This week the New England Journal of Medicine (NEJM) published an article by researchers from Wisconsin who evaluated sensor technology to assess clinical skills. They sought to understand if a force sensor could provide insight for the performance of clinical breast examination (CBE). They recruited 553 physicians – breast surgeons, family doctors and gynaecologists – at their annual congresses and tested them using four models of the breast. Each model employed a sensor to measure applied force and incorporated an embedded mass to simulate breast lesions, two superficial and two deep.
Most physicians had little difficulty correctly identifying the lesions near the surface of the breast (A and B), whereas those who pressed with a force of less than 10 newtons were at significant risk of missing deep-tissue masses (C and D). Click on the graph at right (© NEJM) to see their results in greater detail. They concluded that their findings underscored “the potential of sensor technology to add value to existing, observation-based assessments of clinical performance.”
Dr Frank Hoffmann is a gynaeclogist based in Duisburg, Germany who had a eureka moment while standing in his shower: Could a blind woman do a better job than him in identifying breast cancer when conducting a CBE? The idea that blind people might detect tumours earlier than their sighted counterparts had in fact been around for a few years, but Hoffman took the initiative to explore the idea further. He established an organisation, Discovering Hands, and devised a course to train blind women to become Medical Tactile Examiners (MTEs).
There are now 17 qualified MTEs working in gynaecology practices across Germany who appear to be making a real difference. In a study conducted by the University of Essen, but not yet published, blind women detected nearly a third more lumps than trained gynaecologists. According to Hoffmann, “Women doing self-examinations can feel tumours which are 2 cm and larger. Doctors can find tumours between 1 and 2 cm, whereas our MTEs find lumps between 6 and 8 mm. The difference in size is the time it takes a tumour to spread its cells into the body.”
Although Gerd Gigerenzer of the Max Planck Institute is skeptical about the benefits, one of Hoffmann’s patients says she owes her life to the MTE who diagnosed a small lump, just 2 mm in size that did not show up on either X-ray or ultrasound. Meanwhile, Discovering Hands is now looking to expand into Austria, Israel and Columbia.
So the ability to feel a lump in a breast depends on:
1. Force exercised by the fingers (should be pressure)
2. Stiffness of the tissue and the difference in stiffness between normal tissue and tumour.
3. Distance between lesion and skin (size of breast and the location of the tumour)
4. Experience (whether you are blind or not)
A test with potentially a lot of noise, but not worse than mammography in Canada 1980 (Miller BMJ)!
It puts “symptomatic “and “non-symptomatic” in perspective.
Almost every tumour is more stiff and for that reason symptomatic, if you can come close enough.