Dermoscopy better at diagnosing melanoma than visual inspection alone
Dermoscopy - a technique using a handheld device to zoom in on a mole and the underlying skin - is better at diagnosing melanoma than visual inspection alone, is finding of a summary of Special Collection of Cochrane Systematic Reviews.
A team of over 30 researchers and expert advisors analyzed a suite of eleven systematic reviews assessing the accuracy of different diagnostic tests to support clinical and policy-related decision making in the diagnosis of all types of skin cancer.
Early and accurate detection of all skin cancer types is essential for its appropriate management, reduction of morbidity, and improvement in survival rates. The aim of the review was to provide the world’s best evidence for how the endemic type of cancer should be identified and treated.
This is a special collection of Cochrane systematic reviews on the accuracy of tests used to diagnose skin cancer.
“We have found that careful consideration should be given of the technologies that could be used to make sure that skin cancers are not missed, at the same time ensuring that inappropriate referrals for specialist assessment and inappropriate excision of benign skin lesions are kept to a minimum,” said Dr. Jac Dinnes at the University of Birmingham who led the team of researchers.
Key findings of the Special Collection were:
- Visual inspection using the naked eye alone is not good enough and melanomas may be missed.
- Smartphone applications used by people with concerns about new or changing moles or other skin lesions have a high chance of missing melanomas.
- When used by specialists, dermoscopy - a technique using a handheld device to zoom in on a mole and the underlying skin - is better at diagnosing melanoma than visual inspection alone, and may also help in the diagnosis of BCCs.
- Dermoscopy might also help GPs to correctly identify people with suspicious lesions who need to be seen by a specialist.
- Dermoscopy is already widely used by dermatologists to diagnose melanoma but its use in primary care has not been widely evaluated therefore more specific research is needed.
- Checklists to help interpret dermoscopy might improve the accuracy of diagnosis for practitioners with less expertise and training.
- Teledermatology - remote specialist assessment of skin lesions using dermoscopic images and photographs - is likely to be a good way of helping GPs to decide which skin lesions need to be seen by a skin specialist but future research needs to be better designed.
- Artificial intelligence techniques, such as computer-assisted diagnosis (CAD), can identify more melanomas than doctors using dermoscopy images. However, CAD systems also produce far more false positive diagnoses than dermoscopy and could lead to considerable increases in unnecessary surgery.
- Further research is needed on the use of specialist tests such as reflectance confocal microscopy (RCM) – a non-invasive imaging technique, which allows a clinician to do a ‘virtual biopsy’ of the skin and obtain diagnostic clues while minimizing unnecessary skin biopsies. RCM is not currently widely used in the UK but the evidence suggests that RCM may be better than dermoscopy for the diagnosis of melanoma in lesions that are difficult to diagnose.
- Other tests such as using high-frequency ultrasound have some promise, particularly for the diagnosis of BCCs, but the evidence base is small and more work is needed.
The researchers warrant the need that future studies evaluating diagnostic skin cancer tests should recruit patients with suspicious skin lesions at the point on the clinical pathway where the test under evaluation will be used in practice.
Moreover, research is also needed to evaluate whether checklists to assist diagnosis by visual inspection alone can improve accuracy and identify how much accuracy varies according to the level of expertise of the clinician carrying out the assessment.
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