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Medical Oncology

Medical oncology is the use of chemotherapy, hormone therapy, or other drugs to treat cancer.



Chemotherapy is used to treat cancer at the tumor site, as well as the cancer that may have spread through the body. Most chemotherapeutic drugs act directly on cancer cells, preventing them from maturing or reproducing. Unlike humans, the side effects of chemotherapy in pets are relatively mild. Doses of drugs and treatment schedules are calculated to minimize discomfort to the pet, while providing the most effective defense against the cancer. As a result, most people are surprised at how well their pets feel while undergoing chemotherapy. The goal is to kill and slow the growth of cancer cells, while producing minimal negative effects on normal cells. If your pet requires a plan of chemotherapy, your veterinarian will most likely bring in a specialist (an oncologist) to develop the plan of attack and administer the treatments. In addition to the latest and best medical treatments, an oncologist will provide the specialized equipment and supervision that your pet needs. Chemotherapy protocols are frequently changed or customized to achieve the best outcome for your pet.


Immunotherapy is the use of the body’s immune system to treat a disease. We use immunotherapy to treat certain cancers, such as: melanoma, hemangiosarcoma, renal cell carcinoma, multiple myeloma, and lymphoma among others. There are various types of immunotherapy ranging from cancer vaccines to injecting cytokines (chemicals that stimulate the body’s own immune system). One of the advantages of immunotherapy is that it is generally less toxic than traditional chemotherapy.

Our oncology department is equipped to treat the following cancers:

  • Lymphoma
  • Mast cell cancer
  • Transitional cell carcinomas
  • Hemangiosarcoma
  • Anal gland carcinoma
  • Osteosarcoma
  • Soft-tissue sarcoma
  • Melanoma
  • Nasal carcinoma
  • Mammary gland tumors
  • Thyroid adenomas and carcinomas
  • Brain and spinal cord cancer

Medical Oncology FAQS

Service FAQs

Chemotherapy is a systemic therapy, meaning it works throughout the body, as opposed to radiation therapy which is a local or regional therapy. Chemotherapy is used when a cancer or tumor has already spread (or metastasized) or when there is a high risk of the tumor spreading.

Many types of cancers are treated with chemotherapy. The most common tumor being lymphoma, a systemic cancer of part of the immune system. Osteosarcoma (bone cancer) and hemangiosarcoma are both treated with chemotherapy because of the very high likelihood of metastasis (spreading), even after the tumor is removed. Many other types of cancers such as mast cell tumors, mammary gland tumors, bladder cancer, and many others are often treated with chemotherapy.

Chemotherapy can be administered orally in the form of a pill or injected into a vein (intravenous), into a body cavity (such as the chest or bladder), into a muscle (intramuscular), or into the spinal fluid (intrathecal). Currently, most chemotherapy is administered intravenously; however, oral chemotherapy drugs are gaining wider use.

Chemotherapy in pets is very different from chemotherapy in people. We use much lower doses of chemotherapy and spread the treatments out over a much longer period of time. This is done to try and allow us to treat your pet's cancer effectively without causing the side effects that occur in people. In addition, there have been tremendous advances in medications that are used to prevent the common side effects of chemotherapy-vomiting, diarrhea and loss of appetite. Cerenia is a relatively new drug and it is quite effective at preventing or stopping nausea and vomiting. There are also regimens that we have developed that dramatically reduce the side effects of diarrhea and loss of appetite. We are as concerned as you are about maintaining the highest quality of life for your pet-both during and after treatment.

Most chemotherapy is given in an outpatient setting, typically over a 5 to 45 minute time period. Some chemotherapy is given slowly over a few hours, but our team will alert you when this is needed. Most animals do not need to be fasted before chemotherapy, but we will make recommendations based upon your pet's unique circumstances.

Most pets-80-90%- have no, or minimal, side effects after chemotherapy. Vomiting, diarrhea, loss of appetite and loss of energy are the four most common side effects, but if these do occur they are usually mild. Your oncologist will discuss ways of preventing these side effects, as we have found that it is easier to prevent them than it is to treat them once they begin. Greater than 95% of our clients were pleased with how their pets handled therapy at our practice and would do it again.

When a tumor is immunogenic—recognized as foreign by the body—immunotherapy can be very effective. We are actively engaged in research to find what tumors are immunogenic and what types of immunotherapy work in dogs and cats.

The most common tumor is melanoma. A tumor vaccine, the first of its kind in veterinary medicine, was developed to treat this disease and its use has revolutionized the way we treat this disease. Other vaccines for other types of cancers are currently in development.

Subcutaneous methods consist of administration through subcutaneous routes, i.e., injections as well as infusions over time.

The main side effects of this type of therapy are “flu-like” symptoms of malaise and loss of appetite.

Typically, no preparation is necessary for this type of treatment.

Your pet may be slightly lethargic and have a decreased appetite for a few days. The tumor may not respond initially, as immunotherapy may take weeks to months to work.