Infrared imaging to grade tumour biopsies more reliably
A new technique using infrared imaging has been developed that could make grading tumour biopsies – and therefore cancer diagnosis – more accurate and reliable.
A team of scientists, led by Professor Chris Phillips from Imperial College London, published work on Digistain technology, which uses mid-infrared light to photograph biopsy tissue slices in a way that maps out the chemical changes that signal the onset of cancer.
Results from the study were published in the journal Convergent Science Physical Oncology, in which the scientists describe how their new method promises to reduce the subjectivity and variability in grading the severity of cancers.
Nearly all cancers are diagnosed by doctors taking a sample of the tumour in a biopsy. The tissue sample is sectioned and stained, and a pathologist grades the severity of the cancer under a microscope. However, different practitioners will only agree on the grade about 70 per cent of the time, which results in an overtreatment problem.
The Digistain technology measures the nuclear-to-cytoplasmic ratio (NCR), a recognised biological marker for a wide range of cancers.
Professor Phillips said: ‘Our machine gives a quantitative Digistain index (DI) score, corresponding to the NCR, and this study shows that it is an extremely reliable indicator of the degree of progression of the disease. Because it is based on a physical measurement, rather than a human judgement, it promises to remove the element of chance in cancer diagnosis.’
In the experiment reported, the team carried out a double-blind clinical pilot trial using two adjacent slices taken from 75 breast cancer biopsies. The first slice was graded by clinicians as usual, using the standard H+E protocol, which was then compared with the grade obtained by the Digistain imager.
Professor Phillips said: ‘Even with this modest number of samples, the correlation we saw between the DI score and the H+E grade would only happen by chance 1 time in 1,400 trials. The strength of this correlation makes us extremely optimistic that Digistain will be able to eliminate subjectivity and variability in biopsy grading.’
Looking to the future, the NCR factor that Digistain measures is known to be common to a wide range of cancers; it happens when the reproductive cell cycle gets disrupted in the tumour and cell nuclei get distorted with rogue DNA. It is therefore likely that Digistain will help diagnose many different types of cancer.
The Digistain imaging technology can easily and cheaply be incorporated into existing hospital labs.