Tumour markers

This term refers to the measurement of tumour products that are secreted by the cancer. The ability to measure these products in the blood or urine or CSF (cerebrospinal fluid - the fluid that surrounds the brain and spinal cord) assists the doctor in the diagnosis of tumours (e.g. a raised urinary VMA is found only in phaeochromocytoma or neuroblastoma ) and when the level corresponds well to cancer cell number/tumour burden then the serial measurement of the marker can be very important in the assessment of the patient's response to therapy (e.g. the CA-125 levels in the blood in ovarian cancer and the HCG levels in the blood in testicular cancer).