osteosarcoma
Meaning of osteosarcoma: The tumor makes bone, which is what gives it away on an X-ray and what separates it from cancer that merely arrived in bone.
Definition of osteosarcoma
Osteosarcoma is a cancer arising from the cells that build bone, so the tumor lays down disorganized bone of its own as it grows. It develops most often near the ends of the long bones around the knee and shoulder, and most often during the growth spurt of adolescence. It is the most common cancer that starts in bone rather than spreading there.
How osteosarcoma is built
- oste/o Combining form · Greek bone
- sarc/o Combining form · Greek flesh, connective tissue
- -oma Suffix · Greek tumour, mass, swelling
A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.
Who develops it, and where?
Age falls into two peaks. The larger comes in the teenage years and early twenties, and the tumors cluster at the sites growing fastest: the lower end of the thigh bone, the upper end of the tibia, and the upper arm bone near the shoulder. Height and rapid growth are part of the pattern, which is also why large dog breeds develop the same tumor. A second, smaller peak arrives in later life, and there the tumor usually rises in bone that was already abnormal, whether from Paget disease or from a region treated with radiation long before.
| Setting | What lies behind it |
|---|---|
| Adolescence and early adulthood | Arises in normal bone during rapid growth, close to the growth plates |
| Later life | Arises in bone altered by Paget disease or by earlier radiation treatment |
| Inherited predisposition | Families carrying an altered retinoblastoma or TP53 gene face a raised risk |
What does it look like on imaging?
Distinctive enough that a plain X-ray often raises the suspicion first. Because the tumor both destroys existing bone and manufactures new bone badly, the image shows a mottled mixture of holes and dense patches rather than one or the other. As the growth lifts the fibrous sheath covering the bone, that sheath lays down reactive bone at its edge, giving a triangular spur, and fine spicules radiate outward from the surface in a pattern likened to a sunburst. A soft tissue mass usually extends beyond the bone itself. None of this replaces a tissue sample, and the sample is planned carefully, because the track the needle takes has to be removable with the tumor at the eventual operation.
How is it treated?
With drug treatment and surgery in combination, in a set order. Chemotherapy comes first, shrinking the tumor and attacking deposits too small to see, then the tumor is removed with a margin of healthy tissue, and drug treatment resumes afterward. Most operations now save the limb, replacing the removed segment with a metal implant or bone graft, though amputation is still necessary for some. How much of the tumor was killed by the first round of drugs is assessed in the removed specimen and carries information about outcome. The lungs are where it spreads first and most often, so imaging of the chest is part of the initial assessment, and lung deposits are sometimes removed surgically. This combined approach, rather than any single drug, is what changed survival from the era of surgery alone, and it is why treatment is concentrated in centers that handle bone cancer regularly.
Also known as
Used in a sentence
Imaging of the distal femur revealed a lesion suspicious for osteosarcoma.
Good to know
Osteosarcoma, a cancer that originates in bone tissue itself, is distinguished from cancer that has metastasized to bone from a tumor elsewhere, since the two are managed very differently.
Word origin
Where “osteosarcoma” comes from
Formed from osteo-, Greek for bone, and sarcoma, itself from sarx, meaning flesh, and -oma, meaning tumor.