Dr. Jeffrey Philibert
Treatments for osteosarcoma may include the following: Surgery. The most common approach to the treatment of osteosarcoma involves removal of the tumor en bloc, which means bone along with normal surrounding tissues. Because osteosarcoma most commonly affects the limbs, amputation of the affected limb is usually the primary treatment. This is the best means of removing the cancer and it will typically provide relief from pain caused by the cancer. However, it is truly only palliative (pain relieving), because survival is not enhanced by performing amputation alone. Survival with amputation alone in dogs is in the range of four to six months on average.
Amputation may seem like a drastic measure, and you may question your dog's ability to deal with such a surgery. However, most animals do very well on three legs and the degree of pain associated with the surgery is minimal compared to the pain that they have experienced with the tumor. There is a period of recovery necessary after a limb amputation. Most animals spend at least one postoperative day in the hospital. Narcotic pain medications and fluid supportive care are often given. After your pet is released from the hospital, you will need to restrict activity severely until the surgical site heals and the sutures/staples are removed, usually 10 to 14 days after surgery. During this time your pet should not jump, play or climb stairs unattended. You will also need to keep the surgical site clean and dry.
Most animals go home on some form of oral pain medication, at the least, an anti-inflammatory aspirin-like drug, but they may also be given a narcotic pain patch. Address any questions that you have about your pet during the post-operative period with your veterinarian as soon as possible. Once healing has occurred, your pet can gradually return to normal exercise. It is surprising to many owners, but animals frequently feel so much better after the amputation that they are up and around and acting normal within two to three days after surgery.
Chemotherapy. Because of the highly metastatic nature of osteosarcoma, amputation alone is not sufficient to prolong survival substantially. Chemotherapy is usually prescribed in the post-operative period once healing has occurred and the sutures/staples have been removed. These drugs are given as intravenous injections in the leg, and typically follow a set schedule of being given every three weeks for a total of four to six doses. Many different types of chemotherapy drugs are available, and your veterinarian may wish to refer you to a veterinary oncologist in your area who can advise you on treatment options. The most commonly utilized drugs are cisplatin, carboplatin and adriamycin.
Every oncologist has a preference and may pick certain drugs or combinations based on your pet's general health and the appearance of the tumor. All of these treatments have about the same impact on prolonging survival, an average of about 10 to 12 months from diagnosis. Common side effects include a decrease in your pet's white blood cell count approximately seven to ten days after each treatment, nausea, vomiting and/or diarrhea. Each of these drugs also has unique side effects, which your oncologist will discuss with you, depending on the drug chosen for your pet.
Radiation therapy. This is a type of treatment in which a beam of radiation is directed at the tumor to kill the cells, and usually results in pain relief. It is a highly specialized treatment and is available only in some referral veterinary centers for select cases. It may be worth considering if your dog has existing conditions that disqualify him for amputation or if there is already evidence of metastasis. It typically involves multiple treatments given over a three-week period. Though it often results in pain relief, it seldom prolongs survival substantially, and the average survival time is still six months. Chemotherapy can be administered in conjunction with the radiation and may serve to control metastatic disease. Your dog will usually not experience any adverse side effects from this treatment, unlike what is typically associated with radiation therapy in people. The oncologist or radiation oncologist prescribing these treatments will discuss further details with you.
Pain medication. If you choose not to pursue any of the above treatments, the administration of both narcotic and non-narcotic anti-inflammatory medication can help in making your dog more comfortable for a period of time.
Limb-sparing surgery. This is a highly-specialized type of surgery where the bone containing the tumor is removed and replaced by a donor bone. This surgery is technically demanding and is available only at a limited number of veterinary surgical referral centers where there are surgeons trained to perform such surgeries and where a bone bank is available. It is most useful for very large- or giant-breed dogs whose ability to walk after an amputation may be questionable. If you feel your pet may be a candidate, the oncologist in your area can inform you of the pros and cons of this procedure and provide you the names of the centers that perform this procedure.