This is a single center randomized selected Phase II study of FLASH radiotherapy (RT) versus standard of care (SOC) radiotherapy in patients with localized Cutaneous Squamous Cell Carcinoma (cSCC) or Basal Cell Carcinoma (BCC). In summary, the aims of the study are to describe and compare the toxicity and efficacy of high dose rate radiotherapy (FLASH therapy) to SOC conventional radiotherapy (according to the standard guidelines per lesion size) through a randomized Phase II selection study in patients presenting localized cSCC or BCC requiring a radiotherapy treatment.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
60
For T1 (small) lesions: 22 Gy single dose FLASH RT; For T2 (large) lesions: 5 x 6 Gy fractionated dose FLASH RT
For T1 (small) lesions: 22 Gy single dose conventional RT; For T2 (large) lesions: 5 x 6 Gy fractionated dose conventional RT
Centre Hospitalier Universitaire Vaudois (CHUV)
Lausanne, Canton of Vaud, Switzerland
RECRUITINGFrequency of ≥ grade 3 skin toxicity adverse events (AEs) according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0
To evaluate the safety of FLASH radiotherapy measured by the collection of ≥ grade 3 skin toxicity AEs according to CTCAE version 5.0. The severity of a specific event is graded i.e. mild (grade 1), moderate (grade 2), severe (grade 3), life-threatening (grade 4), or death (grade 5) using the CTCAE Grading Table.
Time frame: up to 6 weeks after radiotherapy
Hierarchically tested efficacy measured by local control rate
At day 1, 21, 28, 42, and months 3, 6, and 12 post-treatment, the investigator will measure (with a caliper) the largest diameter of selected lesions for irradiation. Tumor response of each irradiated lesion will be assessed by the investigator as follow: * Complete Response: the irradiated lesion is no more visualized * Partial Response: the irradiated largest lesion dimension decreased by 30% at least from baseline (day 1) * Progressive Disease: the irradiated largest lesion dimension increased by 20% at least from baseline (day 1) * Stable Disease: no Complete Response, no Partial Response, no Progressive Disease
Time frame: From Day 1 up to 12 months post-treatment
Frequency of acute side effects observed "in radiation field"
Time frame: up to 3 months after radiotherapy
Frequency of late side effects observed "in radiation field"
Time frame: from ≥ 3 months after radiotherapy until 12 months post-treatment start
Evaluation of tumor response
Blinded Imaging Central Review (BICR) of photographs will evaluate tumor response by grading the size of the residual tumor in comparison to the size of the tumor on the day of irradiation (in percentage). 0% means no residual tumor and treatment success, 100% or more indicate a total lack of tumor response. A baseline photograph will be taken the day of the treatment (day 1) in a pre-therapeutic setting with skin delineation of the lesion. Then photos will be repeated at day 21 (+/-2d), day 28 (+/-2d), day 42 (+/-3d) after treatment, then at 3 (+/-7d), 6 (+/-14d), 12 (+/-14d) months after treatment, and at progression.
Time frame: From Day 1 up to 12 months post-treatment
Evaluation of "in radiation field" normal tissues reaction around the treated tumors
Blinded Imaging Central Review (BICR) of photographs will evaluate "in radiation field" normal tissues reaction around the treated tumors by grading radiation induced skin reactions, grade 1-5, using the CTCAE scale. A baseline photograph will be taken the day of the treatment (day 1) in a pre-therapeutic setting with skin delineation of the lesion. Then photos will be repeated at day 21 (+/-2d), day 28 (+/-2d), day 42 (+/-3d) after treatment, then at 3 (+/-7d), 6 (+/-14d), 12 (+/-14d) months after treatment, and at progression.
Time frame: From Day 1 up to 12 months post-treatment
Epidermis thickness measured by Optical coherence tomography (OCT)
Epidermis thickness in micrometer will be measured by OCT and compared between irradiated skin and normal non-irradiated skin
Time frame: at baseline, at 4 weeks, at 6 months, and at 12 months post-treatment
Epidermis roughness measured by OCT
Epidermis roughness in micrometer will be measured by OCT and compared between irradiated skin and normal non-irradiated skin
Time frame: at baseline, at 4 weeks, at 6 months, and at 12 months post-treatment
Plexus depth measured by OCT
Plexus depth in micrometer will be measured by OCT and compared between irradiated skin and normal non-irradiated skin
Time frame: at baseline, at 4 weeks, at 6 months, and at 12 months post-treatment
Vessel density measured by OCT
Vessel density, expressed as percent of the surface covered by the vessels in the examined area, will be measured by OCT and compared between irradiated skin and normal non-irradiated skin
Time frame: at baseline, at 4 weeks, at 6 months, and at 12 months post-treatment
Size of vessels measured by OCT
Mean size (in micrometer) of all vessels in the examined area will be measured by OCT and compared between irradiated skin and normal non-irradiated skin
Time frame: at baseline, at 4 weeks, at 6 months, and at 12 months post-treatment
Number of hairs counted by OCT
Number of hairs in the examined area will be counted by OCT and compared between irradiated skin and normal non-irradiated skin
Time frame: at baseline, at 4 weeks, at 6 months, and at 12 months post-treatment
Size of hairs measured by OCT
Mean size (in micrometer) of all hairs in the examined area will be measured by OCT and compared between irradiated skin and normal non-irradiated skin
Time frame: at baseline, at 4 weeks, at 6 months, and at 12 months post-treatment
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