Camera pill could diagnose cancer
A SWALLOWABLE camera-in-a-capsule could help doctors spot early signs of oesophageal cancer, research has shown
The transparent device, about the size of a large multivitamin pill, contains a rapidly rotating laser that shines a beam of near-infrared light onto the wall of the oesophagus, or gullet, the pipe that carries food to the stomach.
Sensors record the light reflections and produce detailed microscopic images that can reveal cell changes associated with Barrett’s oesophagus, a pre-cancerous condition linked to heartburn and acid reflux.
A string-like tether allows the device to be pulled back up and transmits images to a monitor.
In tests on 13 unsedated volunteers, including six with Barrett’s oesophagus, the capsule was able to image the whole gullet in less than a minute.
A full procedure involving four passes down and up the oesophagus took just six minutes.
Current screening for Barrett’s oesophagus takes well over an hour and involves passing an endoscope – a flexible telescope – down a patient’s throat.
The new device revealed subsurface structures not seen with traditional endoscopy and clearly identified signs of Barrett’s oesophagus, the US scientists reported yesterday in the online edition of Nature Medicine journal.
Professor Gary Tearney, from Massachusetts General Hospital, said: “The system gives us a convenient way to screen for Barrett’s that doesn’t require patient sedation, a specialised setting and equipment, or a physician who has been trained in endoscopy.
“By showing the three-dimensional, microscopic structure of the oesophageal lining, it reveals much more detail than can be seen with even high-resolution endoscopy.”
Prof Tearney said there were initial concerns that data might be missed because of the small size of the capsule. However, these fears proved unfounded.
“We were surprised to find that, once the pill has been swallowed, it is firmly grasped by the oesophagus, allowing complete microscopic imaging of the entire wall,” said the professor.
“Other methods we have tried can compress the oesophageal lining, making it difficult to obtain accurate, three-dimensional pictures. The capsule device provides additional key diagnostic information by making it possible to see the surface structure in greater detail.”
Barrett’s oesophagus is caused by chronic exposure to acid rising up from the stomach, leading to irritation and heartburn.
Up to one in ten people with acid reflux will go on to develop Barrett’s oesophagus. They are much more likely to be men.
A few patients with the condition – about one in 100 each year in the UK – end up being diagnosed with oesophageal cancer.
Co-author Dr Norman Nishioka, also from Massachusetts General Hospital, said: “An inexpensive, low-risk device could be used to screen larger groups of patients with the hope that close surveillance of patients found to have Barrett’s could allow us to prevent oesophageal cancer or to discover it at an earlier, potentially curable stage.
“But we need more studies to see if that hope would be fulfilled.”