Radiotherapy by Sonic Hedgehog Pathway Inhibitors in Basal Cell Carcinoma

Study Overview
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Brief Summary
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Locally advanced basal cell carcinoma (BCC) are large BCCs or BCCs located in areas subject to functional and aesthetic risk following surgery or radiotherapy. In these particular situations, surgery and radiotherapy are sometimes not appropriate, and Sonic Hedgehog inhibitors (SHHi) (Vismodegib and Sonidegib) can be proposed. SHHi are effective treatments in laBCC but most CR patients discontinue treatment because of tolerability. Approximately 65% of the population experience a relapse after discontinuation. A few cases of patients treated concomitantly by radiotherapy and vismodegib have been reported in the literature, suggesting that combining vismodegib and concomitant radiotherapy results in an improved overall response compared to a single modality treatment. There is no study evaluating a consolidation radiotherapy after complete response to SHHi. We carry out a prospective multicenter study in order to evaluate consolidation radiotherapy in patients with laBCC after achieving complete response with SHHi, with the hypothesis of reducing recurrence after discontinuation of SHHi.

Official Title
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Evaluation of Radiotherapy After Complete Response to Sonic Hedgehog Pathway Inhibitors in Patients With Locally Advanced Basal Cell Carcinoma: a Prospective Multicenter Study

Conditions
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Basal Cell Carcinoma, Radiotherapy; Complications

Intervention / Treatment
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* Radiation: Radiotherapy
* Other: Observation
* Drug: Vismodegib


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient over 18 years Locally advanced non-recurrent BCC in complete response after first course of SHHi Complete response has to be confirmed histologically Available photography or CT scan before SHHi treatment allowing delineation of the initial tumor Exclusion Criteria: Patients with distant metastasis Patients with Gorlin's syndrome Prior radiotherapy to the region of the studied cancer that would result in overlap of radiation therapy fields Pregnant women Life expectancy less than 1 year Inability to receive informed consent Inability to participate in the entire study Lack of social security coverage Refusal to sign consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: SHHI then follow-up<br> | Radiation: Radiotherapy<br>* Irradiation of the tumoral bed.<br>Other: Observation<br>* Patients will be followed up in consultation every 3 months.<br>|
| Experimental: SHHI then radiotherapy<br> | Radiation: Radiotherapy<br>* Irradiation of the tumoral bed.<br>Drug: Vismodegib<br>* Sonic Hedgehog inhibitors (SHHi) = Vismodegib et Sonidegib,<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Occurrence of a local relapse at 2 years in both groups. |  | At 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Occurrence of local relapse at 1 and 3 years. |  | at 1 year and at 3 years | 
| Occurrence of adverse effects in the radiotherapy group. |  | at 1 year, at 2 years and at 3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Locally advanced basal cell carcinoma, Sonic Hedgehog inhibitors, Consideration radiotherapy