Palliative treatment of Canine Osteosarcoma using Samarium-153 Osteosarcoma is a malignant disease of bone often seen in large and giant breed canines. Unfortunately it has a very poor prognosis because approximately 90% of dogs with osteosarcoma are thought to have micro-metastatic disease at the time of diagnosis. Therefore the main goal of treatment is to relieve the pain associated with the tumour and, if possible, slow down the progression of the primary tumour and metastatic disease.
A promising option for canine osteosarcoma that we offer at the Gladesville Veterinary Nuclear Centre is treatment using Samarium 153. It is important to note that there are several “treatment” options available for osteosarcoma and the final decision should be based on each individual case such as: size, general health, degree of lameness, cancer sites and other medical problems of the dog.
Samarium-153 is a “bone-seeking” radio-isotope which emits both gamma and beta rays. The dual radiation characteristic of Samarium is important in that the gamma ray activity allows the use of scintigraphy to track uptake of the radioisotope and the beta ray activity gives it the ability to cause localised tissue destruction.
When injected in conjunction with a bone-seeking pharmaceutical, it is selectively taken up by rapidly metabolising bone cells as are found in steosarcoma. Thus at a cellular level a dose of radiation is given to the tumour itself.
Use in human medicine Samarium has most often been used in human patients for treatment of painful bone metastases from malignancies such as rostatic and breast carcinoma.
It has been shown to reduce the requirement for analgesics in these patients and is considered to be an effective palliative measure to relieve pain.
Generally, pain relief has occurred within one week of administration.