Dr. David Hunley, DVM, DACVIM (Oncology) – Gold Coast Center for Veterinary Care
Cancer in dogs and cats
About 1 in every 4 dogs and cats will develop some form of cancer in their lifetime, and the incidence of cancer-development increases with age (there is a higher risk in dogs and cats over 10 years of age). Most of the cancers we treat in veterinary medicine occur due to genetic factors (often breed-related), so it is difficult to avoid the development of cancer in the majority of dogs and cats. Once cancer does develop, it is important to make a diagnosis as quickly as possible so that we can evaluate the various treatment options and make a therapeutic plan based on the specific cancer type.
It is always difficult to hear a diagnosis of cancer, whether it is in our human, canine, or feline family members. The word cancer carries with it a stigma that is different than most other illnesses, and it can seem like there is no hope once this diagnosis is made. The important thing to remember, however, is that there are many different forms of cancer, and no two cancers are exactly the same. Just as there are some situations where we are dealing with an aggressive cancer that has few treatment options, there are also many time when we can effectively treat, control, and sometimes cure cancer.
Signs of cancer in dogs and cats
Just like in people, cancer can affect any organ in the dog and cat, so we could have cancers that arise from the skin or from the internal organ. If any of the following symptoms arise, they could indicate that a cancerous process is present, so they should be evaluated, but other problems can cause these symptoms as well.
- New or rapidly-growing lumps or bumps in or under the skin
- Persistent non-healing wounds
- Persistent diarrhea and/or vomiting
- Persistent, unexplained pain or lameness
- Bleeding from the mouth, very bad breath, or dropping food from the mouth
- Bleeding from the nose
- Abdominal swelling
- Difficulty breathing or persistent cough
- Sudden changes in weight or appetite
What to do if your pet is diagnosed with cancer
Your veterinarian will usually make the initial diagnosis of cancer and will discuss options with you. In some cases, they will be comfortable starting treatment, while in others, they may advise seeing a veterinary oncologist for a more detailed evaluation and discussion.
The role of a veterinary oncologist is to evaluate the individual characteristics of each dog’s or cat’s cancer and help make a plan for the best course of action moving forward. This plan will be determined in part by the type of cancer that is found, in part by the health of your pet, and in part by your comfort level with the treatment options that are available. There are some situations where no treatment is needed or when surgical removal of a cancerous mass is likely to control the cancer long term. Other times, medical treatment is recommended. Medical treatment options may include chemotherapy or other cancer-fighting medications.
Chemotherapy is a word that is generally associated with negative thoughts and feelings. This is because we know chemotherapy drugs can cause unwanted side effects. However, it is important to remember that there are many different types of chemotherapy and many different ways that chemotherapy can be administered. Also, certain types of cancer are more likely to respond to chemotherapy than others, so in some cases, it is reasonable to risk side effects while in others it may not be. It is often said that dogs and cats tolerate chemotherapy better than people do, and this is true in many instances, but this is partly due to the fact that we tend to be less aggressive with the chemotherapy dose and intensity in veterinary patients in order to avoid problems as much as possible. Despite this strategy of treatment, we still do see severe side effects in some dogs and cats, but the side effects in most veterinary patients are mild and tolerable, and there truly are many dogs and cats who have no side effects at all.
For many cancers, there are medical treatment options other than chemotherapy that may be less likely to cause side effects. These options vary depending on the type of cancer and the details of the disease, but they can be a more desirable approach for some situations. If less aggressive options are available, they will always be discussed during an oncology consultation.
Since each dog or cat is an individual, their cancer is unique, and their potential response to treatment is also unique. Therefore, it can help to discuss your pet’s diagnosis and your thoughts and concerns with an oncology specialist to make sure you have the most detailed information about your pet’s diagnosis and that you are comfortable with your decisions moving forward.