Reflectance confocal microscopy-guided carbon dioxide laser ablation of low-risk basal cell carcinomas: A prospective study

Abstract

Background: Basal cell carcinoma (BCC) treatment modalities can be stratified by tumor subtype and recurrence risk. The main limitation of nonsurgical treatment modalities is the lack of histopathologic confirmation. Reflectance confocal microscopy (RCM) is a noninvasive imaging device that provides quasihistologic images.

Objective: To evaluate the feasibility and efficacy of RCM-guided carbon dioxide (CO₂) laser ablation of low-risk BCCs.

Methods: Prospective study with biopsy specimen-proven low-risk BCCs imaged with RCM. RCM was performed on these sites before and after ablation. If residual tumor was found, a new series of laser passes were performed. The patients were then monitored for recurrence clinically and with RCM.

Results: Twenty-two tumor sites in 9 patients (5 men, 4 women) were imaged and treated. Median age was 59 ± 12.9 years (range, 30-74 years). Mean tumor size was 7.7 mm (range, 5-10 mm). Residual tumor was identified in 5 of 22 cases (22.7%) under RCM on immediate first-pass postablation sites, prompting additional laser passes. Median follow-up was 28.5 months (range, 22-32 months) with no recurrences found.

Conclusions: Addition of RCM to laser ablation workflow can detect subclinical persistent tumor after initial ablation and may serve as an aid to increase the efficacy of laser ablation.

Keywords: ablation; basal cell carcinoma; carbon dioxide laser; diagnosis; follow-up; laser; reflectance confocal microscopy; treatment.

Figure 1

Reflectance confocal microscopy appearance of aluminium chloride-highlighted basal cell carcinoma tumor nodules (white arrows), immediately after a first pass of laser ablation (no epidermis present). This patient had a second pass of laser ablation showing no residual tumor under RCM (750 × 750 µm).

Figure 2

Superficial basal cell carcinoma on the posterior shoulder of a female in her 50s with metastatic breast cancer. A. Pre-ablation reflectance confocal microscopy (RCM) image showing a suspicious cord-like structures/early tumor nodule with clefting (white arrows) and horizontal vessels (red arrows). Inlet displaying pre-ablation clinical appearance (750 × 750 µm). B. Immediate post ablation RCM showed clear-cut tumor nodules after ablation of the epidermis. These tumor nodules were highlighted by aluminium chloride (white arrow). Reticulated collagen is also seen (yellow arrow). This patient underwent 3 subsequent passes. C. A 12-month RCM follow-up showed scar with dense collagen (yellow arrows); the asterisk corresponds to a hair follicle. Insert showing the appearance of the scar (750 × 750 µm).