Optical coherence tomography versus punch biopsy for diagnosis of basal cell carcinoma: a multicentre, randomised, non-inferiority trial.

BACKGROUND: Punch biopsy is the gold standard for diagnosis and subtyping of basal cell carcinoma. The aim of this study was to assess whether use of optical coherence tomography (OCT), a non-invasive imaging tool, might avoid the need for biopsy. METHODS: In a multicentre, randomised, non-inferiority trial, patients (aged ≥18 years) with an indication for biopsy of a suspected basal cell carcinoma outside the H-zone (high-risk zone) of the face were randomly assigned (1:1) to receive either OCT or punch biopsy (regular care) via a web-based randomisation system. Patients were enrolled from three participating centres in the Netherlands: Maastricht University Medical Centre+, Catharina Hospital Eindhoven, and Zuyderland Medical Centre Heerlen. Stratification factors for randomisation were participating centre and the grade of clinical basal cell carcinoma suspicion (high vs low). The primary endpoint was the proportion of patients free from a recurrent or residual lesion (malignant or premalignant) 12 months after treatment. Modified intention-to-treat and per-protocol analyses were conducted, with a predefined non-inferiority margin of -10%. This trial is registered with ClinicalTrials.gov number, NCT03848078, and is complete. FINDINGS: Between Feb 25, 2019, and Sept 2, 2020, 598 patients were enrolled and randomly assigned to either the regular care group (n=299) or the OCT group (n=299). Data on the primary endpoint were available in 553 patients (n=268 in the regular care group, n=285 in the OCT group). After median follow-up of 12·7 months (IQR 11·2-14·1) in the OCT group and 12·6 months (10·8-14·3) in the regular care group, 253 (94%) of 268 patients in the OCT group and 266 (93%) of 285 patients in the regular care group were free from recurrent or residual lesions (malignant or pre-malignant) 12 months after treatment. According to our modified intention-to-treat analysis, the absolute difference (OCT vs regular care) was 1·07% (95% CI -2·93 to 5·06; one-sided p=0·30), with the lower limit of the 95% CI not exceeding the predefined non-inferiority margin of -10%. Per-protocol analyses led to proportions free from a residual or recurrent lesion (premalignant or malignant) of 95% (250 of 263) in the OCT group and 94% (262 of 278) in the regular care group, and an absolute difference of 0·81% (95% CI -2·98 to 4·60; one-sided p=0·34). INTERPRETATION: OCT-guided diagnosis and treatment of basal cell carcinoma is non-inferior to regular care punch biopsy. Implementation of OCT for diagnosis of basal cell carcinoma could reduce the number of consultations and invasive procedures. FUNDING: The Netherlands Organization for Health Research and Development and Maurits en Anna de Kock Stichting.

Topical Application of Glycerol Increases Penetration Depth of Optical Coherence Tomography in Diagnosis of Basal Cell Carcinoma.

Optical coherence tomography is a non-invasive imaging technique that enables high-resolution in vivo imaging of skin. Although optical coherence tomography is promising for diagnosing basal cell carcinoma, its limited penetration depth may impede basal cell carcinoma subtyping. This study evaluated whether topical application of glycerol can increase penetration depth and improve the image quality and visibility of characteristic features of basal cell carcinoma. A total of 61 patients with a total of 72 basal cell carcinomas were included. Optical coherence tomography scans were obtained before and after application of an 85% glyce-rol solution. The mean penetration depth of each optical coherence tomography scan was acquired by automatically tracing both skin surface and the point of signal loss using a custom-made MATLAB program. Mean ± standard deviation penetration depth increased from 883 ± 108 to 904 ± 88 µm before and after glycerol application, respectively (p = 0.005). Topical application of glycerol leads to a significant 2.4% increase in penetration depth. However, no significant differences in image quality and visibility of basal cell carcinoma features were found.