Tumour Markers

Tumour markers are substances found in the blood that indicate the presence of a malignancy. The best known tumour markers are for ovarian cancer.

CA125 is a marker that is produced by mesothelial cells from the peritoneum (inner skin of the abdomen), the pleura and the pericardium. It is expressed in 80% of all patients with ovarian cancer. Unfortunately it is not as accurate as clinicians wanted it to be: It is false negative in approx 33% of all patients with (early) stage 1 ovarian cancer. It is also false positive (elevated) in a very large number of benign, harmless conditions (endometriosis, benign tumours, etc). Therefore the differentiation between an ovarian cancer and other conditions based on CA125 is difficult.

CEA and CA19.9 are tumour markers indicating the presence of bowel cancer or mucinous type ovarian tumours.

HE4 is a novel tumour marker that has been marketed only recently. It has been introduced to Australia only in February 2011. It could complement CA125 and diagnose early stage ovarian cancers that are negative for CA125. For more read click here.

I use tumour markers to differentiate between benign and malignant tumours to the best of my abilities. Often tumour markers are used in combination with high-quality ultrasound to avoid unnecessary surgery, especially in medically impaired women. Currently, I do not use tumour markers for ovarian cancer screening because of a lack of evidence. CA125 also plays a role to select patients who require treatment for ovarian cancer.