Vet Insights: Chemotherapy and Radiation Therapy for Dogs — What You Need to Know
Cancer treatment in dogs is determined by the type of cancer your pet has. Depending on the type of cancer, your veterinarian will recommend surgery, radiotherapy, chemotherapy, or a combination of these – these are the most common treatment methods for cancer patients.
Your vet needs to know the histopathological diagnosis, the stage of the cancer, your dog’s history, and your financial capabilities to determine the right treatment for your dog. We will discuss all of this in the following. In addition, defining goals and expectations for the treatment your dog is going to receive is also important.
Tumors that are in the growth phase, in the cell division phase, are more sensitive to chemotherapy. Therefore, if there are few dividing tumor cells, chemotherapy will be less effective. On the other hand, radiotherapy is applied when the tumor has occurred in an area that is difficult to reach for surgical removal, when it is desired to shrink the tumor before surgery, or after surgery to neutralize any remaining tumor cells.
In this article, you will learn about the differences between chemotherapy and radiotherapy in dogs, the different chemotherapy drugs and what types of cancer they are used for, what radiation therapy is used for and its side effects, the costs of cancer treatment, and much more.
Overview of Cancer Treatments in Dogs
The goal of cancer treatment in dogs is to eliminate or control it, improving quality of life and extending survival time. Treatment differs depending on the type of tumor, whether it is localized or has spread throughout the body (metastasized). It may include surgery, radiotherapy, chemotherapy, cryosurgery, or immunotherapy, which can be used alone or in combination.
1. Surgery
Surgery is the most common treatment option vets use for cancer. In cases where the cancer has not spread throughout the body, surgery can be curative. In cases where there are metastases or the tumor cannot be completely removed, surgery can be combined with chemotherapy or radiotherapy.
2. Chemotherapy
Chemotherapy drugs are sensitive to rapidly dividing cancer cells. This treatment method is usually used for systemic cancers such as leukemia and lymphoma. It is also used when metastases have developed or in combination with surgery. Depending on the selected drug and cancer type, chemotherapy may be administered intravenously (most common), orally, or injectable.
3. Radiotherapy
Radiation therapy generally uses high-energy X-rays to target cancer cells, destroying their genetic material. It can damage healthy tissue along with the cancerous tissue. However, the side effects are manageable, and the healthy cells repair themselves more easily.
It is used when surgery is not an option (for cancers located in the brain, nasal cavity, or spine) or when the goal is to shrink a tumor before surgery. It can also be used to kill any remaining cancer cells after partial surgical removal of the tumor or to relieve pain, especially in bone cancer. It is usually given in several sessions to see results.
4. Immunotherapy
Immunotherapy is a somewhat new treatment method that targets only abnormal cells while protecting healthy cells. This treatment method uses the dog's immune system to fight cancer.
5. Symptomatic Treatment
When no treatment method is possible, symptomatic treatment can help manage pain and secondary signs, improving the well-being of your dog.
The Importance of Understanding Chemotherapy and Radiation Therapy
With a basic understanding of chemotherapy and radiation therapy, you will be able to make informed and more confident decisions when your dog is diagnosed with cancer. While these treatments are common in veterinary oncology and can be extremely effective, they are often misunderstood, which happens due to a lack of information. Knowing what to expect when it comes to cancer treatment can reduce anxiety and help you prepare emotionally, practically, and financially.
In addition, good communication with your veterinarian can keep you calm and involved in your dog's care journey.
Understanding Chemotherapy in Dogs
What Is Chemotherapy for Dogs?
Chemotherapy is a type of cancer treatment that uses one or more chemicals (natural extracts or synthetic products) to stop the multiplication of cancer cells. This mechanism occurs either by destroying cancer cells or by stopping their division. The side effects that occur in humans (hair loss, vomiting, or general malaise) are not as prominent in pets. In other words, dogs tend to tolerate chemotherapy better than humans.
