Cancer blood test samples Credit: Flickr/CC BY-NC-ND 2.0
Ovarian cancer is the sixth most common cancer in women in the UK, with about 7,400 new cases every year. This number equates to approximately 20 diagnoses a day.
Early diagnosis is key to successfully treating cancer, and ovarian cancer is no exception. But as seen frequently with many different cancer types, there are a number of obstacles we need to tackle for early diagnosis to become a reality.
The answer for ovarian cancer could involve a blood test.
We often hear about blood tests when it comes to detecting cancer. And while many are still in the early phases of development, cancer blood tests do exist, and some are even currently being used in GP practices.
A team of researchers, based at the Universities of Cambridge, Manchester and Exeter and funded by Cancer Research UK and NIHR, have been investigating a blood test for ovarian cancer – CA125 – that’s already out there. Their research, published this week in PLOS Medicine, found it is far more predictive than we originally thought and could potentially pick up other forms of cancer.
The importance of early diagnosis
Like many other cancers, survival of ovarian cancer depends on the stage at which the cancer has been diagnosed.
Put simply – the earlier the better.
The differences in survival between an early stage and late stage diagnosis are significant. 93% of people diagnosed with ovarian cancer diagnosed at the earliest stage (stage 1) survive their disease for 5 years or more, compared to just 13% of those diagnosed at the latest stage (stage 4).
Sadly, ovarian cancer is often diagnosed late. The majority of women will be diagnosed when they notice symptoms, typically when they visit the GP. And while symptoms can occur at every stage of the disease, the symptoms are non-specific, such as abdominal pain and bloating, and can be hard to pinpoint.
Why investigate a test that we already have?
The CA125 test is a blood test used around the world, including in the UK, to help identify ovarian cancer in women who are already presenting with symptoms. Those who have above a certain level of CA125 in their blood are advised to follow on with further tests, such as an ultrasound.
How does the CA125 test work?
- CA125 is a protein often found on the surface of ovarian cancer cells and in some normal tissues. Women with ovarian cancer often have a high level of this protein in their blood.
- A high level of CA125 in your blood could be a sign of ovarian cancer. It can also be a result of other conditions such as endometriosis, fibroids and even pregnancy.
- If a test shows you have high levels of CA125, you may be referred for a scan to check for possible causes.
Back in 2011, the National Institute for Health and Care Excellence (NICE) recommended that women with symptoms of possible ovarian cancer be tested for CA125 in a primary care setting, typically at your GP surgery.
While the CA125 test has been studied in women in secondary care, for example, women with pelvic masses in a hospital setting, the test hadn’t been evaluated for women who had seen their GP with symptoms that could be ovarian cancer.
The research team, working as part of the CanTest collaborative, set to fill in this missing data.
“There’s around 7,000 women diagnosed with ovarian cancer in the UK each year. Picking up the disease early is really important because we’re more likely to be able to treat and cure the disease effectively if we do that…..”
“The CA125 blood test has been around and available to GPs for a while. But it’s never actually been evaluated in primary care,” explains Dr Garth Funston, from the University of Cambridge, who led the study.
“Tests perform differently depending on how you use them and who you use them in. So to really understand how this test performs, we needed to study it in the population in which it was used.”
Funston says that before this study, doctors relied on evidence and results from research conducted in other settings. “This study shows that it is a really useful test in helping to work out who to refer on for further investigation.”
The results are in
The study looked at 50,000 women who had seen their GP and took the CA125 test between 2011 and 2014.
This research found that 10% of women with higher levels of the protein biomarker were diagnosed with ovarian cancer, making an abnormal test 12 times more predictive than previous estimates had suggested.
What’s more, this study showed for the first time that an abnormal CA125 result in primary care was not only associated with ovarian cancer – over 350 women with high protein levels had the disease – it also found more than 380 women with an abnormal CA125 result had another type of cancer such as pancreatic, lung or bowel cancer. These results reflect how important it is that GPs remain alert to the risk of other cancer types when carrying out specific triage tests.
Age was a big factor that affected the results. The proportion of women with an abnormal test who had any cancer, was much higher in women aged 50 or over (33%) compared to women younger than 50 (6%).
“One of the most exciting things from this research is that we’ve been able to develop models which give the individualised risk or probability of a woman having cancer, based on their CA125 test level and their age,” Funston comments.
“We think this will be really useful in helping women and GPs make decisions about the need for further testing and referral,” he adds.
This research demonstrates a readily available and tangible test that can be used more often by GPs to give people more time with their loved ones.
