BackgroundBasal cell carcinoma (BCC) is the most common cancer in the Caucasian population.
It has a multifactorial pathogenesis, in which constitutive activation of the Sonic
Hedgehog signalling (SHH) pathway (via mutations in PTCH1 or SMO genes) represents
by far the most common genetic aberration. The introduction of vismodegib and sonidegib,
two SHH pathway inhibitors, changed the therapeutic approach of locally advanced and
metastatic BCCs. EADO's (European Association of Dermato-Oncology) new staging system
refers to these as 'difficult-to-treat' BCCs.ObjectiveThe aim was to evaluate sonidegib's
effectiveness in patients affected by difficult-to-treat BCCs by using non-invasive
diagnostic techniques.MethodsWe retrospectively evaluated 14 patients (4 females,
10 males; mean age 77 +/- 11 years) affected by difficult-to-treat BCCs treated with
oral sonidegib 200 mg/day that were followed with total body videodermoscopy (V-Track,
Vidix 4.0) and dynamic optical coherence tomography (D-OCT, VivoSight Dx) since May
2022. Considering the risk of rhabdomyolysis routine blood tests, especially for creatine
kinase concentrations, were performed. All treated patients were inserted in the BasoCare
database, which aims to offer support to patients taking sonidegib. Complete and partial
responses were evaluated by the overall reduction of the number of lesions and their
individual sizes. Safety was evaluated by assessing the occurrence and severity of
adverse reactions.ResultsEighty per cent achieved complete clearance and 75% reduction
of diameter. D-OCT scans performed at every follow-up showed concordance with clinical
appearance and demonstrated reduction of hyporeflective structures, that is, islets
of tumour cells and overall improvement of morphology.ConclusionSonidegib can be considered
an effective treatment option in cases where surgery or radiotherapy would be unfeasible
or has previously failed, although pigmented lesions did not show complete clearance,
suggesting that there are factors other than the SHH pathway involved in tumour growth.
Videodermoscopy and D-OCT were useful in the quick and seamless follow-up of lesions
and added valuable information in assessing efficacy.
