Three‐dimensional histology vs. serial section histology in the treatment of primary basal cell carcinoma: a randomized, prospective, blinded study of 569 tumours

Abstract Background For basal cell carcinoma (BCC), only few controlled data have been published so far, which directly compare micrographically controlled surgery with conventional serial section histology. In addition to Mohs surgery, which uses cryostat sections, also three‐dimensional histology (3D‐histology), based on paraffin sections, is available to ensure complete control of the margins and basic sections. Objectives To investigate the rate of local recurrence (LR) as well as the number of required re‐excisions for basal cell carcinomas with serial section histology vs. 3D‐histology. Methods We compared serial sections histology with 3D‐histology in a prospective, randomized, controlled blinded trial and analysed 569 BCC of all subtypes up to 30 mm diameter, 287 BCC in the 3D group and 282 BCC in the serial section group. Excisions were performed with adapted primary resection margin according to location and size of the tumour. Surgeons were blinded at the time of surgery as they did not know which histological method will be used. Both methods used paraffin sections. Results Both groups did not differ regarding patients age, tumour location, tumour diameter, tumour subtypes or primary resection margins. In the serial section group, re‐excisions were required in 21%; 24 tumours (8.4%) recurred after a median of 2.2 years. In the 3D‐histology group, re‐excisions were required in 39%; 10 tumours recurred (3.5%) after a median of 2.8 years. The recurrence rates differed significantly between both groups. Mean follow‐up was 4.5 years. Conclusions 3D‐histology is a useful technique to detect tumour outgrowths at the excision margins, but required a high rate of re‐excisions. 3D‐histology was associated with a significantly lower LR rate than serial section histology.