If your pet has a lump or isn’t feeling well, your veterinarian may recommend tests to determine if cancer is present and what type it might be. Some tumors are harmless (benign), while others are cancerous (malignant). The veterinarian will use different tests to understand the nature of the tumor to create the best treatment plan for your pet.

Common Diagnostic Tests:

• Complete Blood Count (CBC): Checks red and white blood cell levels, as well as platelets, to get an overall picture of your pet’s health.
• Chemistry Panel: Measures how well organs like the liver and kidneys are functioning.
• X-rays (Radiographs): Helps detect tumors or abnormalities inside the chest or abdomen.
• Fine Needle Aspirate (FNA): A simple procedure where a small needle collects cells from a lump for closer examination under a microscope.
• Cytology: Examines cells from the lump to determine whether they are cancerous.
• Biopsy: A procedure where a small piece of tissue is taken from the tumor and analyzed to confirm if it’s cancer. This is usually done under anesthesia.
• Excisional Biopsy: If possible, the veterinarian may remove the entire tumor along with some surrounding healthy tissue in the hopes that all cancerous cells are taken out.
• CT Scan: Creates a detailed 3D image of the body, helping the veterinarian see the tumor’s size, location, surgical feasibility and whether the can has spread. This is done under anesthesia.
• MRI (Magnetic Resonance Imaging): Uses magnetic fields to get a clearer image of soft tissues, such as the brain and spinal cord. This is done under anesthesia.
• Ultrasound: A way to examine organs like the liver, kidneys, or heart using sound waves.

Each of these tests helps your veterinarian understand the cancer type, how far it has spread, and the best course of action for your pet’s treatment.

Choosing the best treatment for your pet’s cancer can feel overwhelming, but your vet is there to help guide you. First, your veterinarian or a veterinary cancer specialist (board-certified oncologist) will diagnose the cancer by determining its type, how aggressive it is, and whether it has spread. Once they have a clear picture, they will go over treatment options, which may include surgery, chemotherapy, radiation, immunotherapy, or a combination of these.

Every treatment has benefits effects as well as possible side effects, so it’s important to talk through each option with your veterinarian. Your pet’s overall health and comfort level will also play a big role in deciding the best path forward.

Cancer Treatment Options for Pets

Cancer treatment depends on the type, size, and location of the tumor. Common treatments include:

• Surgery: Removing the tumor when possible.
• Chemotherapy: Special medicine to slow or stop cancer growth. Pets usually handle this well with few if any side effects.
• Radiation Therapy: High-energy waves target to shrink tumors. Pets usually handle this well with few if any side effects.
• Immunotherapy: Boosts the immune system to help fight cancer.

Your veterinarian will help you choose the best option based on your pet’s condition and quality of life.

Chemotherapy is a treatment that helps kill certain cancer cells and/or helps stop cancer cells from growing and spreading in the body. It works by targeting these cells, either at the original tumor site or in other areas where cancer may have spread. Unlike in humans, chemotherapy pets handle chemotherapy much better, therefore; side effects are usually mild.

Many pet parents are surprised at how well their pets tolerate chemotherapy. The goal is to slow the cancer down while keeping your pet with a good quality of life. If chemotherapy is the best option, your vet may refer you to a veterinary oncologist (a board-certified cancer specialist) who will develop a treatment plan and provide specialized care.

When is Chemotherapy Used?

Chemotherapy is usually recommended in these situations:

• When cancer has already spread (metastasized) to other parts of the body.
• When there is a high risk that the tumor could spread.
• When a tumor cannot be completely removed with surgery.

Types of Cancer Commonly Treated with Chemotherapy

Some cancers respond especially well to chemotherapy, including:

• Lymphoma: A cancer of the immune system that often affects the lymph nodes.
• Osteosarcoma: A type of bone cancer that has a high risk of spreading.
• Hemangiosarcoma: A cancer of the blood vessels that often spreads quickly.
• Mast Cell Tumors, Bladder Cancer, Mammary Gland Tumors, and More: Many other cancers can also be treated with chemotherapy.

How is Chemotherapy Given?

Chemotherapy can be given in different ways, depending on the type of cancer and how advanced it is. The most common methods include:

• Oral (Pills): Given at home or at the veterinarian’s office.
• Intravenous (IV): Given through a vein during a short veterinary visit.
• Injection: Given into a muscle or directly into a body cavity like the chest or bladder.

Your vet will determine the best method for your pet’s specific needs.

Side Effects: What to Expect

Chemotherapy for pets is much gentler than in humans. Most pets (about 80-90%) experience little to no side effects. If side effects do occur, they are usually mild and can include:

• Temporary loss of appetite
• Nausea or vomiting
• Diarrhea
• Decreased energy for a few days

Veterinary medicine has come a long way in preventing side effects. For example, medications like Cerenia can help prevent nausea, and treatment plans are adjusted to keep your pet as comfortable as possible.

