A novel imaging technology, developed by researchers from Imperial College London (UK), could revolutionize how tumor biopsy is graded. The technology, termed ‘digistain’, was recently described in the journal Convergent Science Physical Oncology.
Currently, almost all cancers are diagnosed by excised biopsy specimens whereby the severity of the disease is judged by eye alone through the microscope. It is well known that different practitioners given the same biopsy will only agree on its grade about 70% of the time, resulting in an over treatment problem.
Digistain technology works by utilizing mid-infrared light to map the fractional concentration of nucleic acids i.e. the nuclear-to-cytoplasmic chemical ratio, a recognized biological marker for a wide range of cancers.
“Our machine gives a quantitative ‘Digistain index’ (DI) score, corresponding to the nuclear-to-cytoplasmic chemical ratio, and this study shows that it is an extremely reliable indicator of the degree of progression of the disease, ” lead author Chris Phillips, from Imperial College London, explained.
In this initial double-blind clinical pilot trial, two adjacent slices were obtained from 75 breast cancer biopsies. One was graded with the standard H + E protocol and used to define a ‘region of interest’. Digistain was then used to acquire a DI value averaged over the corresponding ‘region of interest’ on the other (unstained) slice and the results were statistically analysed.
The team demonstrated that the DI score correlates significantly (p=0.0007) with tumor grade in a way that promises to significantly reduce the inherent subjectivity and variability in biopsy grading.
“Because it is based on a physical measurement, rather than a human judgement, it promises to remove the element of chance in cancer diagnosis,” he added.
At a practical level, the researchers state that the Digistain imaging technology can easily and cheaply be incorporated into existing hospital labs and be used by their staff.