Depending upon the grade, stage and type of cancer, your team will recommend one or a combination of treatment options. Multiple treatment options that combine surgery, radiation and chemotherapy are the rule rather than the exception. This is because the treatment of cancer in animals has become as sophisticated and successful as the treatment of cancer in humans.
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.
In veterinary medicine, radiation therapy was first attempted at the beginning of the twentieth century. During the past 50 years, major advances have been made. The use of histopathology, MRI, and CT scans has resulted in more accurate diagnosis of the type and location of tumors. Newer radiation equipment and new technology such as intensity modulated radiation therapy (IMRT) has allowed the radiation to be tailored to the individual patient's tumor with more and more accuracy, so that normal tissues around the tumor can be spared. This has increased the effectiveness and decreased the side effects and risks of radiation therapy.
Stereotactic radiation (SRT) and Intensity Modulated Radiation Therapy (IMRT) are becoming more readily available for animals. In the past, traditional radiation therapy to treat cancer in pets would usually result in significant side effects and many owners would decide not to pursue treatment because of this. IMRT and SRT are changing the way that we are able to treat cancer in pets, and they have great potential to improve both your pet’s quality and quantity of life. The Veterinary Cancer Center is pleased to be able to offer these treatments for pets with cancer.
Stereotactic radiation, also known as stereotactic radiosurgery, involves delivering a small number of large radiation doses to the tumor, in the hope of causing maximal tumor damage while limiting the dose to the normal tissues. Usually this is done in 1 to 3 treatments over a short period of time. With stereotactic radiation, a large number of beams are directed at your pet from all different angles and the shape of the radiation beam is changed, during treatment, to deliver radiation where it is needed most.
What tumors can be treated with SRT?
SRT can be used to treat a variety of tumors, including brain tumors, pituitary tumors, nasal tumors and other tumors involving the head and neck. It also can be used to treat tumors of the spine and some parts of the abdomen or chest. It can be used for pets when daily visits and anesthesia may be too dangerous.
What is Intensity Modulated Radiation Therapy or IMRT?
IMRT uses the same technology as SRT with a large number of beams to attack the tumor from all angles while each beam is shaped to precisely deliver the radiation where it needs to be directed. With IMRT similar doses are used that have been used for conventional radiation in the past. However, IMRT allows the dose of radiation to be targeted at the tumor, with great precision, to avoid treatment of the normal tissues. This allows the same or higher doses of radiation to be delivered directly to the tumor, with fewer side effects for your pet.
What tumors can be treated with IMRT? IMRT can be used to effectively treat nasal tumors, brain tumors, pituitary tumors anal sac carcinomas and a number of other tumors. In any location where radiation side effects might be a problem, IMRT can be used to help minimize them.
Why does my pet need another CT scan for treatment?
If your pet with cancer has already had a CT scan or an MRI to diagnose their tumor, they may need a second CT scan for radiation planning. The first CT or MRI is useful to help determine where your pet’s tumor is, but the radiation planning CT is necessary for your pet for treatment. With newer radiation technology, as we tighten, or conform, the does tightly around the tumor, it is critical that your radiation oncologist know exactly where they are treating. Therefore a second CT scan is often necessary for this. Usually, your pet will be placed in a positioning device such as a bite block and/or vacuum bag, to make sure that they are positioned the exact same way for the CT scan and for each treatment. The CT scan requires a short anesthesia, but it is well worth it to make sure that your pet is receiving the most accurate delivery of their radiation dose.
What are the potential side effects for my pet?
One of the main benefits of IMRT and Stereotactic radiation is that they can minimize the side effects from radiation, making treatment much more tolerable for you and your pet. With traditional radiation treatments there are often significant side effects in the local area from damage caused by the radiation. With IMRT and SRT the dose of radiation can be targeted very tight around the tumor, using a radiation plan that is customized for your pet, minimizing the dose of radiation that is given to your pet’s normal tissues. In some areas, such as the head or pelvis, this is critical for avoiding severe side effects. For example, traditional conformal radiation for nasal tumors in dogs usually results in severe inflammation and burning in the mouth, around the eyes and the skin of the face.
There is also a risk of a severe, long-term complication in the eyes, the brain or the local bones. With IMRT and SRT, the dose of radiation to these structures can be minimized, limiting side effects to small areas. This means a better quality of life for your pet. With any type of radiation treatment a brief anesthesia is usually required. This anesthesia is needed to make sure that your pet stays perfectly still for each treatment. It is usually a short anesthesia, and your pet is monitored very closely while under anesthesia.
Even when radiation patients have anesthesia every day, the risk of significant complications is very low. Your radiation oncologist will evaluate your pet to make sure that they are likely to handle the anesthesia well and may recommend additional staging tests, such as radiographs, ultrasound, an echocardiogram, bloodwork and or urinalysis to help make sure that your pet is a healthy candidate for anesthesia. Another potential benefit of SRT is that it may be able to limit the number of treatments that your pet will need, minimizing the risk of anesthesia complications.
How can I find out more about IMRT or SRT for my pet?
Most dogs with lymphoma will go into remission after only a few treatments and they will often stay in remission for months. During this time, aside from having to come to see the oncologist for treatment, their quality of life is often very good. Once they get into remission owners often report that they are running, playing or just living their normal life as if they never had cancer. Unfortunately, almost all of these pets will eventually come out of remission and succumb to their disease. In the past twenty years there has been little to no improvement in the remission and survival times with chemotherapy alone. With this protocol, dogs are first treated with chemotherapy to get them into remission and this is followed by two treatments of half body radiation.Then a low dose rate is used, meaning that dogs develop almost no side effects from the treatment. They can get some changes to their hair coat and some intestinal upset, but otherwise they are typically fine. Most dogs will then go on to complete a shortened chemotherapy protocol. Initial results suggest that by combining radiation therapy with chemotherapy in this way dogs are in remission longer and are living longer with lymphoma.
Strontium – 90 probes have been used to treat small superficial tumors, including mast cell tumors in cats, solar induced squamous cell carcinomas in cats, small mast cell tumors in some dogs like pugs. It may be beneficial in palliative treatment of squamous cell carcinoma under the tongue in cats. It is great for treating pets with multiple tumors, because each treatment is usually less than ten minutes, and requires only a short anesthetic episode. For pets with multiple tumors it allows us to treat all of their tumors in one, shorter anesthesia. Also, it can be very helpful for treating eyelid tumors or corneal tumors, which are often very difficult to remove with surgery.
The Veterinary Cancer Center (The VCC) and Animal Clinical Investigation (ACI) are always looking for the best ways to diagnose and treat cancer in animals. Sometimes, the best ways are still unknown to science. Because of this, The VCC and ACI have partnered to create a Clinical Trials Center – the first of its kind – where new ways of treating and diagnosing cancer are evaluated. For more information on our current trials please click here...
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.
Under what conditions is Immunotherapy used?
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.
Which tumors are commonly treated with Immunotherapy therapy?
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.
How is Immunotherapy administered?
Subcutaneous methods consist of administration through subcutaneous routes, i.e., injections as well as infusions over time.
Are there any side effects?
The main side effects of this type of therapy are “flu-like” symptoms of malaise and loss of appetite.
How Should I prepare for treatment?
Typically, no preparation is necessary for this type of treatment.
What should I expect after 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.