In vivo imaging characterization of basal cell carcinoma cutaneous response to high dose ionizing radiation therapy: A prospective study of reflectance confocal microscopy, dermoscopy, and ultrasound.

ABSTRACT

BACKGROUND: Radiation therapy (RT) is a treatment option for selected skin cancers. The histologic effects of RT on normal skin or skin cancers are not well-characterized. Dermoscopy, high frequency ultrasonography (HFUS), and reflectance confocal microscopy (RCM) are non-invasive imaging modalities that may help characterize RT response. OBJECTIVES: To describe changes in the tumor and surrounding skin of basal cell carcinoma (BCC) patients treated with RT. METHODS: The study was conducted between 2014-2018. Patients with biopsy-proven BCCs were treated with 42 Gy in 6 fractions using a commercially available brachytherapy device. Dermoscopy, HFUS, RCM were performed before treatment, 6 weeks, 3 months and 12 months after RT. RESULTS: 137 imaging assessments (RCM + dermoscopy + HFUS) were performed in 12 patients. Presence of BCC-specific features were present in 81.8%, 91% and 17% of patients imaged with dermoscopy, RCM and HFUS at baseline, prior to treatment. After treatment, resolution of these features was noted in 33.4%, 91.7%, and 100% of patients imaged with the respective modalities. No recurrences were seen after 31.7 months mean follow-up. LIMITATIONS: Small sample size and no histopathological correlation. CONCLUSION: Dermoscopy and HFUS were not as reliable as RCM at characterizing BCCs RT response.