What is Osteosarcoma?

Please understand the following information is offered as a courtesy and is not intended to provide a diagnosis or medical recommendation for your pet.

Osteosarcoma is the most common primary bone tumor in dogs. Once your pet has been diagnosed with this disease, you clinician will discuss how we manage osteosarcoma from two different perspectives. The first is by addressing the local disease, determining which treatment is best for the primary tumor. Such treatment options include surgery, such as an amputation of limb spare, or radiation therapy (see other handouts). Once the local disease is well managed, it is important to continue treatment to help fight the spread of disease (metastasis) throughout your pet’s body. Chemotherapy is the best way to do this, and can aid in prolonging your pet’s life. One of the most common areas this kind of cancer spreads to is the lungs. The best way for your clinician to monitor the spread of disease is by recommending radiographs (x-rays) for your pet’s lungs every few months.

Once you and your clinician have determined that chemotherapy is appropriate for your pet, the next step is to decide which protocol (treatment plan) is the best. There are several different chemotherapy options to choose from. When considering these options, several points should be taken into account. 

Toxicity: How sick will the drugs make your pet?
Although we try to minimize toxicity and side effects from chemotherapy as much as possible, we are unable to predict which dogs will get sick. Each pet responds to the chemotherapy drugs differently. The most common side effect we generally see is GI toxicity. These symptoms include nausea, vomiting or diarrhea. Fortunately, the majority of these symptoms can be controlled with oral medications at home. Another side effect is a low white blood cell count, creating a weaker immune system and making the pet more susceptible to infection. We monitor this by checking complete blood cell counts (CBC) before each chemotherapy treatment. If the white blood counts are low, we will delay treatment until the pet’s body is strong enough to withstand more chemotherapy. 

Your Dog’s General Health
Each patient is different and not every drug is right for your pet. Your clinician will go over risks and benefits of each protocol for your pet, and together you will decide what is best. Pre-existing health problems may alter our ability to use certain chemotherapeutic drugs. 

Time Commitment
Generally, the more intensive the protocol, the more time you will invest in the care of your dog. The frequency of office visits and blood work varies among the different drug options. 

Cost
Protocols that combine chemotherapeutic agents are often more effective, but also more expensive than single agent protocols. Costs such as physical exams, blood tests, medications and potential costs of toxicity should be considered. Please refer to individual protocol handouts for current cost estimates. 

Treatment Options
While treating your pet, our goal is to achieve an acceptable quality of life for your pet by maximizing tumor response and minimizing toxicity. Listed below are several chemotherapy protocols. Your pet’s clinician will explain these in detail and help you choose the approach that is best for both you and your pet. 

Adriamycin
In the primary study of Adriamycin (Duxorubicin) for the treatment of bone cancer, average survival time was approximately one year. The protocol consists of five treatments two or three weeks apart and each visit costs approximately $140 -$170 (cost includes a physical exam, blood work, drug costs and drug administration fees). This drug can cause GI toxicity, so we will send you home with medications to help control the nausea and diarrhea. In order for your clinician to monitor how the Adriamycin affects your pet’s bone marrow, your pet will need a CBC performed one week after the first treatment is given. This can be done at CSU or at your referring veterinarian’s office.

Although this drug is quiet effective, it has been shown to cause cardiomyopathy (heart disease) in patients who receive high or repeated doses. Therefore, we limit the amount of Adriamycin each dog can receive, and we do not recommend using this drug for patients with pre-existing heart conditions. For patients who are suspected to have heart problems or breeds that are predisposed to develop heart disease, an evaluation of the heart (an echocardiogram) is recommended (approximate cost is $200). 

Cisplatin
Cisplatin is the most thoroughly studied chemotherapeutic agent for bone cancer, studies show that this drug results in an average survival time of 1 year. Although Cisplatin is quiet effective, a significant side effect of this drug is renal (kidney) toxicity. In order to protect your dog’s kidneys, we will give your pet IV fluids several hours before and after treatment. Occasionally, your pet will have to stay overnight for this fluid therapy. Treatments are administered once every three weeks for a total of four treatments, and each visit costs approximately $500 - $600 (cost includes physical exam, CBC, Kidney tests, IV fluids, drug costs and intensive care). 

Carbolatin
Carbolated is similar in action to Cisplatin, but does not cause renal toxicity. The average survival time is less than one year. It comes highly recommended for dogs that are unable to receive other chemotherapeutic agents due to heart or kidney problems. This drug is administered once every three weeks for five treatments. Costs are approximately $800 - $1700.00 (depending on body weight) per visit. The cost includes physical exam, CBC, drug costs, and drug administration. 

Adriamycin/Cisplatin
As with the Adriamycin/Carbolatin protocol, this protocol takes place over two days and required that your pet stay in the hospital for one night. On the first day, your pet will be given Cisplatin along with IV fluids to protect the kidneys. IV fluids will be given all night long. On the second day, the fluids will be stopped and your pet will receive Adriamycin and be ready to home later that day. This protocol takes place every 3 weeks for a total of four treatments. Each two-day visit will cost approximately $700.00 - $800.00 and a CBC will be recommended seven to ten days after treatment. Average survival time is ? year, and toxicity can be significant.

This is a general overview of treatment options. Please read specific handouts for further details on these protocols.