Nonablative laser therapy is emerging as an effective noninvasive treatment option for basal cell carcinoma (BCC) with reduced adverse effects and good cosmetic outcomes compared to surgery. Vascular lasers, such as the pulsed dye laser (PDL), are thought to work by selectively targeting the tumor’s vascular network while preserving normal surrounding tissue.1,2 Although high energy and multiple passes might be required, adjunctive use of dynamic cooling reduces the risk for nonselective thermal injury vs ablative lasers, which destroy the tumor itself through vaporization of tissue water.2
With no established laser management guidelines for the treatment of BCC, earlier studies using a 595-nm PDL varied highly in their protocol.3-8 Pulsed dye laser parameters ranged from a spot size of 7 to 10 mm, fluence of 7.5 to 15 J/cm2, and pulse duration of 0.5 to 3 milliseconds. Follow-up ranged from 12 days to 25 months after the final laser treatment. The number of lesions in prior studies ranged from 7 to 100 BCCs, with the clinical clearance rate ranging from 71.4% to 75% for facial BCC and 78.6% to 95% for nonfacial BCC.3-8 Studies with histologic confirmation had a clearance rate of 66.6% for facial BCC and 25% to 92.3% for nonfacial BCC.3-5,7,8 Most studies examined BCCs on the trunk and extremities with few investigating facial BCC,3-8 which is especially important given that the head and neck are the most common and cosmetically sensitive anatomic locations.9-13
Noninvasive imaging devices, such as reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) can assist with the diagnosis and treatment monitoring of BCC. These devices enable in vivo visualization of tissue in both cross-sectional and en face views and therefore can reduce the need for diagnostic biopsy. Reflectance confocal microscopy enables near-histologic visualization of the epidermis and superficial dermis with a resolution of 0.5 to 1 μm.14 Optical coherence tomography uses an infrared broadband light source that allows users to view skin architecture as deep as 1.5 to 2 mm with a resolution of 5 μm.15
When used synergistically, both devices can enhance the efficacy of nonablative laser treatment. With its increased depth and wider field of view, OCT is an optimal tool for repetitive evaluation of the same site over time and for following biopsy-confirmed tumors undergoing management.16 In addition to delineating tumor margins before treatment, imaging improves the detection of residual skin cancers, despite clearance on clinical and dermoscopic examination. Noninvasive imaging and nonsurgical management with laser therapy allow the physician to leave the skin intact and avoid scar tissue that might otherwise make it more difficult to detect and manage recurrence. The ability of OCT and RCM to monitor the efficacy of nonsurgical therapies for skin cancer has been demonstrated with imiquimod, photodynamic therapy, vismodegib, and ablative laser therapy.17-20
With limited data on nonablative laser management of BCC, several gaps in the literature exist. First, in previously published studies the number of treatments was either determined to be an arbitrary set number or based on clinical clearance, which has the potential to miss residual tumor. Second, many follow-ups were limited to shortly after the final treatment, which limits the accuracy of the clearance rate, given that inflammation and scars can hide residual tumor.21-23 Third, because many studies excised the treated area, long-term follow-up for recurrence was obscured. Last, only a few studies involved facial BCC, which is the most common and cosmetically concerning anatomic location.13
Our study attempted to address these gaps by evaluating the use of noninvasive imaging to guide management of primarily facial BCC. The objective was to perform a retrospective chart review on a subgroup of patients with BCC who were treated with combined nonablative PDL and fractional laser treatment with an extended follow-up period.