Confocal reflectance microscopy reduces unnecessary excisions

According to a prospective real-life study published in JAMA Dermatology.

“The key finding is that routine use of confocal microscopy on suspicious lesions can reduce excision of benign lesions by almost 50%, with no significant loss of melanoma and zero loss of thick melanoma,” the author said. Principal Giovanni Pellacani, MD. He is Professor of Dermatology at the Sapienza University of Rome in Italy.

The investigators randomized a total of 3165 patients seen in 3 dermatology reference centers between January 2017 and December 2019 to receive standard care (clinical and dermatoscopic evaluation) with or without complementary RCM (VivaScope 1500; VivaScope GmbH).

Among 2,392 excised lesions, investigators identified 572 melanomas (23.9%), with a total number of lesions to be excised (NNE) of 4.2.1 Adjuvant RCM detected 278 melanomas, compared to 294 for usual care. However, RCM showed almost twice the positive predictive value (33.3) of usual care (18.9) and a benign to malignant ratio of 1.8:1, compared to 3.7:1 for usual care. Additionally, RCM reduced the NNE by 43.2% (3.0 versus 5.3 for standard care), exceeding a predetermined break-even point of a 30% reduction in unnecessary excisions that had been determined by a previous study.2

Of 1583 patients assigned to RCM, investigators sent 45.5% for immediate excision. Of 853 lesions referred for digital dermatoscopic follow-up (DDF), 15 (1.8%) were found to be melanoma. However, more than half of these tumors were melanomas on the spotand no melanoma found at DDF was thicker than 0.5 mm.

“We expected good results,” Pellacani said. “We were very pleased to achieve the absence of thick melanomas in the surveillance group and to have only 1.8% of lesions referred to follow-up subsequently diagnosed as melanoma.” In clinical practice, he added, about 4% of lesions referred for DDM are typically diagnosed as melanoma.

“Instead of referring to the excision of any type of lesion that you consider suspicious of melanoma,” Pellacani said, “you can get real-time, noninvasive biopsy with confocal microscopy, sparing surgery, scarring, and morbidity to the patient.”

RCM can help dermatologists decide which lesions really require excision, he said. “Obviously with confocal microscopy you have much higher precision, increasing both sensitivity and specificity.”

European guidelines recommend dermatoscopy to diagnose all pigmented and non-pigmented lesions (Level A) and suggest that RCM can be used for further evaluation of clinically or dermatoscopically equivocal lesions (Level C).3 “This study increases the evidence for its usefulness in the diagnosis of melanoma.” Every dermatologist in Italy uses a dermatoscope, he said, and RCM is readily available across Europe, with most major skin cancer treatment centers offering the technology.

In a next step, the investigators compile accurate and real data on the profitability of RCM. “It’s effective and safe,” he said. “The next question is, how much can you save by using this technology? Is it economically beneficial?” At press time, Pellacani and his colleagues had completed comparative research with several RCM systems. These results may be published later. late this year.

Simultaneously, researchers are studying how a portable RCM probe (VivaScope 3000, VivaScope GmbH) could increase the sensitivity of melanoma diagnosis, especially in difficult situations such as patients with dysplastic mole syndrome or facial macules.

The stand-alone RCM system used for the present study maps lesions through a mosaic process. The portable probe allows for faster exams, Pellacani said, but it cannot build mosaics of large fields of view. “It’s a little less precise, but we think it’s a good screening tool, to identify equivocal lesions.” Currently, the researchers are reviewing their data for possible publication in 2023.

Disclosures:

Pellacani reports no relevant conflicts of interest.

References:

1. Pellacani G, Farnetani F, Ciardo S, et al. Effect of confocal reflection microscopy for suspicious lesions on the diagnostic accuracy of melanoma: a randomized clinical trial [published online ahead of print, 2022 Jun 1]. JAMA Dermatol. 2022;10.1001/jamadermatol.2022.1570. doi:10.1001/jamadermatol.2022.1570

2. Pellacani G, Pepe P, Casari A, Longo C. Confocal reflectance microscopy as a second level examination in cutaneous oncology improves diagnostic accuracy and avoids unnecessary excisions: a longitudinal prospective study. Br J Dermatol. 2014;171(5):1044-1051. doi:10.1111/bjd.13148

3. Garbe C, Amaral T, Peris K, et al. Consensus European interdisciplinary guideline for melanoma. Part 1: Diagnostics – 2019 Update. Eur J Cancer. 2020;126:141-158. doi:10.1016/j.ejca.2019.11.014