Surgical treatment of basal cell carcinomas using standard postoperative histological assessment.

SUMMARY Surgical treatment of basal cell carcinomas using postoperative histological assessment is routinely practised in Australia. The efficacy of the procedure depends on key decisions made by the surgeon. The first is case selection that requires an understanding of the limitations of the procedure. The tumour border is then identified and a margin added. The margin selected should achieve the desired balance between incomplete excision rate and mean tissue sacrifice. There is an inverse relationship between these parameters; achieving a 5% incomplete excision rate requires a mean tissue sacrifice of over 4 mm. Factors affecting margin selection are discussed, unfortunately none allows a dramatic reduction in mean tissue sacrifice. The final decision involves interpreting and acting on the histological examination of the excised specimen. Tumour recurrence is rare (less than 2% at 5 years) if the tumour is clear of the surgical margin. The visualized histological margin required to ensure complete excision varies with histological technique and tumour properties. Routine reporting of histological margin in millimetres or horizontal sectioning is recommended. Tumour recurrence averages 38% when the histological margin is involved. The merits of careful clinical follow up of incompletely excised tumours or immediate re-excision are discussed.