The large-scale deployment of low-cost, noninvasive mechanisms of early detection are needed to reduce the melanoma burden. A serial 2-step system could power mass screening efforts serving the uninsured and underinsured as well as the rural and remote US counties where melanoma mortality is doubled for lack of access to dermatologists. Furthermore, serial melanoma screening strategies, serial total body photography and serial digital dermatoscopy imaging may be performed as a telehealth service, and thus would be available in any location that can support activity compliant with the Health Insurance Portability and Accountability Act and has appropriate bandwidth.
Key points
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Lesion evolution is a cardinal sign of cutaneous melanoma (CM).
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Visual skin examination is relatively insensitive to CM, especially small lesions.
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Serial total body photography is sensitive but not specific to CM.
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Short-term serial digital dermatoscopy imaging evolution is specific to CM.
Introduction
A slow and inexorable increase in the incidence and mortality of cutaneous melanoma in the United States has been noted since 1935. Albeit small initially, it is a deadly cancer that evades traditional methods of detection. Now, in 2016, more than 10,000 people are projected to succumb to melanoma in the United States.
Limited epidemiologic evidence suggests that the traditional method of melanoma screening is better than oncology treatments for the reduction of melanoma mortality. Studies have shown that the addition of a dermatologist (screening level) service in underserved areas led to a 53% decrease in melanoma mortality, whereas adding a hospital with an oncology department led to a mere 1.9% decrease in melanoma mortality. However, there is insufficient evidence to suggest visual skin examination (VSE) for melanoma screening. Studies demonstrated a lack of sensitivity to melanoma in the hands of dermatologists and primary care physicians alike. New pathways for improved screening merit consideration.
There is a general trend away from comprehensive physical examination for lack of efficacy. Although most melanoma patients have had at least 1 medical visit in the year before their melanoma diagnosis, only 20% reported receiving a skin cancer examination during the melanoma discovery visit. More important, VSE has limited sensitivity. Dermatologists are more sensitive and specific using VSE to detect melanoma than primary care physicians, with a sensitivity and a specificity 49% versus 40% and 97% versus 86%. VSE sensitivity to small melanomas (≤3 mm) is very limited; only 2.5% of melanomas are below that threshold. VSE with or without dermoscopy may be performed in less than 3 minutes. Perhaps if melanoma screening were more sensitive to the presence of disease and incorporated into a general physical examination the epidemic would abate.
Efforts to screen with greater sensitivity such as with total body photography are currently limited to a small, high-risk population. Furthermore, melanoma screening is generally not offered to those not considered to be at high risk. Despite the availability of reimbursement for novel melanoma screening technologies, it has not taken off.
Introduction
A slow and inexorable increase in the incidence and mortality of cutaneous melanoma in the United States has been noted since 1935. Albeit small initially, it is a deadly cancer that evades traditional methods of detection. Now, in 2016, more than 10,000 people are projected to succumb to melanoma in the United States.
Limited epidemiologic evidence suggests that the traditional method of melanoma screening is better than oncology treatments for the reduction of melanoma mortality. Studies have shown that the addition of a dermatologist (screening level) service in underserved areas led to a 53% decrease in melanoma mortality, whereas adding a hospital with an oncology department led to a mere 1.9% decrease in melanoma mortality. However, there is insufficient evidence to suggest visual skin examination (VSE) for melanoma screening. Studies demonstrated a lack of sensitivity to melanoma in the hands of dermatologists and primary care physicians alike. New pathways for improved screening merit consideration.
There is a general trend away from comprehensive physical examination for lack of efficacy. Although most melanoma patients have had at least 1 medical visit in the year before their melanoma diagnosis, only 20% reported receiving a skin cancer examination during the melanoma discovery visit. More important, VSE has limited sensitivity. Dermatologists are more sensitive and specific using VSE to detect melanoma than primary care physicians, with a sensitivity and a specificity 49% versus 40% and 97% versus 86%. VSE sensitivity to small melanomas (≤3 mm) is very limited; only 2.5% of melanomas are below that threshold. VSE with or without dermoscopy may be performed in less than 3 minutes. Perhaps if melanoma screening were more sensitive to the presence of disease and incorporated into a general physical examination the epidemic would abate.
