Gaining a definitive diagnosis
Following a physical examination and blood tests to rule out other possible diagnoses, it is very common to be referred to a bone cancer specialist for a second opinion and confirmation of the diagnosis (see more about specialist centres in the Treatment section).
Imaging tests such as CT (computerised tomography), PET (positron emission tomography) and/or MRI (magnetic resonance imaging) scans can provide useful information on the exact location of the chordoma but cannot definitively diagnose it.
A biopsy is needed to definitively confirm the diagnosis of chordoma. A biopsy is a specialist procedure that takes a small sample of the affected bone, so it can be examined under a microscope by a type of doctor called a pathologist. A needle biopsy is done most frequently, which requires the insertion of a very fine needle into the affected bone tissue to draw out a small sample for examination.
One of the proteins the pathologist will be looking for is brachyury, which helps them distinguish chordoma from other types of cancers. The test undertaken to detect brachyury is known as immunohistochemistry (performed in the pathology lab).
Immunohistochemistry is also used to test for INI-1 loss, which helps to determine the subtype of chordoma (see the What is chordoma section for more information on the INI-1 protein). Testing for INI-1 is very important in children because INI-1 negative chordoma is more common in children, and different treatment options may be recommended for this type of chordoma.
Results from a biopsy can take up to two weeks to analyse but they should enable doctors to confirm the presence and specific type of chordoma.
This page features content originally published by The Chordoma Foundation and is reproduced with permission.