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Are blood tests the holy grail for early diagnosis of ovarian cancer?

30 November 2020


Our Research Grants & Impact Manager, Faye, takes a look at the upcoming trial and what it could mean for women with ovarian cancer.

What is the Galleri test?

Last week the government announced that the NHS will be trialing a new potentially groundbreaking blood test that claims to detect more than 50 types of cancer in their early stages. The Galleri blood test, developed by a California based company called GRAIL, will be piloted with 165,000 disease free and symptomless patients aged between 50-79. An additional 25,000 people with possible cancer symptoms will also be included on the trial through GP hospital referrals. The test detects abnormal DNA from cells in the bloodstream. Results from the trial are expected in 2023, and if successful could be rolled out to more participants. 

The government hopes the test will help towards the NHS Long Term Plan to diagnose three quarters of cancers early (at stage one or two) by 2028. Diagnosing cancers earlier means patients can access treatments sooner and have higher chances of survival. When a woman is diagnosed with ovarian cancer at stage 1, she has more than a 90% chance of surviving five years beyond her diagnosis. Unfortunately, only 30% of women with ovarian cancer are diagnosed at this early stage. This is potentially exciting news for patients with cancers that are difficult to diagnose early, such as ovarian cancer. The scientific community think the results so far have been promising, however believe the trial will need to answer several important questions before we will know if the test really works in detecting ovarian cancer at an early stage.

What have studies shown about the effectiveness of the test so far?

Galleri so far has shown it can pinpoint the locations of cancers very well and pick up a large number of cancer types, which could highlight people that need further investigation. However, the test will need to show that it does not pick up excess false positive results in the population, which could cause great anxiety. In earlier experiments the test showed only a 20% sensitivity for picking up stage 1 cancers. This means that in 100 people with early stage cancer, the test picked up 20 of those as having disease. This is because it is difficult to detect small amounts of DNA in blood. The NHS trial will need to show higher sensitivity for Galleri to be an effective early detection tool for cancer.

Galleri has only been tested in 37 women with ovarian cancer, meaning we cannot for certain know how well the test can help this group of patients yet. Hopefully the trial will give more answers to this and other questions. 

Ovarian Cancer Action CEO Cary Wakefield says; “It is exciting to see the Government and NHS prioritising early detection which is crucial towards improving ovarian cancer survival rates and we look forward to seeing the results of the trial. Large clinical trials like this are important to develop new early detection tools and the data collected could be used by other scientists to make important discoveries. However, we still need to be looking at all possible avenues for early detection in order for more women with ovarian cancer to access curative treatment”.

What is OCA doing to improve early detection for women with ovarian cancer?

Professor Ahmed Ahmed from the University of Oxford OCA funded project is looking to better understand how ovarian cancer starts, so it can be detected and treated before the cancer even develops. Being able to screen women for precancerous lesions could mean significantly less women being diagnosed with late stage disease, which could drastically improve survival rates. We are also investing in research looking at the possibility of developing a nationalised and personalised cancer screening and prevention programme. Ovarian Cancer Action funded researcher, Dr Jon Krell (Imperial College London) wants to see if an ovarian and breast risk cancer assessment tool he has designed can guide women in making informed decisions about undertaking personalised disease prevention measures. Findings from the project will improve our understanding of how best to implement genetic and non-genetic risk assessment in women who carry genetic faults in BRCA1/2 genes in the general population. In a recent report, the Government highlighted the need for risk assessment tools like this to successfully screen for cancer in the future. 

To read more about Professor Ahmed and Professor Krell's work click here.