No clinical benefit of preoperative fluorescence diagnosis of basal cell carcinoma localized in the H-zone of the face

Abstract

Basal cell carcinoma (BCC) is the most common malignant skin carcinoma. Fluorescence diagnosis (FD) has been suggested as a promising method for noninvasive detection of subclinical tumour cell dissemination in BCC. In this prospective study, we evaluated the clinical performance of a preoperative definition of the lateral borders of BCC by FD in comparison with its definition by purely clinical diagnosis (CD). The fluorescence intensity on the skin was recorded using a digital light-emitting diode-based fluorescence imaging system. Twenty-six patients with BCC (22 with nodular subtype) of the H-zone were included. The tumour area was determined 3 h after application of methyl aminolaevulinate by inspection and photographic documentation (CD) and FD. Subsequently, BCCs were excised according to the complete area defined by CD and FD with a security margin of 3 mm; surgical specimens were sectioned horizontally and subjected to meticulous histological mapping. The tumour areas as determined by FD, CD and histology were superimposed to map the entire lateral tumour margin. The tumour area could be visualized by FD in 24 of 26 patients. The mean tumour area as determined by FD was significantly smaller than the tumour area as determined by CD [80 mm(2) , 95% confidence interval (CI) 50-110 mm(2) vs. 101 mm(2) , 95% CI 76-125 mm(2) ; P < 0·012]. The superimposition of FD and histology showed in 10 of 26 patients a complete detection of the tumour margin by FD; thus sensitivity of FD was calculated as 38·5%. In only three of 26 patients FD revealed a tumour extent greater than determined by CD. Specificity of FD was calculated as 88·4%. On aggregate, this study suggests that preoperative FD of nodular BCC localized in the H-zone offers no additional benefit to define subclinical tumour infiltration compared with CD alone.