Clinical usefulness of high-frequency ultrasonography in the monitoring of basal cell carcinoma treatment effects

Introduction
To date, there has been no consensus either on the method, frequency or total duration of follow-up for patients that have developed a basal cell carcinoma (BCC).

Aim
To evaluate usefulness of high-frequency ultrasound in monitoring patients with BCC, particularly to detect residual disease or early recurrence.

Material and methods
Seventy-eight patients with suspicious lesions of BCC were enrolled in this study. Only patients for whom histologic evaluation confirmed diagnosis of BCC (70) continued the study. The dermatoscopic and ultrasonographic observation started before the treatment. Three control examinations were performed 4, 12 and 24 weeks after the treatment.

Results
A total of 70 basal cell carcinomas were examined in this study. The presence of cancer formation was observed in the margins of removed nodular BCC in 15% (6/40), in another 25% of cases the margin of surgical removal was narrow and was < 0.2 cm (10/40). For 4 of 6 (66%) lesions, in which histopathological examination demonstrated a positive margin, hypo or heteroechogenic, irregularly shaped focal lesions were found in the ultrasonographic examination just under the entrance echo on the first follow-up visit. In 2 other cases of positive margins of the removed BCC, no signs of residual disease were observed in ultrasonographic examination. For patients with a narrow margin of healthy tissues after surgical removal, hypo or heteroechogenic foci located directly under the entrance echo were also observed in the ultrasonographic examination 4 weeks after the surgery, suggesting the presence of cancer formation. Reduction in the suspected area and scar formation were observed on the subsequent visits. It was found that the characteristic feature of residual disease presence is an enlargement of the hypoechogenic area in subsequent ultrasonographic examinations.

Conclusions
The use of high-frequency ultrasonography in the monitoring of patients after surgery can accelerate and improve the diagnosis of residual disease.