CYFRA 21-1 test: what it shows and how the result is read

CYFRA 21-1 is a tumour marker — a protein fragment that comes from cytokeratin 19, a structural protein found in large amounts inside many epithelial cells. When such cells break down or multiply faster than usual, fragments of cytokeratin 19 get into the blood, and so the concentration of CYFRA 21-1 can rise. According to MedlinePlus, tumour marker tests in general are not intended to diagnose cancer in a healthy person — they are most often done when an oncological disease is already known. They help to assess the stage of the disease, to anticipate its likely course, to choose the treatment approach, to follow whether the treatment is working, and to watch whether the disease has come back after treatment. Like other similar markers, the amount of CYFRA 21-1 can rise not only in cancer. That is why the result of a single test is always assessed together with your doctor, the history of the illness, the clinical picture and other tests, rather than on its own and not as a diagnosis in its own right.

• When an oncological disease is already known — to obtain additional information about the stage and the course of the disease
• During cancer treatment (chemotherapy, surgery, radiotherapy) — following whether the body is responding to the treatment being given
• After treatment has been completed — checking periodically whether the disease has come back
• When a doctor wants to compare a new result with earlier tests, assessing how the value changes over time
• Together with other tests and imaging methods, when a broader picture of the oncological condition is needed