WHAT IS CHORDOMA?
Chordoma is a rare form of bone cancer. It most commonly occurs in the spine or the skull. Chordoma is treatable. Unfortunately, though, following treatment it can come back (usually in the same place) – this is called a relapse or local recurrence. In some cases, it can also metastasise (spread) to other parts of the body.
The base of the skull and the bones of the neck (known as the cervical spine) are the most common locations of chordoma in children. More rarely, it can occur in the bones at the bottom of the spine (in what is known as the sacrum and coccyx regions, or the tail bone).
Most chordoma patients are in their 50s and 60s. Chordoma in children (called paediatric chordoma) is very rare, making up only about 5% of all cases.
Chordoma affects 1 in 20 million children every year – that’s around 350 children worldwide, and around 3 children in the UK. Although the rarity of chordoma in children may seem incredibly isolating, the fact that you have found this site means you are no longer alone.
Chordoma is grouped into four types, depending on what the cancerous cells look like under a microscope. Two of these types are more often found in children – poorly differentiated (also known as INI-1 negative chordoma) and the dedifferentiated form. You may have heard one of these terms in reference to your child’s diagnosis:
- Conventional (or classic) chordoma is the most common form of chordoma – accounting for around 80-90% of all adult and child cases.
- Dedifferentiated chordoma can be faster growing, more difficult to treat and more likely to metastasise than conventional chordoma. This type of chordoma is rare, occurring in only about 5% of all patients.
- Chondroid chordoma makes up between 5-15% of all adult and child chordoma cases and most frequently arises in the base of the skull. This type of chordoma has some similarities to a more common form of bone cancer, known as chondrosarcoma. The distinction is made between the two cancers by the presence of a protein called brachyury, which is found in all chordomas other than the dedifferentiated subtype but is absent from chondrosarcomas.
- Poorly differentiated chordoma is a more recently recognised form of chordoma and is characterised in most cases by the loss of the expression of a protein called INI-1 (hence its other name ‘INI-1 negative chordoma’). This type of chordoma is rare, accounting for less that 2% of all chordomas but is more common in children and young people, accounting for up to 7% of chordomas in the under 30 age group. It occurs most commonly in the base of the skull and in the bones of the neck. Even more rarely, loss of INI-1 is also seen in the conventional and dedifferentiated forms of chordoma. Poorly differentiated chordoma is faster growing, more likely to metastasise and therefore more difficult to treat than chordomas without loss of the INI-1 protein.
What causes chordoma?
We don’t know the answer to this question, but researchers are working hard to try and find out.
Chordoma begins in cells of a tissue called the notochord. The notochord is essential for the development of a baby’s spine in the womb. The notochord tissue is eventually replaced by bone but it is thought that some notochord cells remain in the bones of the spine and skull – and it is these cells that can become cancerous and develop into chordoma.
What causes notochord cells to become cancerous is not known but is an area of ongoing research.
In exceptionally rare cases, chordoma is a familial disease and can be inherited but there are only a handful of families in whom this has been reported.