Adjunctive Confocal Microscopy Can Reduce Unnecessary Skin Excisions, Study Finds

Doug Brunk

June 01, 2022

Using adjunctive reflectance confocal microscopy (RCM) for examining suspect skin lesions reduced the number of unnecessary skin excisions by 43%, results from a large randomized clinical trial showed.

"Skin cancer management exerts a sizable burden on health systems," researchers, led by Giovanni Pellacani, MD, write in an article published today in JAMA Dermatology.

"The systematic application of RCM in the triage of high-risk patients should improve diagnostic accuracy and reduce unnecessary excisions for histopathological diagnostic confirmation, thereby reducing costs, surgical waiting lists, and delayed diagnoses."

However, they add, "the clinical application of RCM has mainly been limited to retrospective and prospective observational studies producing hypothetical estimates of clinical applicability without intention to affect clinical and therapeutic patient pathways."

For the current study, Pellacani, who chairs the department of dermatology at Sapienza University, Rome, Italy, and colleagues hypothesized that RCM would reduce unnecessary excisions by more than 30% and would identify all melanoma lesions 0.5 mm or thinner at baseline. They enrolled 3165 patients with suspect lesions from three dermatology referral centers between January 2017 and December 2019, with a mean follow-up of 9.6 months. Participants were randomly assigned 1:1 to standard therapeutic care, which consisted of clinical and dermoscopy evaluation with or without adjunctive RCM, a novel noninvasive technology that provides in vivo imaging of the skin, with a high diagnostic accuracy.

Histopathologic examination of all excised lesions was performed at the pathology department of the referral center. Resulting information guided prospective clinical decision-making (excision or follow-up). The mean age of patients was 49 years, 49% were women, 21% had a personal history of melanoma, and 51% had Fitzpatrick phototype 2 skin.

When compared with standard therapeutic care only, adjunctive RCM was associated with a higher positive predictive value (18.9 vs. 33.3, respectively), lower benign-to-malignant ratio (3.7:1.0 vs. 1.8:1.0), and a reduction in the number needed to excise of 43.4% (5.3 vs. 3.0). In addition, all 15 lesions with delayed melanoma diagnoses were thinner than 0.5 mm. Of these, eight were diagnosed as melanoma in situ.

Christine Ko, MD, professor of dermatology and pathology at Yale University, New Haven, Connecticut, who was asked to comment on the study, said that a strength of the analysis was its follow-up and histopathologic evaluation, "which are both essentially forms of feedback. Good, relevant feedback is necessary for all of us to improve."

She pointed out that, while RCM does appear to reduce the number of benign lesions unnecessarily removed and increase the number of skin cancers appropriately excised, the authors acknowledged that they had at least 4 years of experience with RCM. "The study also does not address the time factor (the procedure takes about 7 minutes per lesion) and the financial cost of reflectance confocal microscopy, as compared to the cost of standard follow-up alone with an increased number of excisions."

She added that the findings "are not yet applicable to general dermatology across the world, as the authors comment, given that reflectance confocal microscopy is not yet widely available."

The Italian Ministry of Health supported the study. The researchers and Ko have disclosed no relevant financial relationships.

JAMA Dermatol. Published online June 1, 2022. Full text

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