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When is Chemotherapy Recommended for Dogs and Cats?

Chemotherapy can be a scary word, especially if you, a family member, or friend have received chemotherapy treatments. However, chemotherapy in dogs and cats is well tolerated, with a much lower potential for side effects. In dogs and cats, we use more gentle doses and schedules of chemotherapy, as our most important goal with treatment is to maintain excellent quality of life.

While side effects such as stomach upset and drops in cell counts can occur, they are infrequent, and can often be managed with medications at home. In addition, most dogs and cats do not lose their hair while on chemotherapy.


My Pet Was Diagnosed with Cancer, Now What?

After a pet is diagnosed with cancer, we look at several factors to determine if chemotherapy is recommended, including biopsy findings, and the results of cancer staging tests.

When a tumor is surgically removed, it is submitted for biopsy (microscopic evaluation), and the pathologist provides a tumor diagnosis, a tumor grade, and an evaluation of surgical margins. The grade of a tumor influences chemotherapy recommendations. Low grade tumors are often controlled long-term with just surgical removal. High grade tumors (such as bone tumors, hemangiosarcoma, and high-grade mast cell tumors) are more aggressive cancers, and they have the potential to spread to other areas of the body (metastasis). In these cases, chemotherapy is often recommended after the tumor has been surgically removed.

In addition, we also recommend staging tests in pets that have been diagnosed with cancer. Cancer staging includes bloodwork, imaging tests (such as chest x-rays and abdominal ultrasound and needle samples, often from lymph nodes and organs such as the liver and spleen. Cancer staging helps us to determine the extent of cancer within a pet’s body.

Some tumors can begin in one location and then spread over time to other locations in the body, such as the lymph nodes or lungs. If there is evidence of metastasis on these staging tests, chemotherapy may be recommended.

For Some Cancer Types Chemotherapy is the Treatment of Choice

Some cancer types, such as lymphoma and leukemia, are systemic cancers. These cancers affect multiple areas of the body simultaneously, and therefore they often cannot be treated with localized treatment options, like surgery or radiation therapy. For these cancers, chemotherapy is the treatment of choice. The goal of chemotherapy is to induce clinical remission, which means that enlarged lymph nodes go back to normal size, bloodwork abnormalities resolve, and pets are energetic and eating well at home. We monitor our patients by reassessing their physical examination, lab work, and/or imaging tests to assess their response to treatment.

When is Chemotherapy Most Effective?

After a pet is diagnosed with an aggressive cancer, we may recommend starting a chemotherapy protocol to improve their long-term prognosis by slowing down cancer progression. By slowing down cancer progression, we can extend life and improve energy levels, alleviate discomfort, and encourage a healthy appetite.

Chemotherapy works best when it is targeting microscopic tumor cells, so it is ideal to start a chemotherapy protocol before there is evidence of metastasis identified on imaging tests. If your pet recently had surgery to remove a tumor, we recommend starting chemotherapy when the surgical incision is completely healed (typically 2 weeks post-operatively).

How is Chemotherapy Administered?

Most chemotherapy drugs are injections given in the hospital by highly trained oncology technicians.

Some chemotherapy drugs are oral medications that are administered at home by pet owners. When pets come to MedVet for chemotherapy, we start with a physical examination, and lab work to evaluate cell counts. Next, the chemotherapy treatment is administered. Treatment times vary from quick injections to longer infusions given over 30 minutes. For patients receiving oral chemotherapy, we perform regular rechecks to ensure that treatment is effective and well-tolerated.

A Better Patient Outcome

At MedVet Cincinnati, our goal is always to promote excellent quality of life and to keep your pet an active, happy member of your family for as long as possible. Chemotherapy is one of the ways we can accomplish this. For more information, ask your family veterinarian for a referral to an oncology specialist. You can also visit our online Medical Oncology Resource Guide.


Photo: Robb McCormick Photography – https://www.robbmccormick.com

Jeanne Lane, DVM, Diplomate, ACVIM (Oncology) is a Board-certified Veterinary Medical Oncologist at MedVet Cincinnati where she has been part of the team since 2018.

Dr. Lane earned a Bachelor of Science degree in Animal Science, graduating Summa Cum Laude, from the University of Connecticut in Storrs, CT followed by a Doctor of Veterinary Medicine degree from the Tufts Cummings School of Veterinary Medicine in North Grafton, MA. She then completed a rotating internship in small animal medicine and surgery at VCA Veterinary Care in Albuquerque, NM as well as a Medical Oncology Residency at the University of Tennessee College of Veterinary Medicine in Knoxville, TN.

Dr. Lane has a special interest in the early detection of cancer, novel therapies for lymphoma, and helping to ensure a high quality of life for her Patients as they undergo cancer therapies. She strives to ensure that families understand their pet’s condition, the available treatments, and what they can expect during the treatment protocol. She finds developing a close relationship with the Patient and their family throughout the treatment protocol to be the most rewarding part of being a Board-certified Veterinary Medical Oncologist.

When not caring for her Patients, Dr. Lane enjoys photography, running, and spending time with her husband and two sons.

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