Jeff Craven/MDedge News
Dr. Darrell S. Rigel
“If you incorporate the data from these devices into the biopsy decision, you can improve biopsy sensitivity and accuracy of selection. I think there’s no question with these technologies that’s a true statement,” said Dr. Rigel, of New York University Langone Health.
When considering diagnostic devices, evaluate whether they produce results that outperform dermatologists, are low cost, user-friendly, time-efficient and have a high sensitivity and specificity, Dr. Rigel advised. But since no device has a perfect sensitivity and specificity, they cannot be followed blindly. The data from these devices should be used to inform, but not replace, clinical decisions made by dermatologists.
“They’re basically additional information to integrate into the biopsy decision,” he said. “At the end of the day, if you see something with a low score but it really looks funky, the reality is you have to really consider it for biopsy.”
Dr. Rigel discussed five device types that were used to analyze a number of preselected, noninvasive melanoma lesions. The devices required little training to use and a dermatologist would be required to correctly identify the lesions in a deeper analysis.
- Multispectral digital skin lesion analysis (MDSLA) uses 10 spectral wavelengths to measure the light reflected from the tissue, generating a score from a proprietary algorithm that predicts the risk of melanoma. Use of MDSLA improved the biopsy sensitivity for melanoma from 65% to 93% among 179 dermatologists who reviewed images of 24 lesions, 5 of which were melanoma (Arch Dermatol. 2012;148(4):541-3).
- Spectrophotometric intracutaneous analysis scope uses a similar analytic method as the MDSLA device but is difficult to find in the United States; however, one recent study cited a sensitivity of 81.4% and a specificity of 86.4%, indicating it has value for diagnosing melanoma.
- Raman spectroscopy uses monochromatic laser light to analyze the vibratory patterns of cells and examines the shifts in the light to identify a “molecular fingerprint” of potentially cancerous cells, has a high sensitivity and a “relatively reasonable specificity,” Dr. Rigel said.
- Elastic scattering spectroscopy, a newer technology that uses a smartphone-sized device to measure the difference in light scattered from different cellular structures, holds promise to reduce the number of negative biopsies when differentiating between malignant and benign skin conditions. It is currently pending approval with the Food and Drug Administration.
- Electrical impedance spectroscopy (EIS), which uses an electrical alternating current to detect the electrical resistance of potentially cancerous tissue, generates a score with a high negative predictive value and a higher positive predictive value as the score increases. In a study of melanoma diagnoses made by dermatology trainees, use of EIS decreased the number of missed melanomas by 23.4% and resulted in fewer benign biopsies. (J Amer Acad Dermatol. 2019;80:285-7).
All these technologies have been proven effective, but have encountered various economic roadblocks, including delays in regulatory approval, which are partly responsible for why some are no longer on the market, Dr. Rigel said. “If you have to wait 5 years or 7 years to get approval of these devices, by the time they’re approved, the technology is already passed by.”
There are also issues with reimbursements, Dr. Rigel noted, which can further reduce the clinical implementation of these technologies.
Dr. Rigel reported relationships with Derm Tech International, Scibase (maker of EIS) and a number of dermatologic drug companies.