Diagnostic accuracy of autofluorescence-Raman spectroscopy for surgical margin assessment during Mohs micrographic surgery of basal cell carcinoma

Autofluorescence (AF)-Raman spectroscopy has been shown to identify residual basal cell carcinoma (BCC) on frozen skin specimens and fresh skin specimens immediately after excision by Mohs surgery. This first diagnostic test of accuracy of AF-Raman on 130 full-face Mohs tissue layers (130 patients) shows that with improvement in tissue processing, the AF-Raman instrument is viable technique for intra-operative assessment of surgical margins

Ex vivo assessment of basal cell carcinoma surgical margins in Mohs surgery by autofluorescence‐Raman spectroscopy: A pilot study

Background: Autofluorescence (AF)‐Raman spectroscopy is a technology that can detect tumour tissue in surgically excised skin specimens. The technique does not require tissue fixation, staining, labelling or sectioning, and provides quantitative diagnosis maps within 30 min. Objectives: To explore the clinical application of AF‐Raman microscopy to detect residual basal cell carcinoma (BCC) positive margins in ex vivo skin specimens excised during real‐time Mohs surgery. To investigate the ability to analyse skin specimens from different parts of the head‐and‐neck areas and detect nodular, infiltrative and superficial BCC. Methods: Fifty Mohs tissue layers (50 patients) were investigated: 27 split samples (two halves) and 23 full‐face samples. The AF‐Raman results were compared to frozen section histology, carried out intraoperatively by the Mohs surgeon and postoperatively by dermatopathologists. The latter was used as the standard of reference. Results: The AF‐Raman analysis was completed within the target time of 30 min and was able to detect all subtypes of BCC. For the split specimens, the AF‐Raman analysis covered 97% of the specimen surface area and detected eight out of nine BCC positive layers (similar to Mohs surgeons). For the full‐face specimens, poorer contact between tissue and cassette coverslip led to lower coverage of the specimen surface area (92%), decreasing the detection rate (four out of six positives for BCC). Conclusions: These preliminary results, in particular for the split specimens, demonstrate the feasibility of AF‐Raman microscopy for rapid assessment of Mohs layers for BCC presence. However, for full‐face specimens, further work is required to improve the contact between the tissue and the coverslip to increase sensitivity

Diagnostic accuracy of autofluorescence-Raman microspectroscopy for surgical margin assessment during Mohs micrographic surgery of basal cell carcinoma

BackgroundAutofluorescence (AF)–Raman microspectroscopy is a technology that can detect residual basal cell carcinoma (BCC) on the resection margin of fresh, surgically excised tissue specimens. The technology does not require tissue fixation, staining, labelling or sectioning, and provides quantitative diagnosis maps of the surgical margins in 30 min.ObjectivesTo determine the accuracy of the AF–Raman instrument in detecting incomplete BCC excisions during Mohs micrographic surgery (MMS), using histology as the reference standard.MethodsSkin layers from 130 patients undergoing MMS at the Nottingham University Hospitals NHS Trust (September 2022–July 2023) were investigated with the AF–Raman instrument. The layers were measured when fresh, immediately after excision. The AF–Raman results and the intraoperative assessment by Mohs surgeons were compared with a postoperative consensus-derived reference produced by three dermatopathologists. The sensitivity, specificity, and positive and negative predictive values were calculated. The study was registered with ClinicalTrials.gov (NCT03482622).ResultsAF–Raman analysis was successfully completed for 125 of 130 layers and, on average, covered 91% of the specimen surface area, with the lowest surface area covered being 87% for the eyelid and the highest being 94% for forehead specimens. The AF–Raman instrument identified positive margins in 24 of 36 BCC-positive cases [67% sensitivity, 95% confidence interval (CI) 49–82] and negative margins in 65 of 89 BCC-negative cases (73% specificity, 95% CI 63–82). Only one of 12 false-negative cases was caused by misclassification by the AF–Raman algorithm. The other 11 false-negatives cases were a result of no valid Raman signal being recorded at the location of the residual BCC due to either occlusion by blood or poor contact between tissue and the cassette window. The intraoperative diagnosis by Mohs surgeons identified positive margins in 31 of 36 BCC-positive cases (86% sensitivity, 95% CI 70–95) and negative margins in 79 of 89 BCC-negative cases (89% specificity, 95% CI 81–95).ConclusionsThe AF–Raman instrument has the potential to provide intraoperative microscopic assessment of surgical margins in BCC surgery. Further improvements are required for tissue processing, to ensure complete coverage of the surgical specimens

A United Kingdom-wide study to describe resource consumption and waste management practices in skin surgery including Mohs micrographic surgery

This is the first United-Kingdom wide cross-sectional study reporting real-world data on the heterogenicity in the set-up and waste management practices of skin surgery, including Mohs micrographic surgery. Twelve participating sites from England, Northern Ireland, Scotland and Wales provided data from 115 skin surgery lists involving 495 patients and 547 skin surgery procedures between 1 March 2022 to 30 June 2022. The mean total weight of non-sharps skin surgery waste was 0.52kg per procedure (0.39kg clinical waste, 0.05kg general waste and 0.08kg recycling waste). Data from a single site using disposable surgical instruments only reported an average of 0.25kg of sharps waste per procedure. The recycling rate ranged between 0-44% across the cohort with a mean recycling rate of 16%. We advocate staff to transition to the British Society of Dermatological Surgery 2022 sustainability guidance which made wide-ranging recommendations to facilitate staff to transition to sustainability skin surgery