Broadly speaking, chemotherapy involves using different medications to treat cancer. There are many kinds of chemotherapy medications, and they work in multiple different ways. Some chemotherapy medications are injectable, and some are oral (pills).
Chemotherapy for Dogs and Cats:
In veterinary oncology, our first and most important treatment goal is maximizing each patient’s quality of life. Therefore, we have a very low tolerance for side effects. When deciding on any chemotherapy plan, we will discuss any potential side effects in detail. We will also make some protocol changes to customize the plan for your pet in particular. If at any time your pet has a concerning side effect, we will adjust the remainder of the plan to minimize the chance of the problem occurring again.
Although most dogs and cats generally do well with chemotherapy, the most common side effects are nausea, decreased appetite, diarrhea, and transient bone marrow suppression. These side effects are generally mild and self-resolve at home, although occasionally a patient will have a serious side effect. With most drugs and protocols, less than 5% of patients have side effects that are bad enough to require a hospital stay.
Here are some suggestions to minimize the risk and severity of any potential side effects:
Nausea- Dogs and cats who are nauseated may lose their appetite, approach food and then turn away, salivate, lick their lips, gulp, or vomit. We will send home an anti-nausea medication to give for the first several days after each in-hospital chemotherapy treatment. Please let us know if you notice any of these signs- we can try an additional anti-nausea medication and/or a bland diet if needed.
Diarrhea- If your pet develops diarrhea that is relatively mild, we can first try a fiber supplement at home, as well as a probiotic and/or a bland diet. If the diarrhea persists or worsens (or if you notice blood or black material in the stool), please let us know right away.
Bone marrow suppression- This side effect usually does not cause patients to feel unwell; it is something that we look for on the bloodwork after each dose of chemotherapy. If the white blood cells are low, a brief course of antibiotics may be needed. Rarely, patients develop a fever or feel unwell with a low white blood cell count- if this happens, your pet should briefly stay in the hospital for intravenous fluids, antibiotics, and supportive care.
Dogs and cats may also lose their whiskers and guard hairs during treatment, resulting in a softer coat overall. Dogs with continuously growing hair coats may lose a majority of their hair coat during treatment, although regrowth of the coat generally occurs once treatment is complete. The hair may come back a different color or texture! Some of the more common breeds at increased risk for this include Poodles and Poodle mixes, Malteses, Bichon Frises, curly-coated breeds, some Terriers, and occasionally Golden retrievers.
Unless we discuss otherwise during your appointment, your pet should continue to take their flea/tick/heartworm preventative medications during chemotherapy treatment. If your pet is feeling off or if they have received chemotherapy the day before, it is reasonable to delay administration of these preventatives.
Your dog can continue to go for walks, swim (weather permitting), and play. They may continue to play with other dogs at your own discretion. As long as your dog is feeling well, exercise restriction is not needed.
Cats can continue to socialize with other pets in the house during treatment, as long as they are not feeling sick.
Please let us know when your pet becomes due for vaccines, and we will discuss at that time if it is recommended to vaccinate your pet at that point in their treatment.
Chemotherapy Safety at Home:
When dogs and cats are given a chemotherapy drug, small amounts of the drug and its breakdown products are eliminated in the urine and feces afterwards while the body processes and gets rid of them.
The amount that is present is variable, depending on the drug and the individual patient. Although most of the drug will be gone within 5 days, trace amounts of chemotherapy have been detected in urine up to 21 days after a treatment.
Please follow these guidelines to minimize any exposure to trace amounts of chemotherapy:
For dogs:
– For 5 days after chemotherapy is given, please avoid contact with your dog’s feces, urine, vomit, and saliva. If contact occurs, please wash your hands thoroughly with dish detergent and water.
– If you are cleaning up indoor urine, feces, or vomit during this timeframe, please wear gloves, clean the area with dilute bleach after removing any liquid or solid material, and wash your hands afterwards.
– Please encourage your dog to eliminate in a low-traffic, sunlit area during this timeframe.
– Children, as well as humans who are pregnant, nursing, or trying to become pregnant should avoid contact with your dog’s urine, feces, vomit, and saliva during this timeframe.
For cats:
– For 5 days after chemotherapy is given, please avoid contact with your cat’s feces, urine, vomit, and saliva. If contact occurs, please wash your hands thoroughly with dish detergent and water.
– If you are cleaning up urine, feces, or vomit during this timeframe, please wear gloves, clean the area with dilute bleach after removing any liquid or solid material, and wash your hands afterwards.
– Please clean your cat’s litter box daily, and double-bag waste before discarding it in the trash. Avoid inhaling litter dust, wear gloves, and wash your hands afterwards.
– Children, as well as humans who are pregnant, nursing, or trying to become pregnant should avoid contact with your cat’s urine, feces, vomit, and saliva during this timeframe. These individuals should not be in charge of cleaning the litter box.
If you are giving oral chemotherapy at home:
– Please wear gloves, and thoroughly wash your hands afterwards.
– Children, as well as humans who are pregnant, nursing, or trying to become pregnant should not be in charge of giving oral chemotherapy.
– Please be sure the chemotherapy pills are stored safely out of reach of children and pets.
– Please do not crush or split pills, or dissolve them into a slurry. Also, please do not leave pills unattended in food to be eaten later. Chemotherapy pills must be given intact, either on their own or wrapped in a treat.