Chemotherapy drugs are compounds that are toxic to cancer cells. They may be administered orally, by intravenous (IV), subcutaneous (under the skin), intramuscular (IM), or intracavitary (chest or abdomen) injection.

 

 

Cancer cells generally multiply very rapidly. Most chemotherapy drugs work by damaging the ability of these rapidly growing cells to divide, eventually killing them.

 

 

Chemotherapy is used by the veterinarians at MedVet Memphis to treat cancer in four different ways:

 

Chemotherapy is the most effective single treatment for some types of cancer, offering the best opportunity for remission, and improved survival, while at the same time preserving a good quality of life. A good example of this type of cancer is lymphoma, also called lymphosarcoma.

 

Chemotherapy is often recommended after surgical removal of a malignant cancer. The purpose of chemotherapy in this setting is not only to try to prevent recurrence of the cancer at the original site, but also to try to prevent spread (or metastasis), and improved survival. Examples of cancers in which chemotherapy is routinely used in this way are canine or feline malignant mammary cancer and canine bone cancer.

 

Chemotherapy may be administered to some animals while they are also receiving radiation therapy for the treatment of their cancers. Some chemotherapy drugs are effective in this situation because they increase the ability of the radiation to kill the cancer cells. This type of chemotherapy is referred to as radiosensitizing chemotherapy.

 

Occasionally, chemotherapy will be used alone for the treatment of cancers that are not amenable to surgical removal or radiation therapy, or for cancer that has already metastasized. In these cases, the goal of treatment will not be to cure the cancer, but rather to improve the patient’s quality of life temporarily by reducing pressure, bleeding, or pain.

 

 

There are some risks involved with any type of treatment for cancer. Some normal cells will be injured and killed by the chemotherapy drugs. Some side effects may be apparent because of these normal cells being killed, for example gastrointestinal upset. Usually these side effects are outweighed by the benefits of killing cancer cells.

 

Dogs and cats generally tolerate chemotherapy much better than human patients. The two side effects encountered most commonly in canine and feline patients receiving chemotherapy are toxicity to the gastrointestinal tract and to the bone marrow. Normal cells in both of these areas divide very rapidly, so they are more susceptible to the toxic effects of the chemotherapy.

 

When the lining cells of the gastrointestinal tract are affected, the result may be nausea, vomiting or diarrhea. Most patients will experience these side effects once or twice during their course of chemotherapy treatment, but the symptoms are usually mild, short-lived, and can be overcome with supportive care at home.

 

When the cells of the bone marrow are affected, the result may be more serious. The progenitor cells, which produce the white blood cells necessary to fight infection, are found here. If these progenitor cells are damaged, the patient’s white blood cell count may drop low enough to result in an increased susceptibility to infection. Even bacteria, to which a patient would normally be resistant, such as normal intestinal bacteria, can cause serious illness in this situation. White blood cell counts of all canine and feline chemotherapy patients are monitored carefully, but rarely a cat or dog receiving chemotherapy will develop a life-threatening systemic infection. This is why it is important to closely adhere to our recommendations for repeat blood tests. If your pet’s white blood cell count is low without a fever or illness we may recommend a short course of antibiotics and monitoring the temperature at home. If your pet becomes systemically ill or has a fever with a low white blood cell count we admit your pet to the hospital for intravenous fluids and antibiotics.

 

Hair loss in cats and dogs receiving chemotherapy is usually very minor, with some notable breed exceptions. If you own a poodle, Old English sheepdog, schnauzer, Puli, Lhasa apso, Shih Tzu, or Maltese, you should expect that your pet would lose a significant amount of hair during the initial stages of chemotherapy. The hair that is lost usually grows back after your dog’s course of chemotherapy has been completed, or once treatments are being administered less frequently. Your dog may have hair that changes in texture and color and return of hair may be prolonged in areas that are shaved. Cats usually do not lose any hair, although many will lose their whiskers.

Some chemotherapy drugs can be extremely irritating to the subcutaneous tissues if they leak outside the vein during injection. Examples include the chemotherapy drugs vincristine, vinblastine, doxorubicin (Adriamycin®), and nitrogen mustard; severe inflammation, ulceration, and swelling can occasionally be seen. However, this complication occurs infrequently, because these drugs are carefully administered through catheters by experienced technicians and doctors.

 

 

Your pet will be examined by one or more cancer specialists. These specialists will determine whether chemotherapy will be a useful part of your pet’s cancer therapy. If chemotherapy is given to your pet, a veterinarian specially trained in oncology (cancer medicine) will plan the course of therapy carefully, and a member of the oncology service will administer each treatment. Treatment for each patient is individually tailored, although specific chemotherapy protocols consisting of several different drugs are followed for different types of cancer.