How Chemotherapy Works?
Chemotherapy drugs target and kill cancer cells that are actively dividing and multiplying – a process known as cell mitosis. Cancer cells tend to divide and multiply faster than most normal cells in the body. Chemotherapy interferes with and destroys the genetic material (DNA) inside the nucleus. This stops the cells from multiplying properly, leading to their death (apoptosis).
Although chemotherapy is effective for rapidly dividing cells, it can also affect healthy cells in the body, which is why side effects can occur.
Common Chemotherapy Drugs Used in Canine Cancer
Chemotherapy drugs can be used in three ways: oral, injectable, and infused. Examples of chemotherapy drugs in dogs and what cancers they are used for include:
1. Oral Drugs
Toceranib – used especially to treat mast cell tumors in dogs, but can also be used in other types of carcinomas. However, toceranib is not considered a chemotherapy drug but an anti-cancer medication because it works by blocking specific molecular pathways essential for cancer growth and not by killing cancer cells.
Prednisone – it is not a chemotherapy drug but a corticosteroid drug that can be prescribed by vets for lymphoma, leukemia, mast cell tumors, and brain tumors.
Chlorambucil – it is a chemotherapy drug, being the most effective drug evaluated for the treatment of chronic leukemia in pets. It can also be recommended in lymphoma or other types of cancer in dogs, such as mast cell tumor, soft tissue sarcoma, or different types of carcinoma.
Cyclophosphamide – this chemotherapy drug is usually administered in cancers like lymphomas, sarcomas, and carcinomas. It is often used in combination with other chemotherapy drugs for a better survival time.
Lomustine – it is a chemotherapy drug that is administered in cancers like mast cell tumors, histiocytic sarcoma, and relapsed lymphoma. Because this drug can penetrate the blood-brain barrier, it can also be used in treating brain and spinal cord cancers.
2. Injectable Drugs
Injectable chemotherapy drugs can be administered into the skin, into the muscle, or into the tumor.
L-asparaginase – this chemotherapy drug is an enzyme derived from E. coli and is designed to deplete tumor cells of the amino acid asparagine. While normal cells in the body need a small amount of asparagine that they can produce internally, cancer cells need massive amounts. Once cancer cells are deprived of this amino acid, they begin to die. It is used predominantly in lymphoma.
3. Intravenous (IV) infusions
Doxorubicin – this chemotherapy drug is administered intravenously slowly over approximately 10 minutes. Doxorubicin is cumulatively cardiotoxic, meaning there is a maximum amount of doxorubicin that a cancer patient can take in their lifetime before heart problems develop. In addition, adverse effects such as gastrointestinal upset are common and occur 2-5 days after administration. Dogs with liver problems may not respond well to treatment because doxorubicin is activated by the liver. Dog breeds, such as Australian shepherds and Long-haired whippets, are more prone to toxicity. Moreover, doxorubicin can be found in the pet’s urine for up to 21 days after administration. Therefore, any fecal matter, urine, or vomit should be handled with gloves to protect yourself because it is toxic to healthy cells. Doxorubicin is used to treat the following types of cancers: lymphoma, mammary gland carcinoma, thyroid cancer, sarcoma, osteosarcoma, and melanoma.
Epirubicin – a chemotherapy drug (a stereoisomer of doxorubicin) that is part of a multi-agent protocol for canine multicentric lymphoma. It can also be administered in histiocytic sarcoma, splenic hemangiosarcoma, various types of carcinomas, and lymphoma. It is administered slowly IV over 15-20 minutes. Most common side effects include vomiting, diarrhea, lethargy, and lack of appetite.
Carboplatin – a chemotherapy drug (a second-generation platinum antineoplastic agent) used by veterinarians in cancers such as osteosarcoma and hemangiosarcoma. It is administered slowly intravenously over 15-20 minutes. Side effects may include gastrointestinal upset, such as vomiting and diarrhea, and decreased appetite. Kidney problems and hair loss are rare. You should wear gloves when you clean your pet’s vomit, stool, or urine.
