The aim of this study was to identify psycho-social factors associated with diagnostic delay in advanced basal cell carcinomas. Thus, the objective is to develop recommendations to better identify CBCa populations at risk, improve earlier their diagnosis and thus their care with an adequate and targeted information.

Skin cancers incidence is constantly increasing as a result of ageing of the population, and is then a critical issue of concern. Among skin cancers, basal cell carcinoma is the most common. Its treatment is mainly based on surgery that has to be done early. Indeed, CBC can lead to progressive destruction of tissues and significant morbidity in advanced stages. In these advanced stages (CBCa), they are no longer accessible to surgery or radiation therapy. The recently developed targeted therapies represent a significant therapeutic progress. To date, there are few data -none in France- concerning the cause of diagnostic delay .

Thus, the main goal of this study will be to evidence the brakes and facilitators who chair the decision-making to consult in patients with a CBCa, by investigating:

• the perception of the target subjects (patients);
• the perception of the healthcare team; We will also conduct a critical meta-synthesis (qualitative meta-analysis) of the literature concerning the diagnostic delay and decision-making in onco-dermatology.

It is a prospective non-Interventional exploratory qualitative study without direct individual benefit

Inclusion Criteria:

• Patients over 18 years of age with a CBCa supported for less than 12 months in the onco-Dermatology unit of the CHU de Bordeaux.
• Are defined as locally advanced,tumors with major invasion of adjacent structures, that are not accessible for surgical resection or radiotherapy, .
• Patients will sign a consent after reading the fact sheet explaining the objectives of the study.

Exclusion Criteria:

• subjects with severe dementia (mini mental state less than 10)
• An anonymized list of non-included according to this criterion will be carried out in order to quantify the number of advanced CBC with severe dementia and also the number of refusals.