Osteosarcoma is a common type of bone cancer that mostly affects children and teenagers. It often starts at the ends of long bones where bone grows quickly. Symptoms include pain and swelling in the affected area. The exact cause is unknown but may involve genetic and environmental factors. Diagnosis usually involves imaging tests and a biopsy to confirm cancer cells. Treatment typically includes a combination of surgery to remove the tumor and chemotherapy to kill cancer cells. Radiation therapy may also be used in some cases. Early detection and treatment improve the chances of survival. Regular follow-up is important to monitor for recurrence.