TYPES OF TUMORS

Most of the primary bone tumors in dogs is evil, and approximately 85% of them are Osteosarcomas.

They are tumors highly aggressive, characterized by invasion and local destruction and distant metástases (they disperse for other organs). Osteosarcoma usually affects the skeleton apendicular (members) of dogs of big races to giants, but it can also happen in the axial skeleton (skull, ribs, vertebrae, pelvis) that is the more common primary place in smaller dogs. Other bone tumors include condrosarcoma, fibrosarcoma, hemangiosarcoma, liposarcoma, multiple myeloma and metástases of bone tumors. The biological behavior, the prognostic and the treatment of these tumors depend on the type of the tumor, of the primary location and of the extension of the disease (phase). This way, several tests diagnoses as x-rays, blood test and a biopsy are demanded to determine the most appropriate treatment.

Clinical signs:

The clinical signs associated with a bone tumor can be inespecíficos and they depend at the primary place. The tumors in the members frequently cause several claudicação degrees (limping) and pain; besides, an increase of firm volume can be evident with the development of the tumor. The pain can cause other problems as irritability, aggression, appetite loss, weight loss, wailings, cry, insomnia and reluctance to exercise. Bone tumors out of the members they can seem initially as a solid and firm mass. Other clinical signs can vary and they depend at the primary place and of the involvement of the underlying structures.

Diagnosis and Evaluation:

The initial evaluation of a dog with suspicion of bone tumor, frequently includes: a complete physical exam, blood tests, x-rays of the primary place and of the lungs and a biopsy. The biopsy can be incisional or excisional. A biopsy incisional is only executed for diagnosis. A small sample of the tumor is removed to determine the specific type of the tumor. A biopsy excisional involves the total removal of the tumor, so much for the diagnosis as also with therapeutic purposes. The evaluation is important for two reasons: it is necessary to determine the tumor type and extension of the cancer, but it should also provide to the doctor a relative information to the general health of the animal and to identify the medical and muscle-skeletal problems simultaneously, all this to guide the recommendations of the treatment. Treatment of primary bone tumors:

As dictated above, the treatment recommendations for bone tumors depend on multiples factors: a complete physical exam and the evaluations above can be necessary to determine the most appropriate and necessary treatment for each dog. Being considered that Osteosarcoma is without a doubt the type of more common tumor, the discussion on the treatment will focus Osteosarcoma exclusively.

We frequently classified Osteosarcomas as apendicular or axial, because the location of the tumor can have implications so much for the surgical approach as well as for the biological behavior of the tumor, what requests different treatments.

The Osteosarcoma apendicular (members) it frequently causes claudicação and it hurts because of the invasion and of the destruction of the normal bone and of the periósteo (that are sensitive structures around of the affected bone). These tumors are also highly metastáticos (they are disseminated probably like this for other organs), and the animal with Osteosarcoma apendicular will usually live for 4 to 6 months if it be only treated with the surgery.

The surgery in VHUP usually involves the amputation of the affected member, but procedures of preservation of the member can be an option in selected cases. The surgery is for two purposes: it removes the primary tumor, what is necessary for the control of the cancer, and it also removes the pain source, could improve like this drastically the patient's quality of life.

The cause more common of the death it is for lung metástase. For that reason, the systemic chemotherapy is recommended for dogs with Osteosarcoma apendicular. It is unlikely that the chemotherapy cures most of the dogs with Osteosarcoma, but it can provide a sobrevida with good quality. We recommended now to use a combination of 2 different drugs: Doxorubicina and Cisplatina or Carboplatina.

Most of the dogs tolerates this chemotherapy well, with limited side effects and moderate as reduced appetite, nauseas, occasional vomits and diarrhea during some days. Minus than 5% of the dogs will present severe side effects, with threatening life risks, they request hospitalization and intensive cares. If the side effects in his/her dog are severe and they assume compromising of the quality of life, the dosages of these drugs should be reduced in the subsequent treatments. The common sobrevida in dogs with Osteosarcoma, treaties with surgery and chemotherapy, it is of approximately 1 year.

Axial Osteosarcoma is frequently diagnosed as a firm and solid mass. Other clinical signs vary and they depend on the location of the tumor and the involvement of the adjacent normal fabrics. Due to location of most of Osteosarcomas of the axial type, the surgical removal completes is not possible frequently. Microscopic cells of the tumor can be back and, being like this, it is probable that the tumor appears periodically at the same place. The common sobrevida in dogs with axial Osteosarcoma is from 4 to 5 months, and the cause more common of failure of the treatment it is the recurrence of the tumor in the place. Being like this the treatment to proceed is addressed for a better control place of the tumor, and the radiotherapy is a reasonable choice. There are limited information now as for the effect of the supporting radiotherapy in dogs with axial Osteosarcoma. The potential metastático of this Osteosarcoma varies, and depending on the location, the chemotherapy well can be indicated in some cases.

These are the general guidelines of the treatment of dogs with Osteosarcoma. Besides, they could be suggested palliative measures for dogs that are not framed in none of these options by several factors. A palliative treatment is to relieve the pain and the symptoms of the tumor, and it can involve the use of types different from medicines against the pain and/or some high radiotherapy doses. Such treatments can help to control the pain in the dogs with Osteosarcoma, giving to the proprietor and his/her dog, an additional time of coexistence, with good quality.

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