Background: To determine the 5 year outcome of periocular basal cell carcinoma (BCC) managed by Mohs surgery using formalin-fixed, paraffin-embedded sections (Slow Mohs).
Methods: This was a prospective, non-comparative, interventional case series of all patients with periocular BCC treated by Slow Mohs in Newcastle between 1985 and 1999. Data collected included demographic information, indication for Slow Mohs, tumour site, histology, recurrence rates after 5 years and cosmetic outcome.
Results: Of 287 BCC in 278 patients, 5-year follow-up was available on 182 (63%). Recurrence following Slow Mohs occurred in 1 patient: 0.34% of total and 0.54% of those with 5-year follow-up. The main indication for Slow Mohs was most frequently due to the tumour site. Cosmetic outcome was deemed excellent in 56%, good in 18%, adequate in 8%, unknown in 14% and revision advised in only 4%.
Conclusion: The low 5 year recurrence rate (0.54%) reported in this prospective series confirms the importance of margin-controlled removal of recurrent, poorly defined or critically sited BCC and illustrates that Slow Mohs is equivalent to standard Mohs. While delayed closure does not appear to compromise cosmetic outcome, this technique offers a histologically superior and cheaper alternative to frozen section Mohs surgery.