Page 9 - Noninvasive Diagnostic Techniques for the Detection of Skin Cancers

Background

Cancers of the skin are the most common forms of cancer in men and women, and account
for nearly half of all malignancies. In 2009, more than 1 million cases were expected in the
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United States. Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), two types of
nonmelanomatous lesions associated with aging and sun exposure, are responsible for more than
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800,000 cases per year. Recent studies have also linked nonmelanoma skin cancer (NMSC) to
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prior cancer therapy, especially radiation therapy. While NMSC is rarely lethal, these lesions are
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associated with other malignancies (including hematologic and respiratory tract cancers). In
contrast, melanoma accounts for approximately 4 percent of all skin cancer cases, but causes the
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majority of skin cancer deaths. One study found that melanoma incidence rates had doubled in
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all socioeconomic groups over a 10-year period. Another study found that melanoma incidence
rates have increased by 3 percent per year in white Hispanic and white non-Hispanic
populations, and both white Hispanic and Black populations had more advanced disease at
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presentation. Melanoma is associated with significant morbidity, and late stage melanoma with
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significant mortality due to the likelihood of metastatic spread.
Therefore, timely diagnosis and treatment are critical to reducing rates of morbidity and
mortality of all skin cancers. However, suboptimal diagnostic accuracy of current methods of
lesion assessment (such as visual inspection) may lead to misleading false positives or
conversely missed diagnoses, and the existing protocol of excisional biopsy of suspected lesions
is an invasive, costly, and time-intensive procedure. Newer noninvasive screening and diagnostic
modalities are available that may provide more precise imaging of suspected lesions and more
accurate detection, thereby improving in vivo diagnosis. These newer technologies may,
therefore, assist with earlier detection, eliminate unnecessary biopsies, and reduce costs and
patient time spent in the physician’s office.

Current and Emerging Modalities of Assessment and

Diagnosis

Several groups in Europe, North America, Australia, and New Zealand have developed
guidelines for the screening and prevention of skin cancer. 9-12 According to a 2009 Guideline
Synthesis, while there is general agreement that there is insufficient evidence to support
screening of the general population for skin cancer, increased surveillance for individuals at
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higher risk is generally recommended.
According to Goodson 2009, most dermatologists would agree that the goals of monitoring
of nevi and detection of melanoma include the identification of high-risk patients, early biopsy of
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suspected melanomas, monitoring of nevi, and the avoidance of unnecessary biopsies. High-
risk patients in the case of melanoma include those patients with a personal history of melanoma,
family history, suspicious skin lesions (e.g., atypical nevi), and other risk factors (e.g., age ≥50
years, prior history of cancer). For patients with suspected SCC or BCC, a goal of management
is to reduce potentially disfiguring biopsies.
The assessment of suspicious skin lesions typically begins with a physical examination and
visual inspection of the skin with the naked eye. Full body and digital photography, which
augments visual inspection, are used across different practice settings and specialty groups. In
addition, many dermatologists use dermoscopy (also known as dermatoscopy, epiluminescence
microscopy, or surface microscopy) to better examine the lesion. The dermoscope is a

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