Skin cancer is the most common form of cancer in Australia. With one of the highest rates in the world, it kills more than 1,850 Australians each year. The ability to identify cancerous lesions at early stages of development, when treatment is usually more effective and often curative, is vital to reducing deaths from skin cancer.
Traditionally, dermatologists have relied on visual examination of suspicious moles and lesions with the naked eye to deliberate over their possible malignancy and determine whether to proceed with a biopsy (removal of a sample of tissue for examination to diagnose a medical condition). Cancerous lesions, particularly melanomas, present with typical clinical symptoms so a specialist will look for these characteristics:
Asymmetry – moles which do not look the same on both sides
Border – the edges of lesions which are blurry or irregular
Colour – colour variation within lesions; they may be light to dark brown, black, red, white and even blue
Diameter – moles larger than 6mm across
Evolving – lesions which grow or change shape and colour
Many dermatologists use a dermatoscope, an instrument which magnifies the skin spot to allow for more detailed inspection of its structure and landscape. These tools use filters to polarise the light emitted and magnify specific aspects of a lesion, such as certain colours.
A new diagnostic being used by some specialists involves the production of detailed images of the skin in sections, a type of tomography. This tool scans the lesion and highlights particular features characteristic of tumours.
Another method currently being used to evaluate the skin is photographic devices coupled with computer databases containing volumes of skin cancer characteristics. The photographed image of the spot is enlarged on a computer then graded against hundreds of thousands of digital pictures to compare various traits and establish the likelyhood of malignancy.
Among the new technologies undergoing development is the MelaFind system, a hand-held melanoma detection device linked via the internet to a company’s server. MelaFind uses ten different light wavelengths which are scattered by the skin surface they hit, and are then collected to create the computer image. The lesion image is then cleaned up, analysed in relation to a database of lesions with algorithms and finally classified as positive or negative for melanoma. The MelaFind system is currently under review by the FDA as the latest diagnostic tool.
This is the first in a two-part blog series on skin cancer detection devices. The second post, which you can read here, discusses newer inventions still under development.
References
American Academy of Dermatology, 2010, ABCDEs of Melanoma Detection, accessed 8th March 2011, <http://www.aad.org/public/exams/abcde.html>
Cancer Council Australia, 2010, Sun Smart, accessed 8th March 2011, <http://www.cancer.org.au/sunsmart>
Medical News Today, 2008, Stop Skin Cancer On The Spot, accessed 8th March 2011, <http://www.medicalnewstoday.com/articles/129338.php>
MELA Sciences, n.d, MelaFind®, accessed 8th March 2011, <http://www.melasciences.com/>
Image reference
‘Dermatoscope1’ uploaded to Wikimedia commons by ‘Frank33’ on 19 July 2007, http://commons.wikimedia.org/wiki/File:Dermatoscope1.JPG
