Vet Blog
11/01/09
 Hello, Dr. Barchas!
I wrote to you about a year ago about my kitty that was born with an overbite and asked how common were there etc etc…well, since then she has gotten a bit worse unfortunately. The vet said a tumor has infected her poor deformed jaw and could slowly suffocate her to death because it’s pressing on her throat and eye. We are currently treating her with cortisone and Antirobe, which we see a small change but these medicines never seem to last long enough because abscesses keep coming back. My question is there any hope of this turning a tumor around? Does this seem like the only thing that could be done or used to treat this infection/tumor in the bone? Is there body that could help us on the cost of further treatments? She’s only 2 years old and too beautiful to let go…I would appreciate any help or advice.
Thank you!
shannon
Middletown, Ohio
Overbites are very common in cats. Usually they are harmless. Cats are lucky to be less superficial than humans–cosmetic trivialities like overbites don’t lead to social ostracism or low self esteem.
Severe overbites can be more than a cosmetic problem. In some cases the teeth of the lower jaw can grow into the tissue of the upper jaw. This can lead to painful infections or areas of chronic inflammation (irritation).
The areas of chronic inflammation can look just like tumors. True tumors are extremely rare in the mouths of two-year-old cats.
I therefore wonder whether your cat actually has a tumor. It sounds more likely that a wayward tooth is causing chronic inflammation that looks like a tumor. I suspect that dental work (specifically, extraction of teeth that are growing improperly) might remove the source of inflammation and solve the problem permanently.
I agree that it is too soon to give up on your cat. Some local SPCAs have veterinary hospitals that offer discounted services to needy individuals. If such a facility is available in your area perhaps your cat can benefit from a procedure that will allow her to live a normal life.
Photo: no sign of an overbite on Ben.
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10/01/09
 Hi Dr. Barchas,
Do you have any experience with cats who have been exposed to methamphetamine vapors? We lost our 4 year old cat to lymphoma and I am feeling like the worst cat parent ever…it’s no longer an issue, and we are having our 10 year old Maine Coon thoroughly checked out, and have been totally honest with our vet. Bottom line: is this my fault? and what kinds of long term symptoms might we watch for in our Maine Coon?
Name and location withheld
I may have bitten off more than I could chew when I decided to discuss canine marijuana ingestion twice (here and here; you can also check out my website for more information on the subject here) on this blog.
Yesterday I spoke on the phone with a person who tracked me down on the internet. She was interested in using medical marijuana to help with lack of appetite in a dog who was undergoing chemotherapy. The dog had been to a number of specialists and clearly had received the best possible medical and home care. The client was exploring every possible option to promote a high quality of life for the pet. (My answer, in short, was that evidence-based studies on the subject were lacking. However, if adverse side effects could be avoided, the therapy might be beneficial. The legal ramifications of such therapy are uncertain but possibly (although probably not) serious depending upon the jurisdiction. The client elected to experiment cautiously.)
On the same day, I read the question posted above.
I am not a specialist in animal toxicology. This blog is not a clearinghouse for questions about pets and illicit substances.
Nonetheless I feel that rushing to judgment is not in the best interest of the animals involved in these sorts of situations. What follows is my best attempt at an answer. To the questioner:
Methamphetamine vapors almost certainly are harmful to cats. Cats’ lungs are exquisitely sensitive. Second-hand cigarette smoke can trigger or exacerbate a number of feline respiratory problems. Although methamphetamine vapors contain less tar than cigarette smoke, it is hard to imagine that second-hand meth is not deleterious.
That said, it also is hard to imagine that your cat’s lymphoma was caused by exposure to methamphetamine. Meth has numerous adverse effects on the body. It may well be a carcinogen in cats–this matter has not been well studied. But the carcinogenic effects of any substance of are dose-dependent. Second-hand exposure to methamphetamine vapors will not lead to high levels of exposure.
Bottom line: I doubt that methamphetamine exposure played a role in your cat’s illness. It is more likely that a hereditary predisposition to lymphoma was to blame.
I recommend that you monitor your Main Coon’s appetite, thirst and weight. Seek veterinary attention if you note any irregularities. I consider it unlikely that he or she will experience adverse effects from exposure to the illicit substance.
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08/24/09
 My dog is about eight years old and his throat area is enlarged, like really big. It doesn’t really feel like a lump it feels more like his actual throat is swollen. Could it be his thyroid?
Tracie
Orangevale, CA
There are many things that can cause the throat of a dog to swell. All of them require prompt veterinary attention. Swelling in the area of the throat can compromise swallowing and breathing with disastrous results.
Allergic reactions to insect bites or vaccines may cause sudden swelling of the throat. Untreated allergic reactions can progress to shock, suffocation, and death.
