Cat Cancer Study Sheds Light on Human Cancer

Cancer is the leading cause of death in cats, according to the Pet Cancer Center. Among humans, cancer remains a primary cause of death around the globe, the World Health Organization reports, with up to 84 million people projected to die of cancer by the year 2015.

Such statistics are daunting. But for reasons not yet fully understood, cat cancers tend to be among the most aggressive among mammals. It’s possible that we’re just not detecting them early enough. Researchers, however, are learning more about cancer, with treatments improving with advanced science, knowledge and technology. Kim Selting, an associate teaching professor of oncology at the University of Missouri-Columbia College of Veterinary Medicine, shares some of her latest findings, which could also apply to our health.

The Mammal Cancer Connection

Researchers, like Selting, are working to establish connections that can benefit all mammals suffering from cancer. “Recent initiatives in medicine emphasize the fact that despite differences in anatomy, the basic parts are the same across species, especially mammals,” she explains. “And despite minor differences in physiology, those parts have very similar functions and responses to disease across species.”

As a result, her university has created the One Health, One Medicine initiative. It emphasizes research on numerous animals -- not just rodents, which used to be the norm for cancer studies. Selting recently coauthored such a study, published in the Journal of the American Animal Hospital Association. In it, she suggests that the following five factors can apply to cancer in cats, dogs and humans:

1. Genes Selting explains that “breed affects cancer risk just as race/ethnic origin can do so in human medicine.” This is because the genes among individuals in certain pet breeds, or human populations, are likely to be similar. “If said genes, such as tumor suppressor genes, are faulty and are related to the risk of acquiring a certain cancer, then it follows that these cancers will be overrepresented in a given population.” Siamese cats, for example, can be predisposed to intestinal and breast cancers.

2. Environment Selting suggests that cats that breathe tobacco smoke, for example, may have a heightened risk for lung diseases. “Cats are fastidious groomers, and every environmental contaminant that is present in the air and settles on the fur is then exposed to the cat’s mouth and system as they lick their fur.”

3. Diet Food may also contribute to disease prevention or instigation. “Feeding a good-quality diet logically can improve health, though no particular diet is known to abrogate cancer,” says Selting.

4. Lifestyle Countless studies conclude that exercise and stress levels can impact cancer.

5. Medical Care No tests can currently predict cancer occurrence in cats, but “early detection often offers a better prognosis,” says Selting. “Any change in a cat’s health should be investigated.”

Cancer Prevention for Cats and Humans

While much about cancer still remains a mystery, the new studies at least suggest a course of preventative action.

  • Pay attention to genes. Consult with your doctor and your cat’s veterinarian and discuss the risk factors related to your ethnic origin and your cat’s breed.
  • Do not smoke, and keep your home clean and free of potentially dangerous chemicals.
  • Follow the latest research concerning food and cancer prevention.
  • Both you and your pet need to exercise. Our bodies evolved to handle ample activity, so talk with your doctor and your cat’s veterinarian about what exercise would be best.
  • Note physical changes in both you and your cat. Schedule regular medical appointments, which can detect cancer before symptoms even surface.

While Selting and others prove that studying cancer in cats can shed light on human cancer, researchers are also driven to learn more about cats. “Companion animals rely on humans for food and shelter, but they repay the favor with devotion and companionship. We are their voice and are responsible for their quality of life,” says Selting.

Cat ‘Breast Cancer’: Mammary Disease

Dr. Trisha Joyce, a veterinarian for New York City Veterinary Specialists, knows how lethal mammary disease -- cancer of the mammary glands -- can be in cats. The first case of mammary cancer she saw was with a cat that was brought in with a lump. “We removed the tumor and the cat was fine. Six months later, the couple and the cat were back. Another tumor had appeared. This one had ulcerated, and it was too late to treat it.”

Since that time, Joyce has counseled cat owners on how to prevent and detect mammary disease, and how to proceed once it’s been diagnosed. Below, she shares her advice on each of these.

Risk Factors
Mammary cancer is the third most common cancer among cats, and it is also one of the most preventable. “First and foremost, spay your cat,” says Joyce. Kittens spayed before they are 6 months old have a 91-percent reduction in their risk of developing the disease. Kittens spayed before they are 1 year old have an 86-percent risk reduction. In contrast, cats spayed before the age of 2 have only an 11-percent reduction, with no reduction of risk at all after age 2.

