Bowel cancer blood test closer
A prototype blood test for colorectal cancer has entered the next testing stage.
Professor Parry Guilford, who is leading the development of the test, said his team was about to start testing clinical samples from the National Bowel Screening Programme to measure the test’s efficacy.
The trial would bring them one step closure to being able to offer an affordable and easily accessible test that was also super accurate.
Guilford, the director of Translational Research (Te Aho Matatū) at the University of Otago, was in Southland last week to provide an update on his work for Hope Without Fear.
The organisation was set up by Melissa Vining and Julia Black, who both lost their husbands to bowel cancer, to help raise the $1 million needed to get through clinical trials.
Vining has long been an outspoken advocate for colonoscopy services after her late husband struggled to access one when he needed it. This led to the couple founding the Southland Charity Hospital to provide colonoscopies to people living in Southland and Otago.
Faecal testing currently used for screening produced a lot of false positives, and blood tests could be used to confirm the probability of cancer before referring patients for a colonoscopy, helping patients get answers faster. So far, Hope Without Fear had raised enough to employ a post-doctoral researcher who “just got stuck into the job,” Guilford said.
He stressed that the project leaned heavily on international research and that the Nanopore technology it used was evolving rapidly.
The blood test would look for circulating tumour DNA, or fragments of DNA that had leaked from the cancer into the bloodstream.
While cancerous tissue looked very similar to healthy tissue, there were mutations in key cancer genes.
The test would look for eight mutations that occurred in virtually all people with bowel cancer. “You don’t get some mutations in cancer genes without some mischief going on,” Guilford said.
The accuracy of the test would be crucial, he said.
“Generally in diagnostics, sensitivity is not as hard [to produce] as specificity.”
A test that produced too many false positives would just put a burden on the health system, Guilford said.
While the current prototype was labbased; the idea was to eventually make it small, simple and affordable enough to be used in smaller centres, such as medical centres or the Southland Charity Hospital.
Guilford and his team were aiming to make the test publicly available within four to five years.