Trauma to the throat can cause swelling. Sudden jerks to the collar or other blunt forms of trauma may lead to the symptoms you describe. Penetrating trauma can occur when dogs impale themselves or chew on sharp objects, leading to swelling in the affected area.
Infections in the throat may lead to swelling. Wounds from fights may cause abscesses (severely swollen infected areas). Foreign objects such as foxtails can lodge underneath the skin or in the trachea or esophagus, leading to infected, swollen areas.
Problems with salivary glands sometime lead to throat swelling.
Unfortunately, cancer is a common cause of swollen throats in older cats and dogs. Lymph nodes in the throat may be infiltrated with cancer, causing them to enlarge.
Thyroid disease is common in eight-year-old dogs. However, it does not lead to swelling of the throat.
Your dog should go to the vet. Hopefully the problem is not serious.
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07/02/09
 Hi Dr. Barchas,
I know that the feline rabies vaccine has been associated with fibrosarcomas at the site of injection. Is it possible for the vaccine to cause tumors in other locations? Someone told me that the three-year rabies vaccine was more likely to cause cancer – is this true?
My cats received the three-year vaccine several years ago. One of them developed an aggressive tumor in her abdomen a couple years later. As surgery would not improve her quality of health, we elected to put her to sleep. Although a couple of years have passed, I remain worried about my other cat (her sister) and if my choice to have them vaccinated with the three-year shot contributed to my beloved cat’s death. Thank you for any insight.
Tera
Columbus, OH
You have asked some very good questions. I’ll do my best to answer each of them.
Vaccine-associated fibrosarcomas are cancers that develop rarely at the site of rabies or feline leukemia vaccines. They appear to occur only in cats. The cause of the tumors is very poorly understood.
The cancers develop at the site of injection. I have not seen any reports of vaccines causing tumors in distant locations. Therefore, it is extremely unlikely that your cat’s abdominal tumor was linked to a vaccine. Fibrosarcomas can develop naturally, and if your cat suffered from a fibrosarcoma in her abdomen it likely occurred spontaneously. I sincerely doubt that your decision to vaccinate your cat contributed to her death.
Three-year rabies vaccines usually contain a component called adjuvant that is designed to help stimulate the immune system. One-year vaccines generally do not contain this component. Some people have hypothesized that adjuvant contributes to fibrosaroma development. These people therefore speculate that the one-year vaccine may be less likely to cause cancer than the three-year vaccine. I have not seen conclusive proof of this.
For instance, some studies have suggested that merely inserting a needle into the skin may trigger a cascade of inflammation that ultimately leads to cancer. This implies that the adjuvant is not to blame.
Also, remember that one-year vaccines must be given three times as often as three-year vaccines. The relevant question therefore is whether one-year vaccines are three times less likely to lead to cancer.
A few years ago I attended a lecture by a representative of a company that produces one-year, non-adjuvanted feline rabies vaccines. After the lecture I cornered her (literally–she was trying to get away and I backed her into a corner) and asked the following question. I remember it verbatim.
Can you provide quantitative evidence that three-year vaccines are three times more likely to cause cancer as your one-year, non-adjuvanted vaccine?
Her answer was no. To this day I have not seen any study that proves that three one-year vaccines are safer than one three-year vaccine (if anyone is aware of such a study, please let me know).
It is unlikely that your remaining cat will develop a fibrosarcoma from her rabies vaccine. Fibrosarcomas develop in approximately one out of every 3000 – 10,000 cats that receive the vaccine. I have no reason to believe that your cat is at increased risk.
Although vaccine-associated fibrosarcomas are not common, I still recommend that you never accept a one-size-fits-all vaccination plan for your pet. Good vets always are willing to talk about the risks and benefits of vaccination. Make an informed decision.
Photo: Myriah after removal of a vaccine-associated fibrosarcoma.
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06/01/09
 I always am saddened when I diagnose cancer in a patient. However, the remorse I feel when making the diagnosis generally has been tempered by a small silver lining. Most of the cancer patients I treat do not seem to realize that they are sick. Although humans with cancer often suffer profound psychological effects from the diagnosis, most pets behave as if they feel fine until the disease causes serious complications.
Or so I had thought.
A brief article in the June 5, 2009 issue of The Week has given me a reason to look harder at the quality of life of my cancer patients. It also has given me another reason to hate cancer–as if I needed one.