How to Prepare for Chemotherapy

Most chemotherapy treatments are done on an outpatient basis, meaning you’ll bring your pet in for a visit that usually lasts between 30 to 45 minutes. Some treatments take longer, but your veterinary will let you know in advance.

Most pets do not need to fast before chemotherapy but always check with your veterinarian in case specific instructions apply to your pet’s treatment plan.

What Happens After Treatment?

As most pets handle chemotherapy well, they return to their normal routine quickly. If side effects happen, they are usually mild and go away within a couple to a few days. Your veterinarian will give you guidance on how to manage any potential discomfort.

80%-90% of pet owners who choose chemotherapy are happy with their decision and feel their pet’s quality of life remains high during treatment. With the right approach, many pets continue to enjoy life, spending more quality time with their families.

Radiation therapy has been used in veterinary medicine for decades and has advanced significantly over time. Today, modern imaging techniques like MRI and CT scans help veterinarians pinpoint tumors more accurately. Newer radiation technology allows for precise targeting of cancer cells while protecting healthy tissue, making treatment more effective while reducing side effects.

When is Radiation Therapy Used?

Radiation therapy is often used in combination with surgery or chemotherapy to help control or eliminate tumors or when surgery is not an option. This is particularly useful for pets with tumors in places that are difficult to remove surgically, like the brain or nasal cavity. It is most effective for cancers that haven’t spread to other areas of the body.

Radiation can also be used to help relieve pain and other symptoms.

What Types of Tumors are Treated with Radiation?

Radiation therapy is commonly used for:

• Oral and nasal tumors
• Brain tumors
• Mast cell tumors
• Soft tissue sarcomas
• Bone tumors

It can also be helpful in cases where surgery isn’t an option due to the tumor’s location or if there is a chance that cancer cells were left behind after surgery.

How is Radiation Given?

If your vet recommends radiation therapy, they will explain how many treatments your pet will need and what to expect. A CT scan is usually required beforehand to create a detailed treatment plan specific to your pet’s tumor.

Each session requires your pet to be placed under brief anesthesia, so they stay still during treatment. As anesthesia is short-acting and pets typically recover quickly.

Are There Any Side Effects?

Side effects depend on the radiation dose and area being treated. Some pets may develop mild redness or irritation at the treated site, similar to a sunburn. In rare cases, more significant side effects may occur, but veterinarians take steps to minimize discomfort. Medications can help manage any pain or inflammation, and your veterinarian will work with you to ensure your pet remains comfortable throughout treatment.

Most side effects are temporary, and pets usually return to their normal activities soon after treatment is complete. Fur does not always grow back in the treatment site. When it does regrow, it sometimes grows back white in color.

Preparing for Treatment

• Your pet may need to fast (no food or water) the night before each session—your veterinarian will let you know if this applies.
• If your pet is regularly groomed, it may be best to schedule a grooming session before radiation begins, as bathing and trimming may not be allowed during treatment.

What to Expect After Treatment

Side effects, if any, may develop during or over one to two weeks after radiation therapy has been completed. Your veterinary team will guide you in managing any discomfort and adjust medications if needed. Follow-up exams will be scheduled to monitor healing and check for any signs of tumor regrowth.

Radiation therapy can significantly improve your pet’s quality of life, either by controlling the tumor or making them more comfortable. If your veterinarian recommends it, they will help you understand what to expect and how to provide the best care for your pet throughout the process.

Radiation therapy has come a long way in treating cancer in pets. Two advanced techniques, Stereotactic Radiation (SRT) and Intensity Modulated Radiation Therapy (IMRT), are making it possible to treat tumors with greater accuracy while reducing side effects. These treatments can improve both your pet’s quality of life and how long they live after diagnosis.

What is Stereotactic Radiation (SRT)?

SRT is a specialized targeted radiation treatment that delivers high doses of radiation to a tumor in just one to three sessions. The goal is to destroy cancer cells while limiting damage to nearby healthy tissue. This method uses multiple beams from different angles, making it a powerful and precise treatment option.

Which pets benefit from SRT? SRT is commonly used for:

• Brain and pituitary tumors
• Nasal tumors
• Spinal tumors
• Certain chest and abdominal tumors SRT is especially useful for pets who may not tolerate daily radiation sessions or anesthesia well.

What is Intensity Modulated Radiation Therapy (IMRT)?

IMRT works similarly to SRT but is delivered over multiple treatments instead of just a few. It directs radiation at the tumor from various angles, carefully adjusting the beam strength to minimize damage to healthy tissue. This means your pet can receive effective radiation treatment with fewer side effects.

