What is osteosarcoma?
Osteosarcoma is a rare form of bone cancer, making up under 1% of all cancers. Nevertheless, it is the most common primary bone cancer in children and young adults. It can also occur in older patients, generally aged 60 or older. While it can occur in many locations, it frequently begins adjacent to the knee, in either the femur or the tibia. It also commonly effects the shoulder, arising within the humerus.
What causes it?
These tumors occur more frequently during active growth periods, such as during a child’s adolescent years. Although many genetic mutations have been identified in these tumors, in most instances the main cause or driver of the disease remains unclear. There is no evidence that routine environmental, social, or dietary factors contribute to its development. However, prior radiation, chronic bone disorders such as Paget’s Disease, and certain rare inherited conditions such as Li-Fraumeni syndrome, Rothmund-Thompson syndrome and hereditary retinoblastoma, can increase an individual’s risk of developing osteosarcoma.
What are the symptoms?
Symptoms include a painful swollen firm area in or around a bone. This may be more obvious or visible in an arm or leg. If located within the pelvis or spine, it may be harder to visualize, and pain may be the main symptom. Patients may report varying degrees of discomfort even while sitting or at rest. They may experience pain that wakes them from sleep. Pain may prevent normal range of motion and patients may report stiffness, weakness, or other subjective senses of discomfort. Rarely, the bone may break in the absence of major trauma or other obvious cause.
How is it diagnosed?
Osteosarcoma is diagnosed using imaging studies, such as plain x-rays and MRI. A CT scan of the chest and either a PET scan or a bone scan is often obtained as well to detect the extent of the disease. Ultimately, a biopsy is required to sample the tumor and review its microscopic appearance.
How is osteosarcoma treated?
Osteosarcoma requires a comprehensive team approach, including the multi-disciplinary expertise of orthopaedic oncologists, pediatric oncologists, medical oncologists, radiation oncologists, musculoskeletal radiologists, bone and soft-tissue pathologists, nuclear medicine specialists, surgical oncologists, plastic and reconstructive surgeons among others.
Treatment includes both systemic chemotherapy and surgery, at a minimum. After a few months of treatment with chemotherapy, the tumor is surgically removed. Thereafter, additional chemotherapy is administered. Treatment generally spans 9-10 months.
In some select instances, other modalities, such as radiation is utilized as well.
Following the completion of treatment, patient will require close surveillance for a period of 5 years. This includes physical examinations and periodic imaging studies. Many patients continue to follow up even after 5 years, albeit at a reduced frequency.