Efforts to screen with greater sensitivity such as with total body photography are currently limited to a small, high-risk population. Furthermore, melanoma screening is generally not offered to those not considered to be at high risk. Despite the availability of reimbursement for novel melanoma screening technologies, it has not taken off.
Cutaneous melanoma evolution
The most common presenting cutaneous melanoma (CM) symptom (51%) is an “increase in size.” CM arises from melanocytes in the basal epidermal layer, visible to the human eye. The detection of CMs of minute size depends on the observation of abrupt changes most easily detected through comparison of serial imaging, revealing a lesion as small as 1.5 mm. Moreover, small lesions, 1.6 mm diameter, can also be invasive.
CMs grow more rapidly than nevi in a 6- to-12 week period of follow-up. Other monitoring studies documenting observable changes in CMs over a period of months led to the addition of the letter “E” for “evolving” to the ABCD acronym to increase its sensitivity and specificity.
Unfortunately, change is obscured by the complex skin patterns of high-risk patients who have too many candidate lesions for human memory to record without imagery. For instance, most young people with melanoma under 40 years of age have an enhanced burden (>25) of nevomelanocytic lesions. Those older than 50 years at high risk have severe sun damage, rendering a pattern of autumn leaves on a lawn. Highly reproducible serial imaging is required for sensitive melanoma screening in patients with these common risk factors.
The specificity of change for the diagnosis of CM varies with risk factors. Rates of nevus change are much higher in youth, which decreases the specificity of change as a sign of disease. Conversely, evolution of a mole as a sign specific for CM increases with age. The appearance of new nevi is relatively common even in adults. The fact that most CMs arise de novo, and are not contiguously associated with a melanocytic nevus, highlights the importance of imaging the lesion free skin. The specificity of dynamic lesions is further diluted by the exponential increase in keratinocytic lesions with aging. Actinic angiogenesis also contributes to the confusion. Ultraviolet light is the most common carcinogen.
Relatively featureless CMs may be picked up at an early stage by change detection. The most relevant changes associated with CM during sequential digital dermatoscopic imaging (SDDI) are of asymmetric enlargement, an appearance of focal or eccentric new structures (ie, “dermoscopic island”), or the appearance of atypical focal dermoscopic features such as vessels or regression features. Also, CM can appear morphologically more benign over time, at least during short-term monitoring. Melanomas may even be invisible to microscopic inspection.
Serial evaluation
Serial image evaluation beyond montage comparison came of age after imagery went digital. Within the past 20 years, skin surface imaging has increasingly emphasized time lapse evaluations. A technique known as SDDI was introduced by colleagues in Austria. In the United States, the total immersion photography (TIP) array, developed in 2000, provided imagery for time lapse tracking over the entire accessible body surface.
Serial total body photography, automated by camera arrays and enhanced by serial dermatoscopy of focal changes, provides a promising sensitivity solution. This highly efficient process, featuring arrays of 25 to 46 cameras, was first introduced as TIP in 2000 with an animated flicker system to harness the eye’s motion detection as is done with serial retinal photography. The second step, digital dermatoscopy, was added in 2005 with tracking in 2007. Now, the modern 2-step process depends on sequential whole body photography and dermatoscopy ( Fig. 1 ) after a baseline examination.
Related posts:
Clinical Diagnosis of Skin Cancer
Enhancing Skin Cancer Diagnosis with Dermoscopy
Using Raman Spectroscopy to Detect and Diagnose Skin Cancer In Vivo
Proteomic Mass Spectrometry Imaging for Skin Cancer Diagnosis
Smartphone-Based Applications for Skin Monitoring and Melanoma Detection
Teledermatology Applications in Skin Cancer Diagnosis
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