Patterns of the use of reflectance confocal microscopy at a tertiary referral dermatology clinic (2021)

To the Editor: Imaging using reflectance confocal microscopy (RCM) allows noninvasive examination of the skin in real time at the bedside, with cellular-level resolution. At the Memorial Sloan Kettering Cancer Center, we have been using RCM, both the arm-mounted, wide-probe microscope (Vivascope 1500, Caliber ID) and the hand-held, portable microscope (Vivascope 3000, Caliber ID), at our dermatology and dermatologic surgery clinics since 2011.1Caliber I.D. Noninvasive cellular imaging of the skin.https://caliberid.com/clinical.htmlDate accessed: August 18, 2021Google Scholar The hand-held microscope is currently not reimbursable, and we do not bill for it.2US Centers for Medicare & Medicaid ServicesPublication CMS-1654-P.https://www.cms.gov/Medicare/Medicare-Fee-for-Service-Payment/PhysicianFeeSched/PFS-Federal-Regulation-Notices-Items/CMS-1654-PDate accessed: August 18, 2021Google Scholar RCM has been shown to improve malignancy detection, reduce unnecessary biopsies, and guide interventions or surgical procedures.3Pezzini C. Kaleci S. Chester J. Farnetani F. Longo C. Pellacani G. Reflectance confocal microscopy diagnostic accuracy for malignant melanoma in different clinical settings: systematic review and meta-analysis.J Eur Acad Dermatol Venereol. 2020; 34: 2268-2279https://doi.org/10.1111/jdv.16248Crossref PubMed Scopus (27) Google Scholar, 4Guitera P. Menzies S.W. Longo C. Cesinaro A.M. Scolyer R.A. Pellacani G. In vivo confocal microscopy for diagnosis of melanoma and basal cell carcinoma using a two-step method: analysis of 710 consecutive clinically equivocal cases.J Invest Dermatol. 2012; 132: 2386-2394https://doi.org/10.1038/jid.2012.172Abstract Full Text Full Text PDF PubMed Scopus (252) Google Scholar, 5Navarrete-Dechent C. Cordova M. Aleissa S. et al.Lentigo maligna melanoma mapping using reflectance confocal microscopy correlates with staged excision: a prospective study.J Am Acad Dermatol. December 5, 2019; (https://doi.org/10.1016/j.jaad.2019.11.058)Abstract Full Text PDF Scopus (12) Google Scholar However, these applications have not been described in a clinical practice setting. To describe the use of RCM at a tertiary referral center, we queried the Memorial Sloan Kettering Cancer Center for clinical documentation and an internal database for RCM imaging performed at the center between January 2017 and December 2020. We extracted data about the lesion site, microscope used, initial clinical concern, and, when available, RCM image and pathology report. Of 1905 lesions with a recorded initial clinical concern, melanocytic lesions comprised 46% (n = 874), basal cell carcinomas (BCCs) comprised 30% (n = 571), extramammary Paget diseases comprised 4% (n = 68), squamous cell carcinomas (SCCs) comprised 3% (n = 50), and rare or unspecified lesions comprised 18% (n = 342). Among these most commonly imaged lesions, the imaging of 30% (n = 465) was performed for margin mapping to guide surgical excision and 70% (n = 1098) to guide diagnosis. Fig 1 shows the specific RCM device used at each anatomic site. The hand-held microscope was used for 51% (n = 971) of the lesions, mostly on the ear, head or neck, oral or genital, and nose regions. The arm-mounted microscope was used for 49% of the lesions (n = 934), mostly on the upper or lower extremity and torso. Of 486 lesions for which RCM images were available, 431 lesions were one of the 3 most common lesions: melanoma, BCC, or SCC. Supplementary Table I (available via Mendeley at 10.17632/bv6fzsbct8.1). shows the clinical management of these lesions. The positive predictive value and negative predictive value was 47% and 97%, respectively, for melanoma; 50%-79% and 80%-88%, respectively, for BCC; and 31%-69% and 83%, respectively, for SCC (the ranges were a result of empirically treated lesions obscuring pathology-confirmed diagnoses). All lesions diagnosed as malignancies using RCM were biopsied or empirically treated, whereas 95%, 78%, and 73% of lesions suspicious for melanoma, BCC, and SCC, respectively, which showed benign RCM features, were spared from being biopsied. Some of these cases were still biopsied, likely because of a dermatoscopic suspicion and because RCM could not conclusively rule out malignancy. This study of the uses of RCM shows that the imaging method is used for not only diagnosis but also the surgical margin mapping of tumors. Our frequent use of the hand-held microscope, especially on uneven anatomic surfaces, suggests the need to establish new current procedural terminology codes to improve the feasibility of this technology for dermatology clinics. Of the total lesions, 73%-95% were spared from being biopsied despite an initial clinical suspicion, confirming the findings of prior studies showing that RCM minimizes biopsies and decreases morbidity. The limitations of this study include incomplete recording of data, which calls for standardization, and the evolving skills of confocal microscopists. Appreciation of RCM use in a specialized setting will help clinicians understand the value of integrating RCM into practice as the technology becomes more accessible because of reduced costs and improved billing opportunities. Dr Marghoob declares research support from Incyte and Amryt Pharma and serves on the advisory board of Alira Health. Dr Rotemberg is an expert advisor for Inhabit Brands, Inc. Dr Rajadhyaksha owns equity in Caliber ID (formerly, Lucid Inc). The Vivascope is the commercial version of an original laboratory prototype that was developed by Dr Rajadhyaksha when he was at Massachusetts General Hospital, Harvard Medical School. Drs Cordova, Chen, Halpern, Kentley, Kose, Lee, Marchetti, Markova, Navarrete-Dechent, Nehal, Rossi, Sahu, and Jain and Authors Mehta, Oh, Harris, Kurtansky, and Sun have no conflicts of interest to declare.