Tumors are doubly depressing
A diagnosis of cancer is obviously a good reason to be depressed. But new research finds that the feeling isn’t just psychological: Tumors produce high levels of a chemical that can effect [sic] mood and make people feel down. Behavioral neuroscientists at the University of Chicago compared depression and anxiety rates in groups of rats with and without tumors. Since rats have no awareness that they have cancer, Dr. Brian Pendergast tells BBCnews.com, “their behavioral changes were likely the result of purely biological factors.” He found that rats with cancer exhibited signs of depression and anxiety, floating passively when placed in water while cancer-free rats swam for safety. The tumor-ridden rats also hoarded and buried objects they were given, and lost interest in eating sweets. The scientists believe that the anxious and depressive behavior is connected to levels of chemicals called cytokines, which are produced by tumors and also by the immune system when it’s battling cancer. Rats with tumors had double the normal level of cytokines, which have a direct, depressing effect on emotional centers in the brain.
Note that this study does not say anything specifically about dogs or cats. But it does give me an additional reason to hope that some major breakthroughs in cancer research will come soon. For the record, I think they will.
Also, be aware that a great deal of research currently is directed towards understanding and modifying cytokines (cytokines are linked to pain and a number of other physiological responses that might be modifiable through pharmaceuticals). However, in the case of cancer, there is no doubt that the best approach is not to target cytokines. The best tactic is to cure the disease.
Photo: Transposagenbio. License: CC.
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05/28/09
 My 13 year old dog has stopped eating everything. She will drink water but no food. It has been a few days now. I looked into her mouth and one tooth is sort of black and so is the gum. She throws up about once a day also. Could all this be from her tooth?
Shirley
Jacksonville, FL
Animals do not stop eating unless there is a reason.
When I think back to the last time I went a day without eating despite food being available, I remember being very sick. Similarly, when a pet stops eating it means that something is wrong.
Dental disease causes or has been linked to a huge number of problems in cats and dogs. However, unless a tooth has abscessed acutely, dental problems rarely cause pets to stop eating completely. I therefore consider it unlikely that your dog’s tooth is the cause of your dog’s inappetance.
I am worried that a metabolic problem such as liver disease or kidney disease, or a glandular disorder such as advanced diabetes, or cancer may be causing your dog’s appetite to disappear. Many other problems, such as infections with viruses or bacteria, trauma or dehydration also may cause symptoms like those you describe.
I recommend immediate veterinary attention for any pet that goes more than one day without eating. The sooner you find out what is wrong, the higher your chances of successfully addressing the problem.
Photo: this is what we want to see!
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05/09/09
The April 25, 2009 Economist’s science and technology section contained an article that discussed a promising technique to aid in treating cancers in all species.
A DIAGNOSIS of cancer is often followed by a prescription of surgery. Before chemotherapy, before radiation, the knife is frequently the oncologist’s first line of attack. If done early and well, it has the potential to stop the disease in its tracks. Even if it does not, it is the best way for the doctor to get a feel for what he is dealing with, how extensive it is, and what to do next. But, whereas therapies and diagnostics for cancer have been evolving steadily in response to new biochemical knowledge, surgical techniques have remained surprisingly primitive.
What happens at the moment is that a surgeon roots around inside a patient, removes as much tumour as he can find, and hopes he got it all. He then sends what he has excised to a laboratory, where pathologists sample all around the outside of the extracted mass to see if it is encapsulated by healthy tissue. If it is, the whole tumour has probably been removed. If not, the surgeon must go back in, and the time-consuming process starts again.
Roger Tsien and his colleagues at the University of California, San Diego (UCSD), are trying to halt this cycle by creating a luminous map for the surgeon to follow. Dr Tsien, who shared the 2008 Nobel prize in chemistry for his work on green fluorescent protein, has found a way to make cancer cells glow. That could help surgeons see precisely what to cut out and what to leave behind.
Tumor removal surgery definitely can be harrowing business. The mainstay of tumor excision is obtaining “wide margins”. This means that the capsule of healthy tissue surrounding the tumor should be as large as possible. But tumor tissue can only be definitively diffentiated from normal tissue when it is examined under a microscope.
The technique detailed in the Economist will do nothing to address the need for microscopic evaluation to definitively determine tumor margins. However, it definitely is a step in the right direction.
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05/03/09
 Love to read your Q&A. I have a two-year-old Pekinese.
She has not been spayed. No pups. Should I have
her spayed? Thanks Ursula.
Ursula
Cape Town, South Africa
Until recently it was an article of faith among veterinarians that spaying and neutering dogs and cats is always in their best interest. That faith has been shaken somewhat in recent years, but it is my opinion that the benefits of spaying your dog likely will outweigh the possible negative factors.
Spaying your dog will eliminate her risk of pregnancy, uterine cancer, and ovarian cancer. She will be less likely to get lost or be struck by a vehicle while seeking trysts. She will be less likely to be injured in fights or while mating. Spaying your dog will prevent her from contracting sexually transmitted diseases (it’s true–dogs can catch VD!). She will be less likely to suffer from a common and deadly infection of the uterus (or remnants of the uterus) called pyometra.
