Diagnostic Accuracy of Digital Staining ex vivo Confocal Microscopy for Diagnosing and Subtyping Basal Cell Carcinoma in Fresh Pretherapeutic Punch Biopsies: A Monocentric Prospective Study

Blanche Bergeret; Farzaneh Masset; Yona D Bekoy; Pascal Roger; François Habib; Bernadette Ovtchinnikoff; Laurent Meunier; Pierre E Stoebner

doi:10.1159/000524349

Diagnostic Accuracy of Digital Staining ex vivo Confocal Microscopy for Diagnosing and Subtyping Basal Cell Carcinoma in Fresh Pretherapeutic Punch Biopsies: A Monocentric Prospective Study

Dermatology. 2022 May 5:1-7. doi: 10.1159/000524349. Online ahead of print.

Authors

Blanche Bergeret^{1

2}, Farzaneh Masset³, Yona D Bekoy⁴, Pascal Roger^{2

3}, François Habib¹, Bernadette Ovtchinnikoff¹, Laurent Meunier^{2

5}, Pierre E Stoebner^{1

2

6}

Affiliations

¹ Department of Dermatology, CHU Nîmes, Nîmes, France.
² Faculty of Medicine, Montpellier University, Montpellier, France.
³ Department of Anatomopathology, CHU Nîmes, Nîmes, France.
⁴ Department of Biostatistics, Epidemiology, Public Health and Innovation in Methodology (BESPIM), CHU Nîmes, Nîmes, France.
⁵ Department of Dermatology, CHU Montpellier, Montpellier, France.
⁶ Institut de Recherche en Cancérologie de Montpellier, INSERM U1194, Montpellier, France.

PMID: 35512658
DOI: 10.1159/000524349

Abstract

Background: Ex vivo confocal microscopy using fusion mode and digital staining (EVCM) scans unfixed fresh tissue and produces rapidly digitally stained images of very similar quality to classical pathology. We investigated whether EVCM could represent an alternative to the standard histological examination of the pretherapeutic basal cell carcinoma (BCC) punch biopsies.

Objectives: The objective of the study was to assess diagnostic accuracy of EVCM versus traditional histopathological examination for diagnosing and subtyping clinically suspicious lesions of BCC in 3-mm fresh and nonfixed punch biopsies.

Methods: In this prospective monocentric observational study, patients with clinically suspected BCC were consecutively enrolled. Punch biopsies were imaged using EVCM and subsequently processed for standard histologic examination (gold standard). EVCM images were examined by a dermatopathologist blinded to clinical aspect of the lesion and histopathological results. Concordance between the EVCM and histology analysis was calculated with Cohen's kappa (κ) statistic.

Results: Sixty-six patients were recruited, and 106 biopsies were analyzed. EVCM correctly diagnosed 70/73 BCCs and 31/33 non-BCC lesions, corresponding to a sensitivity of 96% and a specificity of 94% (positive predictive value = 97%, negative predictive value = 91%). The EVCM assessment led to over-staging and under-staging of BCC subtypes in 5% and 11% of cases, respectively. It led to over-staging and under-staging of BCC depths in 5% and 15%, respectively. The kappa coefficient for concordance was 0.78 (95% confidence interval [CI]: 0.69-0.88) when considering BCC subtypes and 0.81 (95% CI: 0.72-0.90) when considering BCC depths.

Conclusions: These results render EVCM as a promising option for "real-time" pretreatment evaluation of clinically suspected BCC lesions. Further larger randomized studies are needed to assess the efficiency of EVCM versus standard care in patients with clinically suspected BCC.

Keywords: Basal cell carcinomas; Biopsy; Digital staining; Ex vivo confocal microscopy.