Confocal Microscopy–Guided Laser Ablation for Superficial and Early Nodular Basal Cell Carcinoma

Abstract

Importance Laser ablation is a rapid and minimally invasive approach for the treatment of superficial skin cancers, but efficacy and reliability vary owing to lack of histologic margin control. High-resolution reflectance confocal microscopy (RCM) may offer a means for examining margins directly on the patient. Observations We report successful elimination of superficial and early nodular basal cell carcinoma (BCC) in 2 cases-, using RCM imaging to guide Er-:YAG laser ablation. Three-dimensional (3-D) mapping is feasible with RCM-, to delineate the lateral border and thickness of the tumor. Thus, the surgeon may deliver laser fluence and passes with localized control—ie, by varying the ablation parameters in sub-lesional areas with specificity that is governed by the 3-D topography of the BCC. We further demonstrate intra-operative detection of residual BCC after initial laser ablation and complete removal of remaining tumor by additional passes. Both RCM imaging and histologic sections confirm the final clearance of BCC. Conclusions and Relevance Confocal microscopy may enhance the efficacy and reliability of laser tumor ablation. This report represents a new translational application for RCM imaging, which, when combined with an ablative laser, may one day provide an efficient and cost-effective treatment for BCC.

Confocal Imaging–Guided Laser Ablation of Basal Cell Carcinomas: An Ex Vivo Study

“…Our work, together with other studies in vivo (Tannous et al , 2003, Nori et al 2004; Scope et al, 2010; Guitera et al 2012; Pan et al, 2013; Chen et al 2014), suggests the potential possibility of peri-operative RCM imaging of superficial and early nodular BCCs to guide noninvasive diagnosis, pre-treatment detection of tumor margins, less invasive (ablative) treatment and post-treatment monitoring, directly on the patient. The ablation may be combined with other approaches such as debulking of tumor for enhancing the efficacy of treatment.…”

“…Preliminary studies in human skin ex vivo with acetic acid for nuclear contrast (Sierra et al , 2013) and in vivo with aluminum chloride (Chen et al , 2014) revealed feasibility of imaging in post-ablated tissue. However, the imaging was of variable quality.…”

Point-of-care and point-of-procedure optical imaging technologies for primary care and global health

“…These techniques can also identify spectroscopic molecular differences between tissue types, but weak autofluorescence can often require seconds of acquisition time per point. Real-time confocal microscopy, as a label-free modality, has been used to guide laser ablation of basal cell carcinoma and assess resected skin tumor and tissue specimens during Mohs surgeries, which replaces the time and expense of frequent histological processing of resected specimens (34). …”

Combined reflectance confocal microscopy-optical coherence tomography for delineation of basal cell carcinoma margins: anex vivostudy

“…Consequently, less invasive and less expensive nonsurgical alternative therapies are being increasingly developed. [11][12][13] Nonsurgical therapies can be particularly effective for minimally invasive removal of superficial and nodular BCCs, 14 which constitute about 40% (600,000 per year) of the total Mohs surgical cases. With such therapies, however, there is no tissue available for immediate pathological evaluation for the presence or clearance of tumor.…”

“…38,39 Although RCM has an inherently small field of view (FOV), usually limited to about 1 × 1 mm, larger areas can be imaged and the lateral margins of the tumor can be determined by the acquisition of video mosaics. 14,15,24 However, the penetration depth of RCM imaging is limited to 100 to 200 μm, which is not sufficient for estimating the deeper margins of BCCs. Therefore, OCT imaging, which has been proven to visualize the microanatomy of BCCs to depths of at least 1 mm, [40][41][42][43][44][45] is a complementary technology that can be used for this purpose.…”