The principle works: a simple, inexpensive and painless light measurement on the inside of the cheek is all it takes to find out – in good time – whether there are any tumours in the head and neck area, the oesophagus or the lungs.
By the time they are discovered, cancers of the head and neck, the oesophagus and the lungs are usually at an advanced stage. At that point, therapeutic treatment is costly, intensive and, often, not very successful. The earlier you can detect a tumour, the better. Treatment is simpler, much cheaper and more likely to succeed. Arjen Amelink is a physicist and senior scientist in TNO’s Optics department. He was the project leader of a pilot study into an innovative, cost-effective and non-invasive screening method that uses light to detect tumours. The pilot study was financed by the Dutch Cancer Society (KWF)/Alpe d’HuZes fund and carried out in Rotterdam, in cooperation with the Erasmus Medical Center (Erasmus MC).
Screening for tumour growth in difficult-to-reach places
This work was inspired by an American study into bowel cancer screening, which showed that tumours developing higher up in the bowel could be detected from the rectum. This is known as the ‘field effect’. There was a chance this might also work in the digestive and respiratory tracts. The tissue lining the inside of the mouth (the buccal mucosa) is made up of cells that are very similar to those lining the oesophagus and the lungs. They all originate from the same progenitor cell. “We also know that these areas share the same risk factors for tumour formation – mainly drinking alcohol and smoking”, says Dr Amelink. “In both cases, substances are taken in through the mouth. Our theory is that, by measuring the field effect in the buccal mucosa, you can screen for tumour growth in more distant, difficult-to-reach places.”
“Calculations show that this new cancer screening method could save around two hundred to four hundred lives a year in the Netherlands”
A prism with a camera
This screening method uses light from a white halogen lamp that travels along optical fibres to the tip of a probe inserted into the mouth, where it shines into the buccal mucosa. This light is scattered by the tissue and partly absorbed. Arjen Amelink explains that “The haemoglobin in blood mainly absorbs blue and green light.” Any ‘remaining’ light is then detected by the probe. The amount and colour of this light is measured by a spectrometer. “This device works a bit like a prism with a camera behind it. It can separate white light into different colours, and measure the amount of each colour reflected by the tissue.”
Differences in the buccal mucosa
The pilot involved three groups of patients, the first with head and neck cancer, the second with oesophageal cancer and the third with lung cancer. There were twenty five patients in each group, all of whom were smokers. The screening results for these groups were compared to those from a control group of cancer-free smokers. Dr Amelink points out that “This is how we discovered differences between the buccal mucosa of cancer patients and that of cancer-free individuals. Our predictions were accurate in four out of every five cases. Eighty percent is acceptable for cancer screening. So, like the mammogram used in the national breast cancer screening programme and the stool test used to screen for bowel cancer, our method could, in theory, be used to screen for the early stages of head and neck cancer, oesophageal cancer and lung cancer.”
Saving 200 to 400 lives
Calculations show that this new cancer screening method could save around two hundred to four hundred lives a year in the Netherlands. Early detection could also generate annual cost savings of at least two million euros, as the treatment involved is less intense.
“Our theory is that, by measuring the field effect in the buccal mucosa, you can screen for tumour growth in more distant, difficult-to-reach places”
Potentially, this work could lead to a population screening programme. TNO plans to develop scenarios on how best to organize and fund a general population screening programme of this kind. Arjen Amelink asks “Should you get people to visit various centres in the Netherlands, as they do for the breast cancer screening programme? Or could the screening be done by GPs?”
TNO has still more work to do. The current screening equipment, together with all its peripheral devices, fits into a house removals box. In total, this equipment currently costs between thirty and fifty thousand euros. This means it is still too large and too expensive to be purchased by a GP’s practice. Dr Amelink says that “We should eventually be able to scale this equipment down to the size of a hair dryer”. “The next step is to redesign the screening equipment, to make it smaller and cheaper. This would make screening cost-effective. While I am cautiously optimistic that we can achieve this goal, there are still a number issues that need to be resolved.”
For more information, please contact Michiel Oderwald.