Cisplatin – it is a platinum-based chemotherapy drug (like carboplatin), being used in cancers such as osteosarcoma, melanomas, and different types of carcinomas. It is administered slowly intravenously, but it requires a generous amount of IV fluids after its administration.
Mitoxantrone – a chemotherapy drug often used in lymphoma and bladder cancer. It is administered slowly IV over 10-30 minutes. Common side effects include GI upset and loss of appetite.
Vinblastine – it is a chemotherapy drug (a vinca alkaloid) used for canine mast cell tumors and lymphoma. Common side effects may include anemia, lethargy, and GI upset.
Vincristine – it is a chemotherapy drug used primarily in canine lymphoma. Most common side effects include vomiting, diarrhea, and loss of appetite.
Safe Handling of Chemotherapy Drugs and Side Effects for Pet Owners
If you have a pet with cancer that is undergoing chemotherapy, you may be exposed to traces of the drugs or their waste through direct contact. Most chemotherapy drugs are excreted in the urine and feces over a period of 3-7 days. As previously mentioned, studies show that doxorubicin can be found in urine in low concentrations for up to 21 days after treatment, so keep this in mind if your pet is being treated with this medication. To minimize exposure, it is essential to follow safety guidelines. Here’s what you need to know:
- If your pet is on IV medication, handle their waste (vomit, urine, and feces) with gloves for up to 3 days and wash your hands after every contact.
- If they are on oral medication, handle their waste with gloves for 7 days, and wash your hands after every contact.
- Let your dog urinate and defecate in sunlit, low-traffic outdoor areas. You can use a low-flow hose to dilute their urine.
- Double-bag solid waste; clean surfaces with detergent and dilute bleach.
- If you or someone in your household got in contact with your dog’s waste, rinse with water immediately and wash with dish soap for at least 5 minutes. Consult your physician if needed.
- Wash soiled fabrics twice, separately from other laundry, preferably with bleach.
- Supervise their interaction with other pets and children to ensure they do not come into contact with your dog’s waste.
- Women who are trying to conceive, are breastfeeding, or are pregnant should not handle the pet’s waste or medication.
- If you are handling chemo drugs, always wear chemotherapy-rated gloves and wash your hands afterwards.
- Do not crush pills or open capsules.
- Do not store your dog’s chemo drugs next to your own medicine.
- Avoid storing your pets’ medication near food or in places where children and other pets have access.
Understanding Radiation Therapy in Dogs
What Is Radiation Therapy?
Radiation therapy is a treatment for cancer in pets, and it can be used for the following:
- Shrinking the tumor before surgery.
- Destroying cancer cells after surgical removal of the tumor.
- Slowing the growth of tumors in parts of the body where surgery is not possible (e.g., nose, brain, or bone).
Radiation therapy can be administered in a variety of cancers, such as:
- Bladder tumors
- Brain tumors
- Bone tumors
- Mast cell tumors MCT
- Soft tissue sarcomas
- Vaccine-associated sarcomas
- Lymphoma
- Nasal tumors
- Oral tumors
- Prostate tumors
- Perianal tumors
- Pituitary tumors
Multiple sessions are needed to see results. This therapy method involves high costs and is generally available in specialized veterinary hospitals.
Radiation therapy does not cause significant damage to the surrounding tissue and can help relieve pain.
The mechanism of action is to damage the DNA of cancer cells at high doses. The damaged cancer cells stop dividing and die, being then broken down and removed from the body.
Side effects of radiotherapy may include:
- Fatigue – some dogs may appear exhausted after treatment.
- Skin redness – the treated area may become red or swollen, or your pet may lose hair.
- Healthy tissue irritation – as mentioned earlier, radiotherapy can affect the surrounding healthy tissue without having a major impact on it.
