Neoadjuvant vismodegib in the management of locally advanced periocular basal cell carcinoma

Background/objectives: Vismodegib, a hedgehog pathway inhibitor, has been used in the management of locally advanced basal cell carcinoma (BCC) not suitable for surgery or radiation therapy. We report our experience using neoadjuvant vismodegib for locally advanced periocular BCC, followed by surgical excision. Our aim was to assess the effect on the extent of surgical excision and histological response.

Subjects/methods: A retrospective case series of patients treated with neoadjuvant vismodegib, for the management of locally advanced periocular BCC prior to surgical excision, with intraoperative margin control. Patients were treated until a maximum clinical response was seen. The difference between the estimated surgical margins prior to vismodegib and the eventual margins used was compared. Fine (1 mm) vertical sections through the excised tumour were performed to assess the histological response and look for a multifocal tumour.

Results: Eight Caucasian patients had neoadjuvant treatment with vismodegib for a median duration of 6 months. Some clinical response was seen in all cases but was only partial in 6/8 patients. Histological evaluation of the excised specimen showed residual BCC in 6/8 cases and thus 2/8 showed complete histological regression. Two cases showed squamous differentiation. Side effects occurred in 7/8 patients all which resolved on cessation of therapy. The mean follow-up was 13.4 ± 5.2 months.

Conclusions: Neoadjuvant treatment of periocular BCC showed a mixed clinical and histological response. Final surgical excision achieved clear margins in all patients with no recurrence at 13 months and a reduction in predicted defect size, but possible squamous differentiation in two cases.