ESTRO 2021 Abstract Book

S1256

ESTRO 2021

Via the satisfaction questionnaire, participants scored the workshops usefulness (4.17/5), programme (4.25/5), fulfillment of educational goals (4.25/5), the information presented as evidence based (4.33/5), implementation in the participant’s practice (4.58/5), the expert’s presentation (4.17/5). One participant (1/21; 5%), suggested that less time should have been dedicated to autosegmentation.

Conclusion Overall, participants were very satisfied with the training provided by this workshop, including the autosegmentation segment. Further incorporation of autosegmentation in delineation workshops with a more specific evaluation of the participants’ perception of this training is warranted to better assess its impact. PO-1533 Radiotherapy for recurrent keloids: a retrospective review in our centre. Is it worth to treat? M. Colomer 1 , E. Mur 2 , M. Galdeano 2 , A. López 1 , D. Amat 1 , G. Frontera 1 , U. Gallardo 1 , A. Peralta 1 , M. Parcerisa 1 , R. Pujol 1 , D. Navarro 1 , E. Ambroa 1 , J. García-Miguel 1 , T. Valdivielso 1 , M. Lizondo 1 , Á. Infestas 1 , T. Ramírez 1 1 Consorci Sanitari de Terrassa, Medical Physics Unit, Terrassa, Spain; 2 Consorci Sanitari de Terrassa, Radiation Oncology Department, Terrassa, Spain Purpose or Objective Radiation therapy for benign diseases has been well established since German consensus in 2000 however it remains controversial. Keloids are abnormal fibrous growth in scars after surgery, piercing or other types of skin injuries, with high level of recurrence. The standard treatment of these recurrences is surgery followed by radiotherapy beginning in the first 24 hours. We aimed to assess toxicity and recurrence rate occurred in our institution to decide continuing with this treatment or not. Materials and Methods We retrospectively analysed all patients with recurrent keloids who underwent radiotherapy after surgery in our centre from 2013 to 2021. All patients were treated with electron beam radiotherapy within 24 hours after surgery. 22 keloids in 19 patients were irradiated: 19 using 6 MeV, 2 using 9 MeV and 1 with 12 MeV. Bolus was used to ensure maximum dose to scar bed. 15 Gy in 3 fractions were delivered to the excision scar plus a safety margin. 14 patients (73.7%) had had previous treatments like surgery alone, surgery and corticosteroid injections or cryotherapy. Median follow-up was 21.2 months (mean: 22.3, range: 0.1–78.7). One patient had no follow up because he