Newer technologies including total-body photography, digital dermascopy, reflectance confocal microscopy (RCM) and epidermal genetic information retrieval (EGIR) show promise as tools for improving early diagnosis of melanoma, experts say.
National report - Newer technologies including total-body photography, digital dermoscopy, reflectance confocal microscopy (RCM) and epidermal genetic information retrieval (EGIR) show promise as tools for improving early diagnosis of melanoma, experts say.
Early melanoma detection not only improves survival, but it also lowers treatment costs, "which is something we hear a lot about these days," says Laura K. Ferris, M.D., Ph.D., assistant professor of dermatology and director of clinical trials, University of Pittsburgh department of dermatology, Pittsburgh. "While less than 20 percent of our patients have stage three or four melanoma at the time of diagnosis, these patients are responsible for 90 percent of the annual treatment costs of melanoma (Tsao H, Rogers GS, Sober AJ. J Am Acad Dermatol. 1998 May;38(5 Pt 1):669-680)," she says.
An early study involving high-risk patients showed that 93 percent of melanomas found in the study population were new or changed from baseline (Feit NE, Dusza SW, Marghoob AA. Br J Dermatol. 2004 Apr;150(4):706-714). "Interestingly, patients picked up 30 percent of the melanomas using the photography. So it's not only helpful for us, but it also can help patients in their skin self-exams," Dr. Ferris says.
However, "There is some risk that we get a bit of a false sense of security when we use full-body photography. Studies have shown that we are more likely to let melanomas remain on a patient if we have the option of serial photography," she says.
Supporters of full-body photography say it has the potential to decrease biopsy rates.
"By using photography, we hope that we can save our patients with multiple dysplastic nevi from having to undergo multiple biopsies," Dr. Ferris says. But data in this regard show conflicting results, she adds.
"Another factor to keep in mind when using total-body photography is the age of the patient," Dr. Ferris says. In a study that used total-body photography to follow 309 high-risk patients, researchers found that in patients younger than age 50, less than 1 percent of all new lesions and 3 percent of changing nevi were melanomas. In patients older than age 50, the corresponding figures were 30 percent and 22 percent, respectively (Banky JP, Kelly JW, English DR, et al. Arch Dermatol. 2005 Aug;141(8):998-1006).
While older patients are at higher risk for melanoma, Dr. Ferris says, "Younger people can and will develop new and changing moles, and not all of them are melanoma. We still need to use our clinical judgment."
Meanwhile, she notes, investigators are developing computer-assisted total-body photography systems that will use the same technology used to monitor military tank movements on satellite images to automatically compare full-body images of high-risk patients taken at various visits.
Regarding dermoscopy, multiple studies show that it improves dermatologists' benign-to-malignant excision ratios. "The caveat is that we see the best results with operators who have at least five years of experience (with dermoscopy)," Dr. Ferris says. And because this technology is used less frequently in the United States than elsewhere, "We are not necessarily training everybody coming out of residency to use it," she says.
To streamline dermoscopy's learning curve, Dr. Ferris says some experts have explored computer-assisted algorithms that can distinguish between lesional and normal skin and analyze color, texture and other lesion characteristics. "Systems are commercially available now. Some make biopsy recommendations; some simply give a risk assessment of the lesion," she says.
In a proof-of-concept study involving three computer-assisted dermoscopy systems, Dr. Ferris says all three performed fairly well in identifying clinically obvious melanomas. "However, none of them outperformed dermatologists experienced in dermoscopy (Perrinaud A, Gaide O, French LE, et al. Br J Dermatol. 2007 Nov;157(5):926-933. Epub 2007 Sep 13)," she says.
Newer imaging technologies include objective multispectral computer vision, which uses multiple wavelengths of light to analyze pigmented lesions.
"Multiple wavelengths of light allow us to see multiple planes within the skin. They also allow us to visualize deeper structures than we could see even with dermoscopy," Dr. Ferris says.