Mammary tumors are most commonly found in unspayed cats between 10 and 12 years old. Siamese cats are more likely to develop the disease, and the onset is typically earlier. Male cats very rarely develop mammary cancer, although it can happen -- and is usually aggressive when it does.

Detection
When Joyce meets owners of unspayed cats, she encourages them to perform regular mammary exams at home. The idea is similar to the self-exams that women are taught to perform by their gynecologists in order to become familiar with their own breast tissue. “If you know how your cat’s mammary glands feel when they’re free of tumors, it’s easier to catch a growth if one develops,” she says. The tumors are not painful to the touch, though cats that don’t like to be stroked may try to get away.

To examine your fluffy friend, run your hand over the fatty tissue around her nipple. “Just rubbing the belly is too superficial. Squeeze the tissue a little, almost like milking a cow. You’re looking for a lump like a little hard pea, or sometimes bigger,” says Joyce. Finding a lump is a good reason to visit the veterinarian as soon as possible: Doctors estimate that as many as 90 percent of mammary tumors in cats are malignant.

Other than these telltale lumps, mammary cancer is asymptomatic in its early stages. If it metastasizes, the cat may go on to develop health problems related to where the cancer has spread.

Diagnosis and Prognosis
Because feline mammary tumors are so likely to be malignant, prompt removal of the entire mammary chain on the effected side is most veterinarians’ treatment of choice. Mammary surgery is less complicated than mastectomy in women, as a cat’s breast tissue is outside of the muscle layer. Prognosis is best the earlier the cancer is caught, and the smaller the tumor is. Surgery yields a disease-free year for 50 percent of cats, while almost one-third of cats will go two years without the development of additional tumors. Surgery is often followed by a course of chemotherapy.

In advanced cancers that have metastasized, surgery may still be performed to reduce the impact of the tumor and improve quality of life. Sometimes, though, a metastasized mammary tumor means it’s time to let your cat go. “The tumors can become ulcerative, making just moving around extremely uncomfortable, or if they spread to the lungs or the bones and make breathing or walking very hard, the most humane option may be euthanizing,” says Joyce.

Mammary cancer in felines is fairly common, but it is also preventable, and most often not immediately fatal. With early detection, surgery and chemotherapy, your cat may have additional good years to spend with her loved ones.

Coping With the Loss of a Cat

Dealing with the death of a cat is difficult for any owner -- no matter the age of your pet.

Dr. Trisha Joyce of New York City Veterinary Specialists, and Dr. Wallace Sife, a clinical psychologist and founder of the Association for Pet Loss and Bereavement (APLB), offer advice on managing the end, grieving and moving on.

End-of-life Decision-making
While a small percentage of cats may die peacefully at home from old age, most pet owners will at some point be faced with the decision to end their cat’s suffering. “Sometimes it’s an uncomplicated decision -- say an animal stops making red blood cells,” says Joyce. “But just as often it’s a slow process, like gradual kidney disease. The cat still has a good day every once in a while.” In the latter situation, Joyce recommends the following:

·         Make a list of the things your cat enjoys, like sunbathing or spending relaxed time with the family. Consider whether it still engages in any of these.

·         Give yourself an objective measure -- a point at which you will let the pet go. For example, “Once my cat’s weight has dropped to X number of pounds, I will put him down.”

·         Seek guidance from your veterinarian and other pet owners who have had to make a similar difficult decision. The APLB’s website offers chat rooms addressing the topic.

“Owners will say to me ‘I can’t kill my cat,’ but that’s not what euthanizing is,” says Joyce. “I think of it as releasing the animal. It’s the last and most selfless decision we make for a pet we have cherished and cared for.”

Memorializing a Beloved Cat

Deciding how to mark a cat’s passing is a very personal decision. Some pet owners choose the formality of a proper funeral in a pet cemetery, and others cremate and scatter their pet’s ashes. Many veterinary hospitals offer to create a clay imprint of a cat’s paw as a keepsake.