Effectiveness and Expected Outcomes
Radiotherapy is most often used to relieve cancer symptoms and improve the dog's quality of life. For MCT, radiotherapy can be considered a remedy when used after surgical removal of the tumor – approximately 90% of patients live more than 2 years after treatment without signs of recurrence.
Chemotherapy vs. Radiotherapy: Cost Considerations and Financial Assistance
Cost of Chemotherapy For Dogs
Maybe you have wondered how much chemotherapy is for dogs. The cost of chemotherapy treatment varies depending on the type of cancer and the protocol used (single-agent or multi-agent protocol). Therefore, prices can range from $150 to $500-600 per treatment session. In addition, there will be additional costs for blood tests, imaging, biopsy, medications to improve symptoms (anti-nausea, pain medication, antibiotics, etc.), rechecks, and follow-up visits.
You can also opt for veterinary payment plans, pet insurance, or ask about alternative therapies.
Cost of Radiotherapy For Dogs
Radiotherapy is usually more expensive than chemotherapy. This is because they need specialized equipment, personnel, and facilities for the treatment. Therefore, consultation, CT scans, planning, etc., can cost up to $2000.
Given the fact that the treatment needs multiple sessions over weeks, the costs can get up to $10,000. There will also be additional costs for blood work, imaging, medications to improve symptoms, rechecks, follow-up visits, and anesthesia for each session (which is required for most pets).
You can also opt for veterinary payment plans, pet insurance, or ask about alternative therapies.
Alternative Therapies
Chemotherapy and radiation therapy are standard treatments for cancer in dogs. However, some pet owners prefer alternative or complementary therapies to support their dog's overall health, slow tumor growth, or manage side effects. Here are some of the most common options:
1. Holistic and Integrative Therapies
These therapies are used in combination with conventional treatments, along with chemotherapy or radiation therapy. As a result, acupuncture and massage therapy can be used to promote circulation, manage pain, increase appetite, and improve well-being.
2. Medicinal Mushrooms and Herbal Remedies
Some natural substances may support your dog’s immune system or have mild anti-tumor effects.
Turkey Tail Mushroom (Coriolus versicolor) – Contains polysaccharide-K PSK, shown to potentially extend survival in dogs with various types of cancer, especially hemangiosarcoma. Zumalka’s Coriolus (Turkey Tail formula is a natural supplement designed to support a healthy immune system and promote overall vitality in pets dealing with cancer. Rich in antioxidants and beneficial compounds, this mushroom-based product helps maintain normal cellular function and immune response, especially during times of stress or health challenges like chemo or radiation therapy.
Reishi mushroom (Ganoderma lucidum) – According to studies, Reishi mushrooms can suppress protein synthesis and tumor growth. Zumalka’s Reishi formula is a natural supplement rich in antioxidants, traditionally used to support immune system health and help maintain normal cellular function in pets fighting cancer or tumors in the colon or skin. This mushroom also promotes liver health and supports the body’s natural defenses during times of physical stress, like chemotherapy or radiotherapy. Its adaptogenic and wellness-supporting properties make it a valuable addition to your pet’s daily routine.
Shiitake mushroom (Lentinula edodes) – It can enhance immune responses in cancer therapy. Studies show that shiitake was effective in extending survival in patients with stomach, colorectal, pancreatic, and liver cancers. Zumalka’s SHIITAKE product helps support a healthy immune system and liver function in pets battling tumors in the colon, stomach, pancreas, and liver. Rich in essential nutrients like vitamins B2 and B12, this mushroom promotes overall vitality and immune resilience. It also offers natural compounds that contribute to the body’s defense against environmental stressors, helping your pet feel their best.
Astragalus, Milk Thistle, and Curcumin (from turmeric) – These supplements can be used for immune support and anti-inflammatory effects. Moreover, they can also help support the liver during chemotherapy and radiotherapy. Zumalka’s HEPATOPET product is an excellent liver tonic for pets. It contains all of these three ingredients and more.
