Mesothelioma in cats is extremely rare, and the authoritative sources I can find on the subject state that, comparatively, there is not all that much written about it. This disease is more common in dogs than cats, so most of the literature on pets that I found relates to dogs.
This form of cancer, at least in humans, is often linked to exposure to asbestos, and is relatively rare. This exposure to asbestos is said to usually have occurred 20, 30, or even 50 years prior to the development of the disease itself. Most of the time, the exposure occurred either in the work place, or in the home.
In addition, smoking is risk factor for human mesothelioma. Since pets don't smoke, this factor is eliminated in companion animals, especially if say a cat were to develop the cancer and no members of the household smoked (no risk of second hand smoke).
So the question is, how and why does a nine or 10 year old dog or cat get this illness? (Between five and nine years old is when a dog is at the greatest risk for canine mesothelioma. I have not found the corresponding data on cats).
Is it because pets are smaller creatures, with an accelerated life cycle compared to humans? If so, then when and where did the exposure to asbestos occur? Or, was it something else that caused it?
While it's been speculated that some cat litters may contain dust with asbestos particles in it, I have found no confirmation of supporting evidence. Generally, the consensus is that clumping clay litter, normally made from bentonite clay, is "safe."
If it is litter that's at fault, then it stands to reason that either it is not all litter, or that most cats are not affected in this way. Perhaps if cats lived to age 50, however, we may have different data. Also, unless affected dogs live with cats and are exposed to cat litter, that doesn't account for the disease in dogs.
Either way, this raises two points of concern. One, if it's non-litter related asbestos exposure at fault, then how did your cat get exposed? Did you or a family member bring it in the house?
For example, it might have been tracked in on shoes or some other article of clothing. If so, then you've been exposed as well. If that's the case, then owners of cats with mesothelioma may be at risk for developing the disease at some later stage.
Two, if it's litter related asbestos that is the cause of the illness, then both you and your cat are being exposed on a regular basis. This would mean changing the type of litter you use, since you can't really protect yourself or your cat.
The tumors produce fluid which builds up in the chest or abdomen. This can cause pain and swelling. Mesothelioma in cats can present as a peritoneal (abdominal) or thoracic (chest) problem. A classic cat illness symptom is a cat that appears thin except for a pot belly.
Initially, mesothelioma in cats may present as any other cancer. Significant weight loss in a relatively short period of time is a key sign that may indicate cancer in cats. It also may indicate other cat health problems as well. I don't need to tell you that if your cat seems to have a persistent or recurring cough, trouble breathing, or appears weak, these may also be signs of serious illness.
If you've worked with asbestos, be sure to mention this to your veterinarian so she can take that into account when determining what to look for and decide on relevant testing. Diagnosis depends on all relevant information, as a number of diseases may produce similar symptoms. Your vet will run preliminary tests typically starting with the general, and then getting more specific.
Unfortunately, the prognosis for mesothelioma in cats is poor, and the treatment is palliative, meaning that it focuses on treating the signs and symptoms. If you don't have a pet insurance plan, then any treatment for serious diseases such as cancer can be extremely expensive.
This often means that pet owners will euthanize their pets when a diagnosis is confirmed. Of course, this is also an option when the condition impacts quality of life.
In any case, treatment of mesothelioma rarely involves surgery, since it is usually not an option. As mentioned above, the clinical signs are often the presence of fluid in the abdomen or chest cavity. The tumor cells produce fluid that fills the body cavities, so treatment is focused on removing the fluid which is believed to provide for some relief.
Removal of the fluid build up can be done as needed (often weekly) in order to help reduce the effects of that build up. This is performed by physically using a needle to extract the fluid. Chemotherapy treatments are also done to reduce the effects of the fluid.
Dogs have often been treated with cisplatin by injecting the fluid right into the affected body cavity (intracavitary treatment). But cisplatin cannot be used on cats as it is lethal to felines. Fortunately, carboplatin is available for cats and, as this veterinary report shows:
"This is the first report of successful palliative chemotherapy for suspected feline mesothelioma and suggests that intracavitary carboplatin could be considered in tumours affecting the pleural cavity."
Unfortunately, this article goes on to say that the cat involved had to be euthanized after 120 days. Again, treatment for mesothelioma in cats is primarily about reducing the symptoms and making the patient as comfortable as possible.
If your cat has a serious illness, it's always best to seek advice from a qualified specialist. Work with your veterinarian to determine what is in the best interest of your cat.