The MelaFind computer-based imaging system was approved by the FDA and the European Union in Fall 2011 for the evaluation of concerning pigmented lesions after selection by dermatologists. It is expected to be marketed and available this Spring of 2012. The data behind approval, role for use by dermatologists, and potential future uses are reviewed.
The incidence of malignant melanoma of the skin has been increasing over at least the past 50 years and is more than 1 in 10 among non-Hispanic whites in the US.1 The lifetime risk of diagnosis is increasing, and this trend shows no signs of abating. Against this background, interest among physicians and industry is growing for new tools to facilitate melanoma detection to increase early diagnosis and thereby increase survival rates. While skin biopsy for histologic analysis by a dermatopathologist is the gold standard for examination of pigmented lesions, interest has increased in non-invasive analysis of pigmented lesions as an alternative to biopsy.
The newest FDA-approved medical device for assessment of pigmented lesions is the MelaFind imaging system, which uses digital multispectral images in 10 spectral bands and evaluates lesions of interest compared to a computer algorithm. This system has been in development for over 10 years, and was approved by the FDA this fall with the intention of being a diagnostic aid to dermatologists for lesions of clinical concern under consideration for biopsy.
Alternatives to Skin Biopsy
The advantages of non-invasive imaging of pigmented lesions are many: no need for skin biopsy, no residual scarring, less risk of sampling bias for larger lesions because of the ability to assess multiple areas of larger lesions. As technology allows more complex decision-making at a lower cost, several types of imaging are being focused on tumors of the skin. While most focus on targeted lesions of concern, other systems take a whole-body imaging approach.
Non-Invasive Imaging Techniques
Several technologies have emerged for non-invasive evaluation of pigmented lesions. The most commonly used among dermatologists is dermoscopy, which utilizes a 10x magnifier and either polarized light or a liquid medium to cancel out skin surface reflections. This tool allows dermatologists to take a closer look at the structures of a pigmented lesion for better diagnostic accuracy; among expert dermoscopists, it does appear to improve sensitivity.
In vivo reflectance confocal microscopy is another technique to evaluate pigmented lesions without biopsy. Confocal microscopy uses a low-energy laser and computer reconstruction to view sequential layers of depth in so called ″optical sectioning,″ allowing different depths of epidermis and dermis to be examined separately. While still experimental, the pattern of regular rete ridges and regular melanocyte nests can be distinguished from the atypical junctional nests of melanoma in situ and buds of basal cell carcinoma. Confocal microscopy is undergoing clinical trials on an experimental basis to evaluate melanoma, basal cell carcinoma, squamous cell carcinoma, and common melanocytic nevi.
Full-body sequential digital imaging is another approach to pigmented lesion surveillance. While many different standards for body photography exist, attempts have been made to automate body imaging for rapid and cost-effective repeat visits. One device, MelanoScan, uses automated digital photography in a booth similar in size to a phototherapy unit. Digital imaging takes approximately 10 minutes for the entire body. The device is manufactured by a Stamford, CT company and can be purchased by dermatologists' offices. The fee for total body imaging is $150 per session and can be covered by insurances, including Medicare, if criteria such as personal history of melanoma have been met. It is generally available in the northeastern U.S. at this time.
Development and Validation of MelaFind
MelaFind is intended for use on so-called borderline lesions, that is, where a dermatologist would consider biopsy. Its imaging platform and algorithm have been developed to assess lesions of less than 6 mm on "normal" skin (other than mucous membranes, volar skin, or genital skin). It works by scanning pigmented lesions in 10 different spectral bands between blue