ESTRO 2025 - Abstract Book

S313

Brachytherapy – Head & neck, skin, eye

ESTRO 2025

4120

Digital Poster Assessing the efficacy and safety of plesiotherapy for non-melanomatous skin cancer: an opportunity of local control on elder patients. Julen Azcona Martin 1 , Marta Camacho Manzanares 1 , Raúl Hernánz De Lucas 1 , Marina Alarza Cano 1 , Ignacio María Gómez Paloma 1 , Adrian Durango 1 , Jose Antonio Domínguez Rullán 1 , Teresa Muñoz Miguelañez 1 , Rafael Colmenares Fernández 2 , Belén Capuz Suarez 2 , Isabel Alvira 1 , María Dolores Espinosa 1 , Margarita Martín 1 , Carlos Rodríguez Manzaneque 2 1 Radiation Oncology, Ramón y Cajal University Hospital, Madrid, Spain. 2 Radiophysics, Ramón y Cajal University Hospital, Madrid, Spain Purpose/Objective: With this project we aim to showcase our experience in the use of plesiotherapy for both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) of the skin, focusing on the clinical outcomes and safety profile. Non melanoma skin cancer can comprehend up to 3.000.000 new cases/year and radiotherapy stands up as an option for unresectable patients. The shape adapting thermoplastic moulds along the plastic catheters allow the administration of high-dose rate brachytherapy in a very precise and bounded way. Material/Methods: Between February 2016 and June 2023 we treated up to 128 patients suffering non-melanomatous skin cancer, plesiotherapy was selected for 49 of those cases (38%). Amongst this group treated with plesiotherapy 26 were men 23 women, the median age was 87 years old (59-103), and they presented ECOG 1 in 29,5% , ECOG 2 in 52% and ECOG 3 in 18.5%. In this cohort treated with plesiotherapy 51% were SCC and 49% were BCC; and the lesions were mainly set in frontal and nasal regions (equally 32,65% each). The most commonly used factioning schemes were 40Gy/45Gy/48Gy/54Gy in 8-12 fractions of 400-450 cGy each delivered on alternate days. All the patients undergoing plesiotherapy had a thermoplastic moulds done and a non contrasted CT performed for planning. Results: The median follow up time was 20,1 moths, ranging from 1,6 to 79,9 months. During this period we notified that 43 patients (87,7%) remained free of local disease on their last follow up with physical examination, 5 patients progressed (10%) and just one patient died due to complications of the cancer progression systemically. As for the tolerance, in the 87% of the cases acute cutaneous toxicity appeared (mild G1-G2 epithelitis), with only a 6% of G3 epithelitis. All of them answered to local treatment evolving to 30% G1 chronic toxicity consisting mainly in mild hypopigmentation. There was only a single case of severe toxicity on a patient that presented a necrotic spot on the covering flap. Conclusion: Plesiotherapy has shown to be a feasible treatment for patients with non-melanomatous skin cancer in both post surgical and inoperable patients. In this series we report a great local control in other way untreatable elder patients, with acceptable toxicity rates that consist mainly in mild acute and transient epithelitis.

Keywords: Plesiotherapy, non-melanomatous, elder