Significant investment in diagnostic equipment and technology, along with NHS staff is urgently needed to diagnose more cancers at an earlier stage and save lives. Through the right investments and policies, the UK has the potential to become a world leader in the early detection and diagnosis of cancer.
– Dr Jodie Moffat, Cancer Research UK’s head of early diagnosis.
What does this mean for patients?
The team at Cambridge hope that this new, added insight on the performance of the CA125 test will help aid the diagnosis pathway for ovarian cancer.
Fiona Barve is a science teacher who lives near Cambridge. She was diagnosed with ovarian cancer in 2017 after visiting her doctor with stomach pains.
“I hadn’t heard of the CA125 blood test before my GP suggested that I take one. Although I was diagnosed at a late stage, the test helped identify the problem – I didn’t even know this test existed before. I’d like to see a day when tests like this are routinely used to help more people have their cancer diagnosed early,” she says. “I was fortunate my surgery, which I received within four weeks of being diagnosed and chemotherapy worked for me. Now I feel lucky to be around.”
Fiona has been cancer free since April 2019 and leads a fit and active life, working as a science teacher at her local school three days a week. She is monitored every 3 months by her consultant Professor James Brenton, a process which includes having regular CA125 tests.
Although the CA125 test is already being used in GP surgeries, this new data provides a great opportunity to encourage the use of the CA125 test as an effective triage tool.
“It would be fantastic to see the models we’ve developed integrated into the GP practice to help guide decisions about which patients need to be referred urgently for further investigation and which patients can be reassured. So I’d really like to see the models implemented and used,” Funston concludes.
Heidi March 31, 2021
Whilst the CA 125 should be routine, let us not forget that it isn’t the be and end all. In 2016 I was diagnosed with Paraneoplastic Syndrome and refer by a Rheumatologist to a Gynaecologist because of the link to ovarian cancer. At the time my CA 125 was only 16 where I was told there was nothing to worry about. However, in 2020, I had surgery for advance low grade serous ovarian cancer – my CA 125 was only ever 20! All the warning signs were there for the medically trained but no one thought about looking at me as a whole. Looking back at my medical history from both NHS and Privately, if the links were made then not only my situation would be infinitely better but the cost to the NHS would be less.
Jo January 29, 2021
Reassuring to read. I has abdominal pain twice last week and my dr referred me for a CAT125 blood test yesterday. Results today said its at 69, which is higher than it should be. Now been referred for a scan next week. Fingers crossed whatever it is is treatable! I survived breast cancer in 2008.
Sandra Forsythe November 18, 2020
Fantastic news you do an amazing job
Sandra Koniotes November 9, 2020
This test should be carried out as a routine on all women presenting with symptoms of bloating, sickness, constipation. Luckily for me my gp tested me immediately the result of which was a ca125 of 3501. I was diagnosed stage 3c high grade serous in May 2019. After extensive surgery including bowel resection and chemotherapy , i am now 11 months no evidence detected! Im so grateful to my doctor for sending me for testing immediately! Symptoms can be so non specific,
Mary waterman November 7, 2020
This test may be the easiest way to get too the bottom of my troubles. Without my mum now i can’t get the tests i need. My only option was her sister and she wont. (I respect her reasons). However i dont have the money for the genetics test.
Im so proud of all the research and the continued support.
Thank you all ❤️
Melissa Kam November 7, 2020
My ovarion cancer was detected through ca125. I had scan and surgery done immediately when I was living in Malaysia and now I’m cancer free for 20 years.
Jules November 7, 2020
Hi I’m Jules I lost my mum who was only 69 years old to a bravely fought 4 year battle to initially ovarian cancer. I’m an Intensive Care Nurse and people forget to talk to me like I’m her daughter too. However I spent so many special moments with my mum that I will never forget. She tried everything they offered her she tried all the research she could. I wouldn’t be who I am today without mymum xx
Beverly Curzon November 7, 2020
I had a total hysterectomy in1984 for ovarian cancer followed by radiotherapy. I am now 81
so I feel I have been very lucky and grateful to the treatment and follow up that I received.
Barbara November 7, 2020
I read an article about the CA125 blood test back in 2011 and believe it’s every woman’s right to be tested for Ovarian Cancer on a regular basis, just like mammograms. My lovely mum passed away with this cruel disease and I wanted to be re-assured this wasn’t going to happen to me, so I started requested regular CA125 blood tests from the year 2011 right up to January 2020 and thank goodness all my blood tests came back clear.
I passionately feel there should be more publicity on the CA125 blood test, so every single woman can be tested. Thanks for all your brilliant work you do for Cancer Research, it’s so much appreciated, thank you.
