‘That’ Blood Test you may have read about

Sunday marked World cancer day, and the internet was filled with things to do with it! We had people showing off their unity bands, while others were sharing their uplifting stories of recovery. It was an important day, to raise awareness, to admire the fighters and to salute the survivors. While it is important to celebrate how far we have come, we must still remember those who have lost the fight. In solemn moments like those, the loss can seem overwhelming, but the pace at which new treatments are being developed is something very exciting!

I am sure we can all appreciate the importance of diagnosing and treating cancer in its early stages, as this greatly increases the chances of treatment being successful. In my endeavours to do ‘wider reading’ for medicine, I stumbled upon a headline about a ‘Blood test that can detect 8 different types of cancer’. In the moment, I didn’t get time to read it (as I was in the study area and was actually supposed to be studying), but I bookmarked it for later. When I got time (which as an A-level student, is rare) I went back to do more research, and this is what I found out:

How does the test work, and how was the research carried out?

The blood test, called CancerSEEK, works by searching for mutations (changes in the sequence of DNA) in 16 genes that commonly arise in cancer and in 8 proteins that are often released. The test recognises mutations in ctDNA (circulating tumour DNA) and protein biomarkers, which can be found in the blood. These biomarkers are ‘naturally occurring molecules, genes or characteristics by which a particular condition/disease etc. can be identified’. CancerSEEK was tested on 1005 patients with stage 1 to 3 cancers. The eight cancers it was tested on were: Ovary, liver, oesophagus, pancreas, stomach, colorectum, lung and breast. 812 healthy individuals (with no cancer) were used as a control population, to compare the results to. A patient’s result was classified as positive if the mutation in one of the 16 genes or the levels in one of the eight proteins was greatly elevated as compared to the healthy control population.

The Success of CancerSEEK

In summary, the median overall ability to find cancer was 70% for those 8 common cancers. Furthermore, sensitivity of the test to liver cancer in stage 1, was 100%, however, overall, the median sensitivity to stage 1 cancer was a low 43%.

CancerSEEK has been described as ‘promising’, although there is a lot more research to be done into it, mainly because one of the major limitations of the study was that all of the patients already had known cancers.

My thoughts on CancerSEEK

I think that this whole study is extremely exciting! If we can identify these 8 most common cancers, then the cases of cancer globally would be reduced immensely. This non-invasive test, in my opinion, once developed, will be much preferred over other, invasive means of diagnosing cancer, such as colonoscopy. On the other hand, CancerSEEK has a 1% false rate, which may cause concern for many people as they could be told that they have cancer, when in fact, they do not, so while CancerSEEK may help the situation, we may still require the invasive procedures to confirm whether a person has cancer or not. I absolutely agree with the main conclusions of most articles, that this test is promising, but requires a lot more development and research.

By Muskaan Jonathan

If you would like to find out more about CancerSEEK, here are the links to the articles I used:

https://www.medscape.com/viewarticle/891491#vp_5

http://www.telegraph.co.uk/news/2018/01/19/promising-blood-test-detects-eight-different-kinds-cancer-spread/

https://www.pancan.org/news/6-things-know-cancerseek-test-early-detection/

https://www.hopkinsmedicine.org/kimmel_cancer_center/cancerseek_faqs.html

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