Should a Pet With Cancer Get Chemotherapy?

by Michael Fagan, DVM

“Cancer” is a word that can induce fear and other emotions.  Many people have personal experiences with cancer and chemotherapy that they don’t wish to impose on their pets.  To be sure, cancer and the many treatment options we can offer are not to be taken lightly.  However, we do have many patients that have received treatments for cancer with favorable outcomes, from cures or long term remission to improved quality of life for many months to years.

The most important factor in determining treatment options and recommendations is what type of cancer the pet has developed.  “Cancer” is a very broad term, with many different types and variable response to different kinds of treatment.  Each patient with cancer is unique.  We offer options based on the type of cancer, symptoms or lack thereof, the pet’s overall health, and owner preferences.  Some cancers are best treated by surgical removal.  Others respond best with radiation, chemotherapy, or immunotherapy.  Some have a poor prognosis regardless of treatment, and control of pain or other symptoms takes priority before opting for euthanasia. We will often consult with a veterinary oncologist as we explore the options available.

The goals of treatment are also unique to each patient, but as a general rule, we aim for a cure only if we can preserve good quality of life throughout the process.  More often, we are trying for a long term remission or control of tumor growth for many months to a few years.  The most common treatment for cancers that are not curable with surgery is chemotherapy of one form or another.

Herein lies a vital difference between veterinary and human medicine:  in human medicine, the treatment goal is often to eliminate the cancer and then recover the patient; in veterinary medicine, we want to preserve good quality of life while limiting the cancer.  In other words, we use drugs, doses, and treatment schedules that minimize side effects while still providing the benefit of remission or delayed growth of the cancer cells. 

With chemotherapy, we have had lymphoma patients live longer than two years; bladder cancer patients, one to two years; dogs with nasal tumors, over a year; most with minimal side effects from the chemotherapy and reduction or elimination of symptoms caused by their cancer.  Unfortunately, not all patients respond, and not all tolerate the chemotherapy equally.  Each patient needs to have its treatment protocol customized. 

One relatively new approach to chemotherapy is using small daily doses instead of higher intermittent doses.  This tends to reduce toxicity and has a different effect on tumor growth.  Rather than actively killing tumor cells directly, low-dose daily therapy (called metronomic therapy) may work by reducing the blood supply to the tumor and by allowing the immune system to respond more aggressively. 

The bottom line is that we have many options for treating the many kinds of cancer that we diagnose in pets, including surgery, radiation (by referral to a veterinary oncologist), traditional or metronomic chemotherapy, immunotherapy (there is a vaccine for melanoma!), and/or palliative care (control of pain and other symptoms caused by the cancer). In animals we also have the option of euthanasia when appropriate but that is a subject for another blog. 

Cigarettes and Pets

by John Hallett, DVM

When I examine a dog or cat in our treatment room, away from the owner, I can almost always tell if the pet is from a smoking household. The smell of cigarettes lingers on their fur. That's not all that is lingering on their fur though. 

Most people understand that secondhand smoke from cigarettes contains an incredible number of hazardous substances and many of them can cause cancer. These chemicals are found in high concentrations on carpets and furniture around the home. Pets sharing this environment will get these toxins on their fur and then ingest them during normal grooming.

Cats may actually be at higher risk for serious disease when they live in a smoking environment.   Because of their fastidious grooming habits, cats end up ingesting a higher level of chemicals and this leads to a greater chance of several types of cancer.

Lymphoma is a cancer of white blood cells and is one of the most common cancers seen in our pet cats. When smokers are present in the cat’s household, the risk for this killer is increased by two or three times over cats living in non-smoking homes.  Sadly, when our feline friends are diagnosed with lymphoma, the prognosis can be poor.

Another serious cancer with links to secondhand smoke is a cancer of the mouth known as squamous cell carcinoma. Studies have linked a higher risk for squamous cell carcinoma in cats living in smoking homes. Again, the prognosis is very grave and most pets won’t survive another year.

Dogs are affected too.  In the early 1990s, researchers found correlations between nasal cancers in dogs and the presence of smokers in the home.  There is a concern that environmental tobacco smoke may increase the incidence of lung cancer in our canine friends as well.

Pets who are developing illnesses from secondhand smoke may exhibit symptoms ranging from lethargy to coughing to the appearance of masses in the mouth.  It’s important to have your pet seen by a veterinarian if any of these signs are noted.

Of course, the best course of action is to give up the tobacco habit entirely.  It’s not only best for the health of the smoker, it will also greatly reduce risks for pets. Understanding that it’s not easy to quit this addictive habit, people who smoke and have pets should attempt to minimize their pets’ exposure by smoking outdoors.

Smoking in the car with pets can create a toxic environment, even with the windows open.  Some states and Canadian provinces even ban smoking in cars when children are passengers.  If you must smoke when you drive, leave your pets and kids at home.

In the past 45 years, the number of smokers in the United States has decreased to less than 20% of the population and almost 70% of those current smokers want to kick the habit. Could an understanding of how secondhand smoke affects our pets help encourage more people to quit? When I practiced in Connecticut, I do remember one client who quit smoking when her cat was diagnosed with feline asthma which was aggravated by cigarette smoke!

Prepare for Disaster with Your Pet in Mind

Thankfully we don't get hurricanes in Wisconsin, but we do see flooding, tornadoes and other disasters, sometimes with no warning at all.  While many of us are sending money for relief efforts after Superstorm Sandy, we should also take some time to prepare here in Wisconsin. A little disaster preparation can really help, especially for pet owners.  Listen to Linda's story about Rock River flooding a few years ago.

Many pets are left behind when disaster strikes. When food and water are in short supply, it can be hard to provide for our four legged friends. Here are some suggestions to help prepare:

• Have your pet microchipped. If you are separated from your pet, the microchip will help you find them if they end up at a shelter or veterinarian's office.
• Make a disaster kit. Include things like a flashlight, cash and food and water for both you and your pet. Banks and ATM's may not be functioning if the power is out and pet food may be hard to find. Clean drinking water is most important in survival situations.
• Leash and pet carrier. Pets and people can get very stressed and upset in disaster situations. Keeping pets contained can keep them safe. 

Check out other suggestions at hallettvet.com and start building your pet friendly disaster kit now.