ESTRO 2025 - Abstract Book

S1708

Clinical - Sarcoma & skin cancer & malignant melanoma

ESTRO 2025

Keywords: melanoma, oligoprogression 3062

Digital Poster Definitive Tomotherapy-based radiotherapy facial lentigo maligna. The experience of Centro di Riferimento Oncologico di Aviano CRO-IRCCS Giuseppe Fanetti 1 , Paola Corsetti 2 , Giuseppe Anastasio 3 , Valentina Lupato 4 , Paola Pase 1 , Lisa Andreon 1 , Federica Bertini 1 , Manuele Roghi 1 , Andrea Sighinolfi 1 , Jerry Polesel 5 , Paola Chiovati 3 , Vittorio Giacomarra 4 , Maurizio Mascarin 1 , Maria Antonietta Pizzichetta 2 1 Division of Radiation Oncology, Centro di Riferimento Oncologico di Aviano CRO IRCCS, Aviano, Italy. 2 Division of Dermato-Oncology, Centro di Riferimento Oncologico di Aviano CRO IRCCS, Aviano, Italy. 3 Division of Medical Physics, Centro di Riferimento Oncologico di Aviano CRO IRCCS, Aviano, Italy. 4 Division of Otolaryngology, General Hospital "S. Maria Degli Angeli", Pordenone, Italy. 5 Unit of Cancer Epidemiology, Centro di Riferimento Oncologico di Aviano CRO IRCCS, Aviano, Italy Purpose/Objective: Lentigo maligna (LM) is in situ melanoma arising in sun-exposed areas. Surgery represents the treatment of choice. Radiotherapy can be used as treatment option when surgery is infeasible. Tomotherapy allows the treatment of skin areas with curvature and maximize skin coverage. Our aim is to report results of LM treatment with definitive Tomotherapy. Material/Methods: A retrospective report of patients treated at our institution in 2022 was performed. Dermoscopy and reflectance confocal-microscopy helped in biopsy site selection for histopathological diagnosis. Radiotherapy was offered when surgery was contraindicated or according to patient preference. Before the CT scan simulation, the lesion was delineated by the dermato-oncologist with dermoscopy and reflectance-confocal-microscopy to define subclinical LM margins. A metallic landmark was posed on the delineation area and a thermoplastic mask molded for radiotherapy simulation. The area within the metallic landmark defined the Gross Tumor Volume (GTV) and the Clinical Target Volume (CTV) was defined by adding 5 mm to the GTV. Tomotherapy prescription dose was 50 Gy in 20 daily fractions, five fractions per week.