OPTICAL COHERENCE TOMOGRAPHY EVALUATION IN LOCALLY ADVANCED BASAL CELL CARCINOMA DURING SYSTEMIC TREATMENT

Background: Basal cell carcinoma (BCC) is the most common cancer in the Caucasian population, and in Italy its incidence is around 100 cases per 100,000 population. It has a multifactorial pathogenesis, and the most important environmental risk factor is ultraviolet radiation (UV) while constitutive activation of Sonic Hedgehog signaling pathway (via mutations in PTCH1 or SMO genes) instead, is by far the most common genetic aberration associated with these tumors. Basal cell carcinoma often has an indolent biological behavior: it has a predominantly local malignancy, rarely metastasizing (0.05-0.1% of cases). In low-risk or superficial BCC, topical or locally destructive therapy is possible, although surgery remains the treatment of choice. Observation: Locally advanced or metastatic basal cell tumors still represent a therapeutic challenge today. Several therapies are currently available in these clinical setting such as radiotherapy and targeted treatments directed against the Hedgehog pathway. With the introduction of Vismodegib and Sonidegib, two hedgehog pathway inhibitors, a response rate of 67% was observed in locally advanced disease and 38% in metastatic disease. We evaluated Sonidegib effectiveness in patients affected by multiple or locally advanced basal cell carcinoma by using non-invasive diagnostic techniques such as videodermoscopy and optical coherence tomography (OCT). Key message: Systemic agent can represent an useful tool in the management of difficult patients and OCT an excellent and easy to use non-invasive technique for the evaluation of non-melanoma skin cancers.