CBD Oil (Cannabidiol) – Can be used to reduce pain, inflammation, and anxiety. It was also shown that it can have anticancer effects.
Always consult a holistic vet before using any natural remedies or products.
3. Other Natural Remedies
Another product that can support your dog's immune system and body while fighting cancer is PIPTOPET. This natural product is a mother tincture that contains Fomitopsis betulina, a mushroom well-known for its multiple health benefits. Studies conducted on dogs, monkeys, and mice have highlighted the following properties: anti-inflammatory, antibacterial, antiviral, antioxidant, and anticancer.
To enhance PIPTOPET’s benefits, you can use it in combination with TONICPET #4, #5, #7, and #10.
TONICPET #4 supports your dog’s body's natural immune response and promotes healthy oxygen circulation.
TONICPET #5 promotes good blood flow and functioning of all your dog’s body systems.
TONICPET #7 supports your dog’s body's natural immune response and promotes healthy oxygen circulation into the deeper layers of the skin.
TONICPET #10 supports balanced pH levels in your pet’s body and aids in healthy digestive function. Cancer cells like acidic environments, and this product helps create a more balanced environment to discourage cancer growth.
By combining these products, you provide your dog with a powerful, natural remedy to boost their immune system and overall health.
4. Diet and Nutritional Support
A high-protein, low-carb diet may slow your dog’s cancer growth by limiting their sugar intake. Omega-3 fatty acids (like fish oil) offer anti-inflammatory benefits and support their coat and weight health. For more information, talk to a veterinary nutritionist.
5. Stress Reduction and Environmental Support
A calm and stable environment can help strengthen your dog's immune system. Therefore, provide them with play, gentle exercise, routines, and affection. All of these will contribute to their emotional well-being during treatment.
While alternative and complementary therapies can be helpful, especially when you want a gentler approach to your dog's cancer, they are not a substitute for chemotherapy or radiation therapy. However, they can work well alongside them and improve your dog's quality of life and possibly tolerance to treatment.
Frequently Asked Questions (FAQs)
Is it worth giving a dog chemo?
Chemotherapy is a method of treating cancer in dogs that aims to improve your pet's quality of life and increase their life expectancy. So, if the chemotherapy treatment prescribed by your vet is effective for your dog's type of cancer, it's worth a try. Talk to your veterinarian about any questions you have about your dog's cancer or treatment.
What is the life expectancy of a dog on chemotherapy?
The life expectancy of a dog undergoing chemotherapy depends on several factors: the type of cancer, the stage of the cancer (whether it has spread throughout the body or not), your dog's general health, and their response to treatment. In addition, it also matters whether your dog is undergoing treatment with chemotherapy drugs alone or if it is combined with surgery or radiation therapy. As a result, dogs that have undergone surgery followed by chemotherapy have a longer life expectancy than those that undergo chemotherapy alone. In general, the life expectancy for dogs undergoing chemotherapy is up to one year from diagnosis.
How successful is chemotherapy in dogs?
Chemotherapy can also extend your dog's quality of life, not just the length of time. So, unlike chemotherapy in humans, which has severe side effects that can reduce quality of life, it has fewer side effects in dogs. The success of chemotherapy depends on several factors: the type of cancer being treated, how early it was detected, and how well your dog responds to treatment.
What is the average cost of chemotherapy for a dog?
The cost of chemotherapy in dogs can vary significantly depending on several factors: geographic location (chemotherapy is more expensive in the US than in Europe, for example), type of cancer, and treatment protocol (single or multi-agent protocol). In the USA, a full course of chemotherapy can cost around $3,000-$6,000 (around $150-$600 per treatment session). To this cost must be added the additional costs for laboratory tests, other medications, imaging tests, rechecks, and follow-ups.
Is chemotherapy worth it for dogs?