Sife suggests making a contribution to an animal group in your pet’s name, planting a tree in its honor, volunteering with shelter animals or setting up a memorial on the APLB’s website. “We’ll light a candle for the cat each year on the anniversary of its death,” he says.

Coping in the Aftermath

Everyone deals with loss differently, although cat owners can expect to go through the same stages of grief as anyone who’s experienced the loss of a loved one. Sife suggests reading one of the many books on the topic, including his own, The Loss of a Pet. “The pain is unavoidable, but a book can help to normalize the experience,” he says.

Most important may simply be allowing yourself to grieve. “It can be hard because society doesn’t allow public grieving as much with pets. People feel less comfortable saying ‘I’m going to take a day off of work because I just put my cat to sleep,’ but it’s legitimate,” says Joyce. She adds that some of her clients have found support groups for people who find they need more comfort than they are getting from friends.

Adopting a New Companion

While a pet can never be replaced, at some point many cat lovers may want to bring home a new pet. Sife advises against seeking out a look-alike. “That may be a way of refusing to accept the loss,” he says. Joyce also advises waiting until the raw part has passed.

If you’re thinking about getting a new cat, consider adopting a stray cat from a local shelter. Saving the life of a cat without a home can be one more way to honor the memory of one that’s passed.

The Dangers and Risks for Outdoor Cats

The Humane Society of the United States supports indoor-only living for cats, but some owners remain convinced that life in the “great” outdoors can be beneficial. A new study on the secret lives of feral and free-roaming house cats solves the mystery. One message is clear: Living outdoors poses countless threats to cats. Here, learn why the life expectancy for outdoor cats is shortened by about 10 years versus that of indoor-only house cats.

Roaming Over Widespread Territories
Richard Warner, an emeritus professor of natural resources and environmental sciences at the University of Illinois at Urbana-Champaign, and his colleagues conducted the study, which was recently published in the Journal of Wildlife Management. Using radio transmitters and other high-tech equipment, the researchers tracked every move of 42 owned and unowned cats living at the southern edge of Champaign and Urbana, neighboring cities in Central Illinois.

As anticipated, feral cats had larger territories than the pet cats and were more active throughout the year. Even the researchers, however, were surprised by one mixed breed male, which had a home range of 1,351 acres, the largest tract of all cats tracked.

“That particular male cat was not getting food from humans, to my knowledge, but somehow it survived out there amidst coyotes and foxes,” says co-author Jeff Horn. “It crossed every street in the area where it was trapped. [It navigated] stoplights and parking lots.”

The average home range for pet cats was 4.9 acres, but as Horn says, “That’s a lot of backyards.” They ran, stalked prey, slept, rested and often encountered feral cats looking to establish dominance over an area. For example, each morning during the study, one feral cat waited for a particular pet feline to emerge in its garden. The feral animal would then attempt to chase away the house cat.

Dangerous Encounters
All outdoor cats can encounter various wildlife, in addition to the viruses and illnesses harbored by both feral cats and other species.

"For example, Toxoplasma gondii, a parasite spread primarily by cats, may cause neurological, reproductive and even respiratory problems in humans, cats and wildlife, depending on the species affected," says co-author Nohra Mateus-Pinilla of the Illinois Natural History Survey. “Rabies, cat scratch fever, feline leukemia and feline immunodeficiency virus are also of concern to pet owners whose cats encounter other cats outdoors. Vaccination of pet cats will reduce but not eliminate the threat of disease transmission.”

Warner agrees. “Two of the leading causes of cat deaths in that study were other cats and disease, and both of these leading causes of death are sitting here waiting for these owned cats outdoors.” This concern about disease doesn’t even take into account other threats, such as ingesting poisons, getting hit by a car, running into neighbors who hate cats and more.

The Solution
Adam Goldfarb, director of the Pets at Risk Program at the Humane Society of the United States, admits that in a perfect world, cats would be able enjoy the exercise, fresh air, sights, smells and sounds of the outdoors. The answers then are to help provide your cat with related experiences inside, or to fully control your pet’s time outdoors. Goldfarb suggests following these four steps:

  • If possible, train your cat to tolerate a leash. Your cat would still be exposed to germs, but at least many of the other dangers would be eliminated. Up-to-date vaccinations are critical.
  • Set up an indoor-outdoor enclosure where your pet is protected, such as by screens. Make sure proper shade and water are provided. Supervise your cat.
  • Cats love to climb, so establish vertical space for them in your home. You can get creative with cat trees, secure dedicated shelving or other cat-friendly items.
  • Most importantly, spend daily time interacting with your cats, whether that involves playing, training or just sitting on the couch with them.