 

The majority of chemotherapy used at MedVet Memphis is administered by intravenous injection. In most cases, treatment can be given on an outpatient basis. However, it is important to realize that, barring unforeseen delays, it will generally take at least 3 to 6 hours from the time a patient is checked in to the time they leave the hospital. Treatments with certain chemotherapy drugs, such as cisplatin, DTIC, and Ifosfamide, take the entire day.

 

It is the owner’s responsibility to make an appointment for each outpatient visit for chemotherapy. Most owners find it easiest to make a series of appointments well in advance. Chemotherapy patients are treated Monday, Tuesday, and Friday. A typical day involves dropping your pet off in the morning between 7:30-10:00 a.m. Your pet will receive a physical examination by our doctors, and diagnostic tests such as bloodwork will be performed. If everything is fine, your pet will be treated with chemotherapy, and will generally be ready for pick-up after 2 p.m. Some days may be longer, depending on the treatment required and the number of patients that need treatment. Pets need to be picked up prior to 6 p.m. unless prior arrangements have been made with your doctor. In some instances, we may need to delay treatment. We appreciate your patience, and will do our best to make this a pleasant and efficient process for you and pet!

 

 

 

Treatment of cancer with chemotherapy can be costly. It involves the use of the same drugs used to treat human cancer patients, and many of these drugs are expensive. In addition, your pet will benefit from the expertise of several highly trained animal health care professionals. The exact cost of chemotherapy varies with the size of the animal, number of treatments, and the drugs being administered. The projected cost of your pet’s individual treatment will be discussed in detail with you. MedVet Memphis also accepts Care Credit.

 

 

The length of a particular course of chemotherapy protocol will vary depending on the disease being treated. The most common veterinary cancer treated with chemotherapy is lymphoma. Although chemotherapy for this disease is often very successful, owners of cats and dogs with this type of cancer should realistically expect that their pets will need some form of chemotherapy for the rest of their lives. The course of treatment for other types of cancer is usually much shorter, generally 12 to 15 weeks. The specific length of your pet’s individual course of treatment will be discussed in detail with you.

 

 

 

 

 

If you think your pet is seriously ill and needs immediate medical attention, you should go directly to your veterinarian, an emergency veterinary clinic, or PetMed emergency. You will be seen by an emergency doctor, who will determine if hospitalization is necessary.

 

 

 

 

 

It is important for your veterinary oncologist to examine your pet periodically after chemotherapy treatment has been discontinued, usually at 1 to 3 month intervals. This will allow potential problems, such as recurrence of cancer, to be detected before they become too advanced. Treatment options will be more numerous, and have a greater potential for success when problems are identified early.

 

Finally, it is important for the owners of dogs and cats receiving chemotherapy to realize that cancers we treat are rarely cured. Almost all of our patients ultimately have recurrence of their cancers. It is vital to understand that most cats and dogs receiving chemotherapy have an excellent quality of life both during and after treatment. It is often possible to provide many additional months, or sometimes even years, of happy life with chemotherapy. The vast majority of owners tell us that they have no regrets about their decision to pursue chemotherapy for their pet and they would pursue treatment if they had to make the decision again.

 

 

 

 

 

 

If your pet goes home with a bandage wrapped around the leg where chemotherapy was administered it should be removed the same day. Otherwise, circulation will be compromised, and the paw may swell later.

Check the injection site one to two times a day to make sure the area looks normal. If this area is swollen, red, or looks abnormal, please call your veterinarian or MedVet Memphis.

Some chemotherapeutic drugs can cause damage to the tissue if they get outside the vein (perivascular) and come in contact with other tissues. If this is suspected, you will be advised on specific treatments by your doctor.

If your pet is licking excessively at the injection site, contact your veterinarian.

It is important to minimize our exposure to chemotherapy and common sense precautions should be taken.

 

If you are administrating oral chemotherapy at home:

Keep the medication in the vial, and do not store it in the kitchen.

Ensure children and pets do not have access to the drugs.

Do not eat, drink, or chew gum when giving the medication.

Do not crush or break the pills.

Wear latex gloves when handling the medication. Dispose of the gloves promptly, and wash your hands thoroughly after administration.

Gloves and empty vials can be returned to the hospital for disposal.

It is normal that a small amount of chemotherapy is excreted in the urine, feces, and vomit, usually within the first 48 hours after administration. Wear gloves for handling of feces or urine (i.e. if they have an accident in the house/apartment).

Soiled bedding should be washed as you normally would.

Wash skin thoroughly. If your skin becomes irritated, contact your physician.

Use detergent to clean floors, carpets, or countertops. Wear gloves when cleaning.

If you are pregnant, trying to become pregnant, or are breast-feeding:

Please avoid contact with these drugs.

Avoid contact with your pet’s waste for 72 hours after chemotherapy has been given.

Please contact your physician with any further questions.

If you are immunosuppressed or are taking immunosuppressive medication:

Please avoid contact with these drugs.

Avoid contact with your pet and your pet’s waste for 72 hours after chemotherapy has been given.