By David Douglas
NEW YORK (Reuters Health) - Reflectance confocal microscopy (RCM) can provide effective noninvasive cellular assessment of skin lesions suspected of being cancerous, according to two new studies.
Dr. Alon Scope, co-author of an accompanying editorial, told Reuters Health by email the new technology "is fundamentally changing the way we diagnose skin cancer. We can now image the cells that make up a skin lesion, without cutting into the skin's surface, and determine more precisely if the lesion is malignant."
Importantly, added Dr. Scope of Tel Aviv University, Israel, "this 'optical biopsy' can spare many benign skin lesions from the surgical knife, and is thus useful for diagnosing lesions on cosmetically sensitive areas like the face."
Both reports were published online August 31 in JAMA Dermatology.
In the first, Dr. Caterina Longo of Arcispedale Santa Maria Nuova-IRCCS Reggio Emilia, Italy, and colleagues describe their prospective evaluation of a total of more than 1,200 equivocal skin lesions in 1,147 patients referred for RCM imaging.
RCM's main application was in deciding whether a given lesion should be biopsied. Overall, 52.2% of these lesions were excised after RCM evaluation to rule out skin cancer. The remaining lesions, which were not excised, were deemed benign after a year of follow-up.
RCM had a sensitivity of 95.3% and a specificity of 83.9%. The approach, say the researchers, was "most useful for lesions located on the head and neck, lesions with clinical evidence of sun damage, and those with evidence of regression on dermoscopy."
Dr. Longo told Reuters Health by email, "Our study highlights the role of confocal microscopy in clinical real practice: in particular, it emphasizes the best clinical situations for which a dermatologist not equipped with RCM could refer the patient to a tertiary center for confocal evaluation."
In the second study, Dr. Thaís Corsetti Grazziotin of Universidade Federal de Ciências da Saúde de Porto Alegre, Brazil, and colleagues retrospectively examined use of RCM in morphologic patterns of melanomas in multiple primary and familial melanomas.
"Specific phenotypic features of high-risk patients were associated with dendritic-cell and round-cell type melanomas upon confocal microscopy classification," Dr. Grazziotin told Reuters Health by email.
The team examined 57 melanomas from 50 patients. Among the most prevalent were dendritic-cell (40%) and round-cell (37%) melanomas. Nine (16%) were unclassifiable.
Patients with dendritic-cell melanoma were a mean of 10.5 years older than patients with round-cell melanoma. They were also characterized by phototype 2 and 3 disease, more intense solar exposure, and moderate to severe solar lentigines.
Round-cell melanomas were identified more often in a familial context (61.9%) than dendritic-cell melanomas (34.8%). Phototype 1 was also more prevalent (24% versus none).
No significant association was found between the presence of CDKN2A mutations and a specific confocal melanoma type. Thus, say the researchers, "CDKN2A mutation carriers may develop any RCM type of melanoma."
"Future studies are necessary to enhance our knowledge of the interaction of multiple coexisting causal factors that drive melanoma development," they conclude.
Dr. Scope and Michael Marchetti of Memorial Sloan Kettering Cancer Center, New York, say in their editorial that there is a bright future ahead for noninvasive imaging and diagnosis in dermatological practice.
However, they add, "Randomized clinical trials with longer follow-up periods are needed to best estimate the impact of RCM on diagnostic accuracy, costs, and potential for overdiagnosis and misdiagnosis."
SOURCE: https://bit.ly/2bYRmRa, https://bit.ly/2cKVzZR and https://bit.ly/2cI3QtN
JAMA Dermatol 2016.
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