Trish Derbyshire November 6, 2020
Had radical surgery in 2017 due to stage4 ovarian c – feel absolutely great now despite having a bag – which I call my bag for life. My Surgeons etc were absolutely fantastic and I am indebted to them.
Dawn Hill November 6, 2020
All women should have this test just as we have our smear test especially those over 50
Susie Greenwood November 6, 2020
This is good news …so can we now ask our Gp to take a blood rest as routine check up?
Lilly Matson November 10, 2020
Thank you for your question.
If you have symptoms that could be ovarian cancer, such as persistent bloating (also called distension), feelings of fullness/loss of appetite or pelvic/abdominal pain, you may choose to proactively raise the possibility of having a CA125 blood test with your GP, particularly if you are over the age of 50 (as the test seems to be more helpful in this group). On the basis of current evidence and guidance, we would not expect the GP to offer a CA125 test to someone who does not have any symptoms.
Lilly, Cancer Research UK
Carole Farquhar November 6, 2020
Really eye opening and very informative and reassuring. Keep up the great work in keeping us all informed.
Lorraine Ashton November 6, 2020
At 45 years old I was told that I had endometrial cancer and ovarian cancer however I have never had a high CA125 level once. I hope go do not diagnose ovarian cancer just by ca125 levels alone but every woman should have a scan urgently as well.
Pat Murray November 5, 2020
I took part in this trial & went to Llandudno once a year to give blood – the very last year an abnormality was detected turned out to be an ovarian cyst!! I was so impressed.
Judith November 5, 2020
This is such an easy, non-invasive test that I hope that it will one day be made a routine test for all women especially those over 50. I was diagnosed with ovarian cancer in 1996. Surgery and chemo have meant I am still alive 24 years later. 5 years ago I was diagnosed with breast cancer following a routine mammogram. I have just received the all-clear proving that screening and early detection is vital in surviving cancer.
Betty Higson November 5, 2020
I was diagnosed with stage 4 11years ago I can’t praise the doctors and Macmillan enough.
PETER THOMPSON November 5, 2020
A really good article, and a lot of good information in the comments section too. I will mention this blood test to my GP ( mainly for my wife and daughters ). Thank you everybody.
Philip Hemingway November 5, 2020
I am surprised to recently read about CA125 markers being found to indicate Ovarian cancer. Unfortunately I lost my wife to this disease over 16 years ago. She was diagnosed with ovarian cancer 24 years ago, and went into remission for nearly 5 years following surgery/treatment. Her consultant used her CA125 marker levels to check on her health, and every time Jane’s marker levels went up, the cancer was active.
I am a little surprised it has taken all this time to come to this conclusion. It seemed to me many years ago that there was a link.
I am not suggesting anything other than this should have been researched some years ago.
Julie November 4, 2020
Be aware that increased CA125 can be due to other things – I had liver failure which caused a raised CA125 level but wasn’t in any way cancer related I had other signs of ovarian cancer – ascites plus a mother who had had ovarian cancer at a young age – the ovarian cancer diagnosis delayed the true cause of my illness being treated quickly
Kamaljit November 4, 2020
This is so good mine was raised can 125 it was 286 told by my gp I had ovarian cancer had M R I scan showed no masses on my ovaries I do have a mass in my uterus which is 8cm big told by a doctor I have uterine cancer M r I scan showed it looked more like a large fibroid than later diagnosed with breast cancer stagex1 which was a early cancer thanks you for your good work
Robyn Free October 30, 2020
Definitely – it is also an useful indicator as to whether treatment – especially chemo is working or not. My CA125 was 4000+ on diagnosis, down to. 357 after radical surgery and down to normal range 23 (should be below 35) after 3 rounds of chemo.
Michele October 29, 2020
Do it… it would have definitely been detected in my blood as my number was 4,172
Carole Hultum October 29, 2020
Excellent article. CA125 has been used for many years as a monoclonal antibody in Immunocytochemical staining methods to diagnose ovarian cancer metastases in Histopathology. Great breakthrough.
Hilary Bates October 29, 2020
Awareness among GPs also needs to be raised. CA125 is an inexpensive test, and ultrasound is a relatively inexpensive scan. If GPs thought about ovarian cancer earlier in the diagnostic process it would help. Blood test for all women over 50 presenting with symptoms like IBS, and for younger women with persistent symptoms. I participate in a programme called Survivors Teaching Students, which aims to educate the GPs (and other doctors) of tomorrow. I never saw my GP, because I collapsed in excruciating pain and was admitted as an emergency. All the relevant tests were done in hospital. I was 48, had stage Ic disease and am still cancer free 14 years later.