Detecting ovarian cancer

Ovarian cancer is the sixth most common cancer among women in the UK, but because diagnosis is often made when the disease is more advanced, 5-year survival rates are only 46 per cent overall. The good news that this soars to a 90 per cent 5 year survival rate when tumours are detected early.

When it comes to detecting ovarian cancer, we do have a blood test which looks for the protein-based biomarker CA125. It is not particularly reliable and it only detects around half of early cancers.

Furthermore, it CA125 protein that is produced when a woman is suffering from a range of gynaecological conditions, and it is even often raised as part of a woman’s normal menstrual cycle. It is helpful as a first stage test so doctors may decide to refer a woman for an ultrasound and further tests, but it has lots of drawbacks, not least causing well women to suffer unnecessary anxiety.

Ideally, we should have a simple reliable test which is specific to ovarian cancer and picks up tumours at an early stage when the cancer is still eminently treatable. One way would be to develop a test which picks up DNA in the body produced by the ovarian cancer itself. The specific mutation on the DNA which leads to a deadly type of ovarian cancer, known as high-grade serous, has already been identified. I work with a group of scientists at the University of Cambridge who have been looking at ways to develop a DNA tumour test for some time now. We have already shown that the principle works in practice and have published results showing that we can detect tumour DNA in patients with recurrent ovarian cancer.

But detecting this DNA in women with very early stage disease is far more complicated.

To start with, there is only a tiny amount to be found and it is difficult to produce a test that is sensitive enough. All cells shed DNA in the circulatory system all the time and the amount being released by a small ovarian cancer tumour is very low. We are looking at ways to amplify the tumour DNA so that the test can pick up a mutation.

Ovarian cancer DNA is also confined to the abdomen and reproductive organs and doesn’t spread through the blood stream, so it might be better to use something like a cervical smear test, rather than a blood test. There is a direct connection between the fallopian tubes, through the womb, to the cervix, so cancer DNA could pass onto the cervix where it may be detected. This is our next line of research. It is very challenging but I am hopeful that it will just be a matter of time before we have a reliable test that can mean many more women are diagnosed with ovarian cancer when it is very treatable.