FLASH Radiotherapy for Skin Cancer

Randomized Phase II Selection Trial of FLASH Versus Conventional Radiotherapy for Patients With Localized Cutaneous Squamous Cell Carcinoma or Basal Cell Carcinoma

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.

Inclusion Criteria:

• Signed study Informed Consent Form
• Karnofsky Performance Status (KPS) ≥ 60
• Age ≥ 60 years
• Patients with histologically proven cSCC or patients with BCC either histologically proven or proven by non-invasive imaging: either Optical Coherence Tomography (OCT), Line-field OCT (LC-OCT) or Reflectance Confocal Microscopy (RCM)
• Patients requiring radiotherapy treatment according to the dermato-oncology tumor board: patients who cannot undergo surgical procedure or patients who decline surgical resection, and/or anatomical locations where surgery can compromise function or cosmesis.
• T1-T2 N0 lesions with a small (T1; lesion ≤ 2cm in diameter) or large (T2; 2cm < lesion ≤ 4 cm) volume (TNM Classification of Malignant Tumours (TNM) Union for International Cancer Control (UICC), 8th Edition)
• Lesions should be at least 4 cm apart if treated with 2 different modalities (including surgical treatment of lesions). Lesions should not be located on the face, except on the forehead, above a line situated 1 cm above the eyebrows. Lesions located on the scalp can be treated.

Exclusion Criteria:

• Previous radiotherapy in the treated area
• Concomitant auto-immune disease with skin lesions
• Concomitant use of radio-sensitizer drug
• Cognitive disorders not compatible with the signature of informed consent or that may compromise compliance with the requirements of the study
• Current, recent (within 10 days prior to start of study treatment), or planned participation in an experimental drug study (before end of treatment (EOT) visit)
• Concomitant use of systemic chemotherapy for a cancer other than the skin cancer(s)