High-resolution Ultrasound During Photodynamic Therapy of Basal Cell Skin Cancer of the Head and Neck

Aim . To determine the possibilities of high-resolution ultrasound examination of the skin at planning of photodynamic therapy and in the early post-therapeutic period. Materials and Methods . 128 patients referred for photodynamic therapy (PDT) of basal cell skin cancer of the head and neck region were examined. The PDT was preceded by two diagnostic techniques: fluorescence diagnostics (FD) and high-resolution ultrasonography. The latter was performed before and within 24–72 h after PDT on an expert class device Philips Epic 7 (USA), high-frequency linear transducer eL18-4 using MicroFlow Imaging (MFI) technology. Results . Horizontal and vertical dimensions and tumor microvascularization were assessed by ultrasound. Depending on thickness and vascularization, all tumors were divided into three groups: with peripheral vascular pattern (Me 1.6 mm), with peripheral and central vascular pattern (Me 2.4 mm), and with no vascular pattern (Me 1.3 mm). Significant statistical differences (p < 0.001) were found that were dependent on tumor thickness. When comparing the horizontal dimensions obtained by ultrasound and fluorescence diagnostic methods, a moderately close direct relationship was found, which was attributed to the difference in techniques. When the primary horizontal dimensions at ultrasonography (extent) increased by 1 mm, an increase in dimensions at FD of 0.413 mm was to be expected. The resulting model explained 15.9 % of the observed size variance in FD. Based on the results of tumor thickness data in ultrasonography and horizontal margins in FD, the parameters of PDT were determined. Evaluation of microvascularization of the pathological focus in the period 24–72 h after PDT predicted the outcome of PDT. The vascular pattern in the tumor was absent in 90.5 % of cases (excluding masses with uninformative vascular pattern at the primary examination), in 7.6 % of cases peripheral vascular pattern was visualized, most likely it was connected with the signs of active inflammation of the surrounding tissues. In 1.9 % of cases intratumoral vascularization remained, which required a repeated PDT session. Conclusions . Ultrasound skin examination in combination with FD allows to optimize PDT and to estimate the therapeutic effect of the procedure in the early post-therapeutic period.