Finding out that your pet has cancer can be a very difficult and emotional experience. While some cancers can be treated successfully with surgery alone, many cases require additional treatments like chemotherapy or radiation to help extend your pet’s life. Chemotherapy in pets is different from the chemotherapy that humans undergo. The goal is not necessarily a cure, but rather to improve the pet’s quality of life and extend their time with their family. This handout explains what chemotherapy for pets involves, what side effects to expect, and how you can support your pet during treatment.

What is Chemotherapy?

Chemotherapy is the systemic administration of cancer-fighting drugs. These drugs are given at the highest maximum tolerated dosages (MTD) to destroy cancer cells. The primary goal of chemotherapy is to disrupt cell division by targeting rapidly dividing cells, such as those found in tumours. However, because these drugs can’t differentiate between cancer cells and normal, healthy cells, side effects can occur. It’s important to note that chemotherapy drugs in veterinary medicine are given in lower doses compared to humans, with the aim of improving your pet's quality of life rather than curing the cancer.

Chemotherapy in Pets: Side Effects

While chemotherapy can be an effective treatment, it does come with potential side effects. However, the side effects pets experience are usually different and less severe than those seen in humans.

• Bone Marrow Suppression: This can lead to decreased production of blood cells, which might cause your pet to be more susceptible to infections or experience fatigue.
• Alopecia (Hair Loss): Some pets, particularly certain breeds like Shetland Sheepdogs and Poodles, may experience hair loss. This is not as widespread as in humans and is typically breed-specific.
• Gastrointestinal Signs: Pets may experience vomiting, diarrhoea, or a decrease in appetite. These symptoms are usually temporary and can be managed with supportive care.
• Specific Side Effects: Each chemotherapy drug has its own specific set of potential side effects. We will discuss these in detail if your pet is undergoing chemotherapy and will provide guidance on how to manage them.

It’s important to know that 80-90% of pets will remain asymptomatic (i.e. they will show so symptoms) and tolerate the treatment well. However, 10-20% may experience some of the side effects mentioned above, and in rare cases, less than 1% of pets may have severe reactions that can be life-threatening.

Types of Chemotherapy Treatment

The treatment your pet receives will depend on the type of cancer and your pet’s overall health. There are two primary forms of chemotherapy for pets:

• Intravenous (IV) Chemotherapy: This involves administering the chemotherapy drugs directly into your pet’s vein.
• Oral Chemotherapy: Some cancers can be treated with oral chemotherapy medications that your pet can take at home.

The duration of chemotherapy treatment will also depend on the type of cancer. Some pets may require only a few treatments, while others may need ongoing cycles of chemotherapy. Regular follow-up visits and blood tests will be required to monitor your pet’s progress and adjust the treatment as needed.

Monitoring During Treatment

Your pet will be closely monitored during chemotherapy treatment to ensure they are not developing severe side effects. Blood tests are commonly used to assess bone marrow function and organ health. If side effects do occur, there are various treatment options available to help manage them and ensure your pet remains comfortable throughout the process. This may include medications to control nausea, diarrhoea, and appetite loss, or adjustments to the chemotherapy schedule.

What to Expect During Treatment

• Chemotherapy Treatments: You will need to bring your pet in regularly for their chemotherapy sessions, which may require travel and time commitment.
• Follow-Up Blood Tests: Regular blood tests will be needed to check your pet’s blood count and monitor for any potential side effects.
• Improvement in Quality of Life: Many pets show improvement in their condition after starting chemotherapy. Although chemotherapy isn’t a cure, it can extend their life and improve their comfort and overall well-being.

Things to Consider

When deciding whether to pursue chemotherapy for your pet, there are a few important factors to consider:

• Costs: Chemotherapy can be expensive, depending on the drugs used and the number of treatments required.
• Time Commitment: Chemotherapy often requires multiple visits to the veterinary surgery for treatment and follow-up tests. Be prepared for this time investment.
• Emotional Considerations: Chemotherapy can be an emotional journey, both for you and your pet. While many pets tolerate the treatment well, it can still be a challenging process, and you will need to be ready to provide emotional support for your pet.

If you have any concerns or questions about chemotherapy for your pet, don’t hesitate to contact us. We will provide you with guidance, support, and the best care options tailored to your pet’s needs.