Pre-cancer stage is a focus of early detection initiative
New approaches are being developed that could eventually help doctors to pick out and treat unusual growths on the bowel wall, writes CLAIRE O'CONNELL
“There’s a huge amount of evidence to say that if you it early, at the pre-cancer stage, and you remove it, then you reduce the incidence of cancer, and that’s the whole basis of the screening programmes,” says Dr Paul Neary, a consultant colorectal surgeon at Tallaght hospital and a senior lecturer at the Royal College of Surgeons (RCSI) and Trinity College Dublin.
He notes that new approaches are being developed that could eventually help doctors pick out and treat unusual growths on the bowel wall: “The technology that is coming onstream is phenomenal.” One diagnostic test that stands to benefit from new technologies is the colonoscopy, where a camera is passed through the back passage using an endoscope and guided through the emptied bowel to look for unusual growths or features.
Neary is involved in the development of an imaging technique to help make abnormalities appear more obvious during endoscopy by splitting out different wavelengths of light to analyse the gut wall.
“The huge advantage is that a lot of lesions like polyps are easy to see, but some of them are flat and sometimes you can miss them as you go by with your colonoscope due to the presence of faecal matter,” he explains.
The project, which involves the University of Limerick, the National Biophotonics and Imaging Platform and RCSI, is looking to marry the imaging software to regular endoscopy to improve the pick-up of unusual features in the bowel.
“No matter what test you do, there will be a miss rate and there would be abnormalities you might miss on endoscopy no matter how good you are. So this may be a safety net or even augment the detection of abnormalities of the colon,” says Neary.
Building more powerful and smaller light sources to help seek out the cancer is also a priority, and RCSI is working with Tyndall National Institute to develop LED-based lighting systems for endoscopes, he adds.
Another approach to detecting bowel cancer is the “virtual colonoscopy”, where a person has a CT scan to build up an image of their colon, and a group at Dublin City University has developed software to analyse the resulting images and highlight the polyps.
“We can look at polyp size and we can pop up a three-dimensional drawing that you can rotate around the screen and use calipers to measure them if you want,” says Paul Whelan, professor of computer vision at DCU’s school of electronic engineering. “And the system that we developed produces a report too saying where the polyps are.”
In head-to-head tests, the software stacked up well against the experienced human eye, according to Whelan. “With radiology you tend to have two readers to make sure you don’t miss anything. This could act as a second reader effectively, if the FDA approve it,” he says.
Their computer-assisted approach can work even where relatively low doses of radiation have been used to generate the image, notes Whelan. “As low as you can turn the dial on the scanner, we can still work on that.” DCU has just licensed the technology to UK company Biotrinics3D, and the hope in the field is that the computer-aided detection approach will soon get approval for more widespread use. Meanwhile, an innovative project at the Cork Cancer Research Centre has developed a device that can attach to a conventional endoscope and zap anti-cancer drugs into bowel tumours in situ to shrink them.
Tumours don’t normally like to admit large-weight molecular drugs, but the device helps open the cellular gates by delivering microsecond pulses to the cancerous tissue, explains Dr Declan Soden, who invented the device.
“If you pulse the tumour tissue you make it leaky and porous and the drug can get in through diffusion,” he says.
The “electroporation” approach has proven its mettle on skin cancers previously, and pre-clinical work on bowel cancers with the new device has also shown promise, according to Soden. An early stage clinical trial is now open in Cork for suitable patients, and the group plans to extend the trial to other centres around the country if the initial phases pan out well, he adds.
2,216:new cases of bowel cancer were diagnosed in Ireland 2008
1,286:new cases in males and
930:new cases in females
The Irish Cancer Society, in association with the Bowel Cancer Support Group, is hosting a national Bowel Cancer Seminar on Saturday, April 24th in the O’Callaghan Davenport Hotel, Dublin 2. For details or to register for your free place, contact Eleanor on 01-2310518 or e-mail firstname.lastname@example.org