Dogs that are spayed before their first heat cycle have their risk of breast cancer reduced by nearly 100%. It is too late for your dog to reap this benefit, but it is an important piece of information.
Be aware that spaying is not completely risk free. Spayed dogs may be at higher risk of obesity and urinary incontinence. Some studies have linked surgical sterilization to increased rates of knee injuries (although not in Pekingese) and certain types of cancer. The surgery itself carries a very slight risk of complications.
Like so many things in life, the benefits of spaying your dog must be weighed against the risks. In my experience, the benefits of the procedure decisively outweigh the risks for the vast majority of dogs. I suspect that yours is among them. If you’re not planning on breeding her, then I would recommend that you have her spayed.
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04/24/09
 I have long maintained that pets are good for people. Scientific studies back this up. They help to lower our blood pressure, decrease our rates of diabetes, and help us to get more exercise. They inspire sick people to become well, and they help to prevent and treat depression.
Human medical advances historically have been the basis of veterinary medical advances. New human treatments are often adapted to animals.
But a report in Science Daily shows that sometimes it can be the other way around.
The story describes a new treatment for a serious form of canine cancer: anal sac adenocarcinoma. Anal sac adeoncarcinomas are aggressive tumors with limited treatment options. Or rather, the options used to be limited.
A new treatment has been developed. It relies on the fact that tumor cells have extra receptors for vitamin B12. In the treatment a relatively benign molecule, nitric oxide, is attached to vitamin B12. The nitric oxide is toxic to cancer cells. It has little impact on the rest of the body.
Since humans don’t have anal sac glands (and therefore we don’t suffer from anal sac adenocarcinomas), it may seem that this treatment wouldn’t be of much interest to the field of human medicine. However, our tumors often have extra vitamin B12 receptors. This means that, with some gentle manipulation, the therapy may some day be useful to us as well.
It’s a win-win situation, to be sure.
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03/01/09
 In 1991 veterinary medicine suffered a disturbing revelation. Two commonly used feline vaccines were linked to the development of malignant tumors at the site of vaccination. The tumors, called fibrosarcomas, are associated with the vaccines for rabies (in cats only) and feline leukemia. They are aggressive and difficult to remove. They occur in approximately one out of every 3000 – 10,000 cats who receives a rabies or leukemia vaccine.
The discovery of these so-called vaccine associated fibrosarcomas lead to the creation of a special task force (called, unsurprisingly, the Vaccine Associated Fibrosarcoma Task Force). The recommendations of the task force were supposed to cause a dramatic shift in the way cats are vaccinated.
Prior to the discovery of the fibrosarcomas and the formation of the task force, most cats were vaccinated against rabies and leukemia every year. The vaccines were administered between the shoulder blades because that is the easiest place to give injections to cats.
The task force recommended that the leukemia vaccine should be administered only to cats who spend time outdoors. The rabies vaccine should be administered as required by law. If possible, both vaccines should be administered no more frequently than once every three years.
Finally, the task force advised veterinarians to change injection sites. Fibrosarcomas between the shoulders are virtually impossible to remove. Therefore, the leukemia vaccine should be administered in the left rear leg, near the ankle. The rabies vaccine should be administered similarly in the right rear leg. If a fibrosarcoma develops in either of these locations, the cat’s life can be saved by amputating the leg–a less than perfect solution to the problem, but better than the alternative.
Vaccine associated fibrosarcomas are a source of angst for me. I have worked during my career to minimize the number of rabies and leukemia vaccines I give to cats. And I always give the vaccines in the rear legs.
However, a very disturbing paper published in the February 1, 2009 Journal of the American Veterinary Medical Association (JAVMA) indicates that many veterinarians are ignoring the recommendations of the task force and needlessly endangering the lives of their feline patients. According to the paper, significant numbers of cats are developing vaccine associated fibrosarcomas between their shoulder blades. This means that significant numbers of veterinarians are still giving rabies and leukemia vaccines in that spot.
Here are the conclusions of the paper.
Conclusions and Clinical Relevance–Despite publication of the vaccination recommendations, a high proportion of tumors still developed in the [region between the shoulder blades] . . . [v]eterinarians are complying with vaccination recommendations to some extent, but need to focus on administering vaccines as [far down] as possible on a limb to allow for compete surgical margins if amputation of a limb is required. (J Am Vet Med Assoc 2009;234:376-380)
What can you do to ensure that your vet is following the task force’s recommendations? Talk to him or her. Ask whether vaccination for leukemia and rabies is appropriate for your cat. If the vaccines are appropriate, ask where they will be administered. Never accept a one-size-fits-all approach to vaccination.
Photo: A vaccine associated fibrosarcoma between the shoulder blades of a cat, courtesy of Texas A&M’s School of Veterinary Medicine.
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Hello, Dr. Barchas!
You have questions. 