Tumour markers are substances found in the blood that indicate the possible presence of a malignancy. The best known and researched tumour markers are available 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 large number of benign gynaecological (endometriosis, benign tumours, fibroids, adenomyosis, etc) and non-gynaecological (arthritis, pleuritis) conditions. Therefore the differentiation between an ovarian cancer and other conditions based on CA125 is difficult.
Recently we published our results on CA125 in uterine cancer. If CA125 was elevated, there was a significantly increased possibility that tumour spread outside the uterus is found at surgery.
CEA and CA19.9 are tumour markers indicating the presence of bowel or pancreatic cancer or mucinous subtypes of ovarian tumours.
HE4 is a novel tumour marker that has been introduced in Australia only recently. It could complement CA125 and diagnose early stage ovarian cancers that are negative for CA125. The greatest use of HE4 is to exclude ovarian cancer in elderly and multi-morbid women who we can spare surgical exploration. More recently we researched the issue of HE4 in uterine cancer and found that HE4 predicted better than any other marker the presence of aggressive disease within endometrial cancer. For more detailed information on HE4 click here.
Beta HCG is a most accurate tumour marker for Gestational Trophoblast Disease.
I use tumour markers to differentiate between benign and malignant ovarian tumours. Often tumour markers are used in combination with high-quality medical imaging (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.