Which tumors are treated with IMRT? IMRT is commonly used for:

• Nasal tumors
• Brain tumors
• Pituitary tumors
• Anal sac carcinomas
• Other tumors in sensitive areas where precision is important

Why Does My Pet Need Another CT Scan?

If your pet has already had a CT or MRI to diagnose their tumor, they may need another scan before radiation treatment. This second scan helps map out the tumor’s exact size, shape, and location so the radiation oncologist can target it as precisely as possible. Your pet will be placed in the same position for each session to ensure accuracy.

What Are the Side Effects?

One of the biggest advantages of IMRT and SRT is their ability to minimize side effects. Traditional radiation often damages surrounding healthy tissue, leading to irritation or burns. These newer treatments allow vets to focus radiation more precisely, reducing these risks.

Possible short-term side effects may include:

• Mild skin redness or irritation in the treated area
• Temporary discomfort, which can usually be managed with medications

Serious long-term side effects are rare, and your vet will discuss any risks before starting treatment.

Will My Pet Need Anesthesia?

Yes, but only for a short time. Pets must stay perfectly still during radiation treatment, so brief anesthesia is used to ensure accuracy. These anesthesia sessions are short and carefully monitored to keep your pet safe.

Your vet may recommend additional tests (such as bloodwork, X-rays, or ultrasounds) before starting treatment to ensure your pet is healthy enough for anesthesia.

How Can I Learn More About IMRT and SRT?

If your pet has been diagnosed with cancer and you’re considering advanced radiation therapy, schedule a consultation with a veterinary radiation oncologist. They will review your pet’s case, discuss treatment options, and help you decide the best course of action to give your pet the best quality of life possible.

Many dogs with lymphoma respond well to treatment, going into remission after just a few chemotherapy sessions. During remission, they often feel great—running, playing, and enjoying life as if they never had cancer. Unfortunately, lymphoma usually returns over time. While chemotherapy alone has been the standard treatment, survival times haven’t improved much in the past 20 years.

A newer approach combines chemotherapy with half-body radiation to help dogs stay in remission longer. Here’s how it works:

• First, chemotherapy is used to shrink the cancer and get the dog into remission.
• Then, the dog receives two sessions of half-body radiation, a low-dose treatment that helps target any remaining cancer cells.
• Finally, the dog completes a shortened chemotherapy plan to help keep cancer from coming back.

Some dogs experience side effects such as mild digestive upset or slight changes to their coat, but overall, they continue to feel good. Early results suggest that this combination treatment helps dogs stay in remission longer and live longer than with chemotherapy alone.

Strontium-90 is a type of radiation therapy used to treat small, surface-level tumors in pets. It is especially helpful for treating mast cell tumors in cats, certain skin cancers caused by sun exposure, and small mast cell tumors in dogs, like pugs. It can also provide relief for tumors under the tongue in cats and is a great option for pets with multiple small tumors.

One of the biggest advantages of Strontium-90 therapy is that it is quick and minimally invasive. Each treatment session takes less than ten minutes, and pets only need a brief anesthetic to keep them still. This makes it a great option for tumors in delicate areas, like the eyelids or cornea, where surgery might be difficult.

This treatment is an effective way to target small tumors while keeping the process as stress-free as possible for your pet.

Immunotherapy is a treatment that helps your pet’s own immune system fight cancer. It is used for certain types of cancer, including melanoma, lymphoma, hemangiosarcoma, kidney cancer, and multiple myeloma.

This treatment works by using special vaccines or injections that help the immune system recognize and attack cancer cells. One big benefit of immunotherapy is that it is usually gentler than chemotherapy and has fewer side effects.

When is Immunotherapy Used?

Immunotherapy works best when the body can recognize the tumor as something harmful. Scientists are still researching which cancers respond best to this type of treatment, but it has shown promising results in dogs and cats.

Which Cancers Can Be Treated with Immunotherapy?

One of the most common cancers treated with immunotherapy is melanoma. In fact, a groundbreaking melanoma vaccine was developed for pets, changing the way this cancer is treated. Researchers are also working on vaccines for other types of cancer.

How is Immunotherapy Given?

Most immunotherapy treatments are given through injections under the skin, similar to a vaccine. Some treatments involve a series of shots over time.

Are There Side Effects?

The most common side effects are mild and temporary. Some pets may feel tired or have a reduced appetite for a day or two, similar to having the flu. Serious side effects are rare.

How Should I Prepare for Treatment?

No special preparation is usually needed. Your vet will let you know if any precautions are necessary based on your pet’s specific condition.

What to Expect After Treatment?

Unlike some other treatments, immunotherapy does not always work immediately. It may take weeks or even months before you see results. Your vet will monitor your pet’s progress and adjust the treatment plan if needed.

For many pets, immunotherapy offers a safe and effective way to fight cancer while maintaining a good quality of life.