London, July 21 (IANS): A pill on a string can help doctors detect esophageal cancer at an early stage, says a new study.

Understanding how esophageal cancer -- cancer of the gullet -- develops and the genetic mutations involved could help doctors catch the disease early, offering better treatment options for the patient.

"The trouble with Barrett's esophagus is that it looks bland and might span over 10 cm," explained Rebecca Fitzgerald from the University of Cambridge.

A sample was more likely to pick up key mutations if taken using the Cytosponge, developed by Fitzgerald.

The Cytosponge when popped up as a pill dissolves to reveal a sponge that scrapes off cells.

Once withdrawn up the gullet, the Cytosponge allows doctors to collect cells from all along the gullet.

The standard biopsies, on the other hand, take individual point samples.

"We created a map of mutations in a patient with the condition and found that within this stretch, there is a great deal of variation amongst cells. If you're taking a biopsy, this relies on your hitting the right spot. Using the Cytosponge appears to remove some of this game of chance," Fitzgerald noted in in the journal Nature Genetics.

The researchers found patterns of mutations in the genome -- where one 'letter' of DNA might change to another, for example from a C to a T -- that provided a 'fingerprint' of the causes of the cancer.

"Barrett's esophagus and the cancer share many mutations, but we are now a step closer to understanding which are the important mutations that tip the condition over into a potentially deadly form of cancer," said co-author Caryn Ross-Innes from Cambridge University.

Barrett's esophagus is most often diagnosed in people who have long-term gastroesophageal reflux disease (GERD) - a chronic regurgitation of acid from the stomach into the lower esophagus.

Barrett's esophagus is associated with an increased risk of developing esophageal cancer.