Gene scanning 'could improve screening for oesophageal cancer'

“Simple test can now reveal which heartburn patients are at risk of oesophageal cancer,” is the hopeful headline in the Daily Mail, reporting on a new study from researchers at Queen Mary University of London.

The researchers have been investigating whether a test for patients with Barrett’s oesophagus may be able to predict the likelihood of the condition progressing to oesophageal cancer.

Barrett’s is linked to gastro-oesophageal reflux disease (GORD), where acid leaks from the stomach back up into the throat. Stomach acid can aggravate the cells, so there is the potential for this condition to turn cancerous.

It’s hard to precisely estimate cancer risk with this condition, however. The current thinking is around 1 in 10 people with GORD will develop Barrett’s. Out of these people, around 1 in every 10 to 20 people will go on to develop oesophageal cancer.

So while the overall risk is small, it can still be distressing because of the uncertainty of outcome for people with Barrett’s.

This latest research involved taking oesophageal cell samples from a sample of patients with Barrett’s about three years apart to look at what factors predicted progression.

The researchers found progression was mostly linked to the degree of genetic diversity in the cells. Or, in the words of the lead researchers, some cells were just “born to be bad”.

The follow-up time in this study is short, and it’s not clear whether other risk factors were accounted for in the analysis or whether there are steps people can take to reduce their risk of cancer.

No doubt further larger studies of this technique are now being planned. 

Where did the story come from?

The study was carried out by researchers from a number of institutions, including Queen Mary University of London and the University of Amsterdam.

Funding was supported by the Dutch Cancer Foundation, the Netherlands Organization for Scientific Research, Fonds NutsOhra, the European Research Council, the Gut Club Foundation, and Abbott Molecular.

It was published in the peer-reviewed Nature Communications on an open access basis, so it is free to read online.

The Mail’s reporting was accurate, providing information on oesophageal cancer, risk factors for the disease, and a description of Barrett’s oesophagus. 

What kind of research was this?

This prospective cohort study aimed to assess whether a test performed on patients with non-cancerous Barrett’s oesophagus may be able to predict whether the condition will progress to oesophageal cancer. 

Barrett’s oesophagus is a condition where damage from the stomach acid eventually causes the cells in the lining of the oesophagus to change abnormally. It is often caused by acid reflux.

The abnormal cells are at an increased risk of becoming cancerous in the future, although this risk remains small. It’s estimated 1 in every 10 to 20 people with Barrett’s oesophagus will develop cancer within 10 to 20 years.

This type of study is useful for investigating links with factors that may be associated with cancerous change.

What did the research involve?

The researchers recruited adult patients with Barrett’s oesophagus from an academic medical centre and six hospitals in The Netherlands.

Participants had to be aged 18 years or over and have endoscopy evidence of Barrett’s oesophagus and no features of active oesophageal cancer.

All patients that developed cancerous change or oesophageal cancer within six months from the initial endoscopy were excluded from the study.

Endoscopic examinations with cell biopsy were carried out at the start of the study and then about every two to three years.

The researchers carried out laboratory tests on the biopsy samples to identify potential genetic markers and other disease features associated with progression. 

What were the basic results?

A total of 320 people with Barrett’s oesophagus were included in the study, and were followed for an average period of 43 months.

During this time 20 (6.3%) people progressed, while eight people developed high-grade cancerous change and 12 developed oesophageal cancer.

The researchers found participants with little genetic diversity in their cell samples were unlikely to progress to cancer.

However, the opposite is true when genetic diversity is present. The researchers claim some cells are “born to be bad”.

How did the researchers interpret the results?

The researchers concluded that genetic diversity correlates with the risk of Barrett’s oesophagus progressing to cancer.

They say the level of genetic diversity over time does not appear to have an effect on the risk of progression to cancer – it seems to be  predetermined by the baseline level of diversity.

Conclusion

This prospective cohort study aimed to see whether a test performed on patients with non-cancerous Barrett’s oesophagus may be able to predict whether the condition progressed to oesophageal cancer. 

Overall, they found genetic diversity in the oesophageal cell samples at the start of the study seemed to be linked to the risk of cancer progression.

However, the research has limitations to consider:

• By design, this study is only able to draw links – it does not propose treatment or lifestyle steps to be taken to reduce risk.
• The sample of patients in this study is small, so we cannot rule out that any associations seen are down to chance.
• The length of follow-up it not sufficiently long to see how many of the participants went on to develop cancer, as this can take 10 to 20 years.
• It is unclear whether the researchers have taken into account other risk factors for oesophageal cancer, such as smoking, drinking too much alcohol over a long period of time, being overweight or obese, and having an unhealthy diet.

The future aim of such a test could be to reduce the need for regular monitoring in patients at low risk of going on to develop cancer. But more research is needed to confirm the use of such a test.

The exact cause of oesophageal cancer is unknown, but stopping smoking, cutting down on alcohol, losing weight and having a healthy diet may all help reduce your risk.

Links To The Headlines

Simple test can now reveal which heartburn patients are at risk of oesophageal cancer. Mail Online, August 19 2016

Links To Science

Martinez P, Timmer MR, Lau CT, et al. Dynamic clonal equilibrium and predetermined cancer risk in Barrett’s oesophagus. Nature Communications. Published online August 19 2016