therapy but after the rumour in his lymph node returned we opted for radiotherapy as we were told he wouldn’t experience side effects other than blistering. He has lost weight and is slightly unsteady on his feet at times ( not often ) he has had blood tests which have come back normal. No obvious signs of cancer returning. Constipation seems resolved. He has the want to eat but we think he can’t smell which stops him committing to eating , that and him feeling unwell after he eats. When we feed him with a syringe he eats but not with any great commitment. Could he have ulcers as a result of prednisone? he is 11 years old

July 29, 2018

1 Recommendations

Radiotherapy is generally minimal with side effects compared with chemotherapy or other treatments; however there are many causes for a lack of appetite and thirst which may include pain, enlarged lymph node in the throat, nausea, medication side effects (prednisolone normally causes an increase in thirst and appetite) among many other conditions. Corticosteroids are associated with gastrointestinal ulceration in literature but is generally uncommon. Without examining Indi I cannot pinpoint a specific cause for the symptoms but you should return to your Veterinarian to determine the cause and monitor. Regards Dr Callum Turner DVM

July 30, 2018

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