Goldfarb urges owners not to buy into the stereotype that cats are somehow loners. They love receiving attention and hanging out with their owners. Just like a satisfied human mate, a healthy and content cat will easily let go of its roaming ways in exchange for a better, safer life indoors with you.

Allergic to Cats? New Vaccine Could Help

Did you know that 8 to 10 percent of the population is allergic to cats? If you’re one of those individuals, then the itching, watering eyes and sneezing associated with cats are all too familiar.

Now, a new vaccine holds promise of not just diminishing cat-allergy symptoms, but of curing the problem altogether. An added perk is that, unlike drugs that come with a laundry list of scary side effects, this vaccine has next to none, according to its creator Mark Larche and his team. Here, Larche, a professor at McMaster University’s School of Medicine, explains how the cutting-edge new vaccine could help you or your cat-allergic friends and relatives.

Cat Allergy Cause and Effect
It is a common myth that cat fur itself causes all of the sneezing and wheezing in those who suffer from pet allergies. What’s on the fur, however, turns out to be more important. “Allergies to cats are caused by proteins that are secreted by the cat and spread onto its fur by grooming,” says Larche. “Our vaccine is composed of synthetic fragments of one (the most important one) of these proteins.”

To identify the protein and to learn more about it, he and his team analyzed blood samples from 100 patient volunteers who are allergic to cats. Doing this allowed the scientists to see which components of the protein activate T-cells in certain people. T-cells are helper cells that fight infection in the immune system.

“Allergies are a form of hypersensitivity,” explains Larche. “We all make immune responses to allergens that we encounter in the environment, but most people make a tolerant response that results in no inflammation. However, for reasons that are incompletely understood, some people make the wrong kind of response -- an allergic response.” By providing low doses of the allergen -- tweaked so they don’t contain the parts that may stimulate the immune system -- the researchers came up with the new vaccine.

How Patients Receive Treatments

The vaccine is still only available in drug trials, but it appears that four to eight doses may be required in the first year, with possibly none required for subsequent years. Larche thinks a needle-less injection system could be used to administer the needed doses in the future.

Stephen Durham, head of the Allergy and Clinical Immunology department at Imperial College London, says the data about the new vaccine is very encouraging. “A significant proportion of cat owners develop allergy to their cats, which varies from bothersome eye and nasal symptoms through to moderate-severe disease or even life-threatening asthma attacks,” says Durham. “Avoidance strategies may be impossible or refused.”

Durham mentions that traditional allergy shots pose a risk of serious side effects, “particularly in asthmatics.” This new vaccine promises to provide “good symptom-control and disease remission, while avoiding the risk of side effects,” he adds. Cat-allergy sufferers both with and without asthma have participated in the trials, and so far so good.

Other Ways of Curbing Cat Allergies
Until the new vaccine becomes widely available, the Humane Society of the United States suggests that you try these five steps if your household includes one or more cat-allergy sufferers:

1. Clean your house often to remove dust and cat dander. Vacuum or wash curtains, furniture covers, pet beds and other items.

2. Bathe your pet often. Consult with your veterinarian to make sure that you are doing this correctly and using products that will not deplete your cat’s skin and fur of necessary oils.

3. Set up an allergy-free area. Close this area, such as the bedroom, off to your cat.

4. Consider purchasing a HEPA air cleaner, perhaps just for the allergic individual’s bedroom. Central heating and cooling systems can also be outfitted with stronger filtration systems to help clean the air.

5. Make sure it’s a cat allergy. Many things in the home can cause allergic reactions. Even people who are allergic to cats can be allergic to other things, so be sure the individual receives a thorough checkup from an appropriate specialist.

Some very good news is that the same research know-how that resulted in the new cat-allergy vaccine is being applied to allergies caused by dust mites, ragweed, grass, birch tree and moulds. In the future, most allergies may therefore figuratively bite the dust.