A prospective observational study on the disease course in children, adolescents, and adults with osteosarcomas and biologically related bone sarcomas

Osteosarcomas are rare malignant bone tumors that most commonly occur in adolescents and young adults. They often develop in the long bones, such as the thigh or upper arm, and in many cases grow rapidly and aggressively. In the early stages of the disease, micrometastases—tiny distant colonies of cancer cells in other organs—may already be present, which cannot be detected by routine diagnostic procedures. Typical symptoms include pain that is not related to physical activity. Swelling and limited mobility are also common.

Standard treatment involves surgical removal of the tumor and any metastases that may be present. For osteosarcomas with a high potential for metastasis (high-grade osteosarcomas), chemotherapy may also be used before and after surgery. The introduction of chemotherapy has improved treatment outcomes. Nevertheless, the prognosis for these diseases has stagnated in recent years, and the biological behavior of the tumors remains poorly understood.

The goal of the COSS Registry is to systematically collect data on these diseases in order to gain new insights into them and to lay the groundwork for further studies. To this end, a retrospective analysis of the data (past disease course) and prospective follow-up of patients (recording of the further course during routine medical examinations) are conducted. The study is non-interventional, which means that no medications or new forms of therapy are being tested.

All patients with osteosarcoma or a biologically related bone sarcoma who are currently being treated in Germany are eligible to participate in this study.