Genome sequencing may help cancer detection

British researchers have developed a statistical model that uses genomic data to predict the risk of developing cancer of the oesophagus.

More work is needed before it can advance to clinical trials, but if successful it could streamline the process and make it less arduous for many people.

Oesophageal cancer, the eighth most common cancer worldwide, often develops from a condition called Barrett’s oesophagus. As such, people with this condition are closely monitored.

But only one in about 300 is actually diagnosed with cancer each year, the researchers say, and the monitoring procedures every two years can be intrusive, uncomfortable, stressful and time consuming.

Other recent cancer studies have shown that genomic mutations leading to cancer may occur many years before a patient is diagnosed with the disease, and that being able to identify these mutations could provide a new route to early diagnosis and treatment.

That’s what motivated the recent project led by Moritz Gerstung, from the European Molecular Biology Laboratory European Bioinformatics Institute (EMBL-EBI), and Rebecca C Fitzgerald, from the University of Cambridge.

Using genomic data from 88 patients with Barrett’s oesophagus, they looked for differences between patients who were ultimately diagnosed with cancer and those who were not. From this they developed a statistical model measuring each patient’s individual risk.

The data came from Addenbrooke’s Hospital in Cambridge, which has been monitoring patients for 15 years and was able to provide more than 800 samples, taken over time and from different areas of the oesophagus.

Writing in the journal Nature Medicine, the researchers say they were able to identify half of the patients later diagnosed with oesophageal cancer as “high risk” more than eight years before the diagnosis. This rose to 70% two years before diagnosis.

Just as importantly, the model also accurately predicted patients who were at a very low risk of developing cancer. Overall, the authors estimate that monitoring can be reduced for 50% of patients with Barrett’s oesophagus.

“The benefit of our method is twofold,” says co-author Sarah Killcoyne, from EMBL-EBI.

“The patients who have high-risk Barrett’s, which is likely to become cancerous, can receive treatment earlier, and individuals who have something that looks genetically stable, and unlikely to develop into the disease, do not need to undergo such intense surveillance.”