A simple blood-based test for early detection of colorectal cancer

*Please note that this test is only available when booked as part of our Check-Ups and not as a standalone test.

We are very excited to announce the launch of the Septina-9 blood test which is a revolutionary new epigenetic blood test to assess the risk of bowel cancer. Advances in gene technology can now be used to identify the possibility of having colorectal cancer, by taking a simple blood test.

The test detects the epigenetic biomarker Septina-9 in blood plasma. This biomarker – methylated DNA of the Septina9 gene – correlates strongly with the presence of colorectal cancer. This test is the second generation test with greater sensitivity and specificity for the detection of colorectal cancer.

What is the new Septina-9 test?

The Septina-9 test is a new blood test that can be performed as a first step in the early detection of colorectal cancer by detecting a marker in blood plasma that is specific to colorectal cancer. A sample of blood will be taken at Preventicum and sent to a diagnostic laboratory for detailed analysis. If the marker is detected in the sample, there is an increased likelihood of having colorectal cancer. In this case the person should undergo a colonoscopy to confirm the diagnosis.

How does the test work?

Even at the earliest stages, colorectal tumours shed genetic material or DNA into the bloodstream. The Septina-9 test is able to detect that tumour marker in a blood sample. A positive test result indicates that there is an increased likelihood of the presence of colorectal cancer. This has been established in multiple independent clinical studies.

What are the advantages of the Septina-9 test over MRI colonography?

The Septina-9 test is a blood test that can be carried out alongside the extensive blood analysis that already forms part of all our Check-Ups. Since opening our doors in 2005, we have offered MRI colonography as part of our Ultimate Plus Check-Ups; however from Summer 2017, we are offering the Septina-9 blood test for early detection of colorectal cancer. We have been looking for a more convenient reliable alternative to MRI colonography which doesn’t involve two days of bowel preparation including laxatives. The second generation Septina-9 test, being a blood test is much more convenient and has both good positive and negative predictive values in clinical trials in persons of average risk in the general population. We believe that some clients will prefer this new method which can be used as a good “rule out” test in those of average risk in the population.

Does the test replace a regular colonoscopy?

No. It is our current belief that the blood test should provide a convenient and high-quality alternative to other non-invasive screening tests (e.g. faecal occult blood test/ FOBT) for the first step in colorectal cancer early detection. Optical colonoscopy is still regarded as the gold standard screening test for early detection of bowel cancer and a negative colonoscopy would normally mean a low risk of developing bowel cancer for at least the next 5 years.

Can I have a colonoscopy instead?

We can still arrange an optical colonoscopy on a different day in a London centre of excellence as an alternative if preferred or if the person is in a higher risk category for bowel cancer risk (e.g. strong family history of early bowel cancer, worrying symptoms, history of bowel cancer previously etc.) Optical colonoscopy is still considered the gold standard bowel cancer test in expert hands and we can arrange this if indicated /preferred. We only send our clients to very experienced specialists whom we know and trust.

Who should take the Septina-9 test?

The test is suitable for everyone with an average risk of colorectal cancer, who has no symptoms, but wants to take part in colorectal cancer screening. The purpose of the test is not to replace screening colonoscopy. Instead, it is aimed at people looking for a safe alternative. We suggest that the Septina-9 test is offered to clients aged 50 and over. It may also be added on the day of the Check-Up.

Do I have to prepare before taking the test?

Unlike some other methods of bowel cancer screening including the MRI colonography, conventional colonoscopy and some stool-based methods for colorectal cancer early detection, there are no dietary restrictions or laxative required prior to the test. The blood sample can be taken at any time but it will be done at the same time as our routine extensive blood analysis.

How long do I have to wait for the results?

Currently the turnaround time for the test is around 17 working days in view of the highly complicated, precision technological processing required.

What does a negative test result mean?

This means that it is very likely with a high degree of certainty (99%) that you currently do not have colorectal cancer. The test would normally be repeated in 1-2 years.

If I tested negative, can I be confident that I definitely do not have
colorectal cancer?

No screening test can ever fully exclude the presence of colorectal cancer, not even the gold standard colonoscopy (which has an estimated sensitivity of about 97%) and the same applies to the Septina-9 test. There is a very small risk of a “false negative” result. However one of the strengths of this test is its very high negative predictive value. In other words a negative result means a very high probability that you really do not have colorectal cancer.

How often should I have the blood test?

Colorectal cancer arises spontaneously and probably develops over a period of about 10 years so it is still advisable to participate regularly in a screening program if the test is negative. The manufacturers of the Septina-9 test advise having the test every 1-2 years.

If I tested positive for Septina-9, does that mean I have colorectal
cancer?

Not necessarily. It means that you should have a follow up test called a colonoscopy.A positive Septina-9 result means that you have an increased risk of having colorectal cancer, although as with many other diagnostic tests, a false positive result can occur. That is why your Preventicum doctor will recommend that you receive a follow-up optical colonoscopy for a definitive diagnosis. The Septina-9 test in studies has a high positive predictive value which means that a positive result gives about a 45% chance (one in two) of being positive due to the presence of colorectal cancer (a true positive).

On average one person in every two with a positive result will be found to have colorectal cancer which is much more accurate than other non colonoscopy tests.

Can I take the Septina-9 blood test as a stand-alone test?

At the moment, the Septina-9 test is only available as part of our Preventicum Check-Ups.  It can be added to our Ultimate and Essential Check-Ups.

What is the cost of the Septina-9 test?

The Septina-9 blood test costs £250 when added to one of our Preventicum Check-Ups.

Where else can I take this test?

Preventicum is one of the very first centres in the UK to offer this additional test as part of our Check-Ups. Currently it is available in some European countries. Like all advances in medicine we suspect that it will become increasingly available in the future.

Does this test pick up pre-cancerous polyps?

Some research has shown that it may pick up some polyps but it is designed to pick up genetic markers found in colorectal cells. It therefore cannot be relied upon to pick up pre cancerous polyps.

What are the specificity, sensitivity, negative predictive value and
positive predictive value of the Septina-9 test?

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What does ‘specificity’ mean?

The statistical probability that an individual who does not have colorectal cancer will be correctly identified as a negative, expressed as the proportion of true negative results to the total of true negative and false positive results.

What does ‘sensitivity’ mean?

The proportion of individuals in a population that will be correctly identified when administered a test designed to detect a particular disease (in this case the Septina-9 test for risk of colorectal cancer), calculated as the number of true positive results divided by the number of true positive and false negative results.

What does ‘negative predictive value’ mean?

If the Septina-9 test is negative, its negative predictive value is about 99%. No screening test can ever fully exclude the presence of colorectal cancer, not even the gold standard colonoscopy (which has an estimated sensitivity of about 97%) and the same applies to the Septina-9 test. There is a very small risk of a “false negative” result. However one of the strengths of this test is its very high negative predictive value. In other words a negative result means a very high probability that you really do not have colorectal cancer.

What does ‘positive predictive value’ mean?

The probability that a positive result is truly positive and that the disease is really present.  The Septina-9 test in studies has a high positive predictive value which means that a positive result gives about a 45% chance (one in two) of being truly positive due to the presence of colorectal cancer (a true positive).On average one person in every two with a positive result will be found to have colorectal cancer which is much more accurate than other non colonoscopy tests.