[Primary spinal osteosarcomas].

Abstract

The rarity of primary osteosarcoma of the spine led us to index the 66 reported cases published in literature. From this analysis a difference was found between spinal osteosarcoma and osteosarcoma of the extremities. Tumors of the spine appear to be two times more frequent in the male population in their thirties. The average period between the beginning of the symptoms and the first consultation is seven months. Back pain is permanent and localized to the affected vertebra. In 80 percent of the cases, neurological symptoms already exist at the stage of the diagnosis. Magnetic resonance imaging (MRI), computed tomography and standard X-ray remain complementary in the morphological analysis of this tumor. All the aspects from the lytic to sclerotic forms are noted, although the lytic form is common. Among spinal osteosarcoma, the lumbar vertebrae are the most frequently affected. Diagnosis can only be established by pathology, even though this may also lead to some errors. In all the reported cases surgery is used, but carcinological methodology is not possible and a complete removal of affected tissue is difficult, with this being achieved in only a quarter of the cases. Radiation therapy, when used, requires doses of 70 Gy to 80 Gy without any certitude of controlling the tumour and with high risks of post-radiation complications. Chemotherapy on its own, despite the use of high-dose methotrexate, only has a temporary effect due to partial action on the primary center. Twenty years ago, only twenty percent of all patients suffering from osteosarcoma lived beyond two years, with worse prognosis for spinal osteogenic sarcoma. Today, the therapeutic approach for spinal tumors uses techniques developed in the treatment of osteosarcoma of the extremities, which can now expect more than seventy percent of all patients to live beyond five years. Present day methods recommend a rapid confirmation of the diagnosis, and then a neoadjuvant chemotherapy followed by surgery to remove all the affected area. This strategy allows an evaluation of the tumor chemosensitivity and to adapt the treatment in consequence. The latest results of this treatment on spinal osteosarcoma appear to be encouraging.