Yes, chemotherapy can be worthwhile for dogs, especially when the goal is to improve their quality of life. Chemotherapy in pets has few side effects and is not as aggressive, unlike chemotherapy in humans. The decision depends on your dog's age, health status, type of cancer, and your emotional and financial readiness.
How much does chemo cost for a dog?
A full course of chemotherapy can cost up to $6,000, with each treatment session costing between $150 and $600. To these expenses, laboratory tests, imaging, other medications, rechecks, and follow-ups can also be added. Additionally, the total cost can vary depending on your geographic location, type of cancer, and treatment plan. So, talk to your veterinarian about the best treatment options.
How to afford dog chemo?
If you can’t afford chemotherapy for your dog, you can opt for: payment plans – many vet clinics offer financial options; pet insurance – some plans cover cancer treatments; CareCredit – it can cover veterinary expenses; nonprofits; university veterinary schools – they often offer low-cost treatments or clinical trials.
What is the success rate of chemotherapy in dogs?
The success of chemotherapy depends on factors such as the type of cancer, its stage, and your dog's overall health. As a result, for lymphoma, the remission rate is 70-90%, with dogs living about a year from diagnosis. In bone cancer, dogs treated with chemotherapy after amputation have a survival time of about a year from diagnosis. In the case of mast cell tumors, dogs that undergo chemotherapy (often because surgery is not possible) have an average survival time of about 1-2 years. Dogs with visceral hemangiosarcoma, which is a very aggressive type of cancer, have a survival time of about 6-9 months with surgery and chemotherapy.
How much does it cost to put a dog through chemo?
The cost of chemotherapy for dogs diagnosed with cancer can reach $6,000, not including lab tests, imaging, supportive medications, and veterinary visits. A single treatment session costs between $150 and $600.
How do you pay for chemotherapy for dogs?
If you cannot afford the chemotherapy costs for your dog, there are other payment options and financial plans you can try, such as payment plans, pet insurance, CareCredit, nonprofits, university veterinary schools, and clinical trials.
Is it worth putting a dog through chemotherapy?
Putting a dog through chemotherapy can improve their well-being and give them some time. It has fewer and less severe side effects compared to chemotherapy in humans. However, it depends on the type of cancer, its stage, and your dog’s overall health.
How expensive is chemotherapy for dogs?
A full course of treatment can cost up to $6,000. However, several factors must be considered, including geographic location, the type and stage of cancer, the complexity of treatment (single or multi-agent protocol), and your dog's overall health. In addition, veterinary visits, blood work, imaging, and supportive medications will increase this cost.
Is radiation therapy worth it for dogs?
As with chemotherapy, radiation therapy is worth it for your dog, but it depends on several factors such as location, type of cancer, and your goal: curative or palliative. Radiation therapy is used for pain relief, inoperable tumors, or to extend your pet’s life. It has fewer side effects compared to chemotherapy and is well tolerated by dogs. Radiotherapy is effective for bone, nasal, or brain cancers that are usually inoperable.
What is the success rate of radiation therapy in dogs?
Radiation therapy in dogs can be very effective. It often improves the quality of life and can extend a dog’s survival by several months or even years. Combined with surgery, a dog with cancer can live for over 2 years, with about 90% of dogs responding to treatment. For palliative purposes, it helps relieve pain in 74-96% of dogs, especially those with bone cancer.
How much does radiation therapy cost for a dog?
Costs range from $3,000 to $10,000+, and it requires multiple sessions under anesthesia. It’s a good option when surgery isn’t possible or if you're aiming to improve your dog’s quality of life. To this price, blood tests, other medications, imaging, and veterinary visits can also be added.
Is radiation therapy in dogs painful?
Radiation therapy is usually not a painful treatment. In addition, dogs are under light anesthesia during treatment, so they won't feel anything. However, it can have mild, manageable side effects at the level of the skin, such as local irritation or hair loss. Furthermore, radiation therapy is often used to relieve pain, especially in cases such as bone cancer, so many dogs feel better after treatment.
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