Page 37 - Noninvasive Diagnostic Techniques for the Detection of Skin Cancers

Summary
In this brief, a single RCT of PDD was found in which the technical aspects of method were
explored. Much of the extant literature addresses the technical aspects of the photosensitizers or
the available different light sources. Although the available literature addresses the potential
benefit of this method in directing or limiting potentially disfiguring biopsies for patients with
nonmelanomatous skin lesions, there is little to no evidence to support the use of this method in
melanoma given current data on test accuracy. Information about training requirements or
optimum clinical setting was also not identified.

Investigational Devices

Multiphoton Laser Scanning Microscopy
Multiphoton laser scanning microscopy, also known as multiphoton fluorescence microscopy
or multiphoton excitation microscopy, uses more than one photon excitation to illuminate
endogenous fluorophores in skin tissues, which emits a fluorescence signal to be captured by a
detector. 122 Similar to CSLM, it uses laser beam and allows imaging of tissues beyond the
superficial epidermis. Unlike CSLM, this technique does not use a confocal pinhole filter. 123,124
Evidence of the current application of this modality is sparse. Our systematic literature search
identified three narrative reviews and two diagnostic studies of multiphoton microscopy or
tomography (see Appendix D, Table D1).
We identified two registered cross-sectional studies that assess the use of this technology for
skin lesion evaluation. Both studies are based in Taiwan and are recruiting participants (see
Appendix C, Table C2). The only commercially available device for multiphoton tomography is
®
DermaInspect , manufactured by JenLab in Germany (jenlab.de/DermaInspect-R.29.0.html). We
could not determine the FDA clearance status for this device on the FDA CDRH database (see
Appendix C, Table C1).

Electrical Bio-Impedance
Different biological tissues have different electrical impedance spectra. The spectrometer
measures impedance in different frequencies (1 to 1000 kHz) as different frequencies reflect
different tissue properties. Skin electrical impedance has been found to be statistically different
depending on tissue types (e.g., impedance of benign pigmented nevi has been shown to be
different from basal cell carcinoma). 125 One group of authors reported using the SciBase I
noninvasive electrical impedance spectrometer (SciBase AB, Huddinge, Sweden) to measure
impedance of different skin lesions. The use of electrical bio-impedance in the detection of skin
cancer remains investigational at this time. The five abstracts on bio-impedance that we
identified were all published before 2006 (see Appendix D, Table D1).
A proposed advantage of bioelectrical impedance is that the data generated from this
technology can complement information from visual inspection, and help prevent misdiagnosis
of basal cell carcinoma and other types of skin cancer. 126 Even though statistically significant
differences in impedance were found between tissue types in Aberg 2003, 125 the degree of
overlap and within group variance were too high to allow for easy clinical differentiation based
on impedance measurements.
A search of the ClinicalTrials.gov Web site (accessed November 3, 2010) identified an
international, prospective, non-randomized study that collected data for optimization of an
algorithm to classify skin lesions using electrical impedance. This study has been completed, but

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