ESTRO 2023 - Abstract Book

S1269

Digital Posters

ESTRO 2023

study aimed to evaluate the effect of adjuvant radiotherapy on relapse and overall survival in patients with uterine sarcomas in our institution. Materials and Methods 41 patients who were diagnosed with uterine sarcoma and underwent hysterectomy were identified during the period from 2010 to 2021. After excluding patients with carcinosarcoma, 29 patients were included in the final analysis. Anatomopathological features, adjuvant treatments, dates and site of recurrence were collected. Univariate and multivariate analyses have been carried out. Results Mean age was 58.6 years. There were 17 LMS, 6 EES, 4 AS and 2 USS. FIGO stage at diagnosis was FIGO I, 18 patients; II, 3; III, 2 and IV, 6 patients. After surgery, 15 patients (51.7%) received adjuvant chemotherapy (CT) and 16 (55.17%) adjuvant radiotherapy (RT). 21 patients (72.4%) presented some type of recurrence with a mean time of onset of 24 months, of which three were loco regional, 17 distant (81%) and 1 patient both. The most frequent sites of distant metastases were pulmonary (58.8%) and carcinomatosis (29.4%). With a median follow-up of 43 months, 11 patients have died 10 cancer-specific (34.48%) with a mean of 36 months from the time of diagnosis. Currently 15 patients have stable disease and 3 patients are in progression. No statistically differences were found between histology, FIGO stage or adjuvant QT and the appearance of recurrence, time or location (loco regional or distant). Nor were differences found between these factors and death or time to death Statistically significant differences were found between the appearance of recurrence and RT (p = 0.003) with no differences between location or death. In the analysis by histology, differences were found in the LMS in favour of the administration of adjuvant RT both in the occurrence of recurrence (p=0.026) and death (p=0.036). These differences may be due to patient selection biases since it is those diagnosed in localized stages in which adjuvant RT were administered. Conclusion Postoperative radiotherapy in our series appear to reduce the chance of tumour recurrence with the potential to improve overall survival in selected histology. 1 Centro Hospitalar Universitário São João, Radioterapia, Porto e Região, Portugal, Portugal; 2 Instituto Portugues de Oncologia Lisboa, Radioterapia, Lisboa, Portugal Purpose or Objective Keloid scar is a benign dermal condition that occurs due to excessive fibroblast activation, leading to an abnormal accumulation of collagen. These scars can be asymptomatic or associated with discomfort, pruritus, and pain, which may have a negative impact on quality of life. Due to a high recurrence rate, combined treatments might be considered. Adjuvant radiotherapy (RT) has shown to be effective in reducing local recurrence. This study aims to evaluate scar-related results after adjuvant RT, assessed by patients and clinicians, as well as efficacy on recurrence. Materials and Methods Retrospective study including all patients with keloid scars undergoing surgical excision and adjuvant electron beam RT, from May 2016 to September 2022 at our hospital. The patient and observer scar assessment scale (POSAS) was used for all patients after RT, which assesses scar-related parameters (and overall score), scoring from 1 to 10. A RT dose of 18Gy/2fractions (9Gy/F), 7 days apart, was used, with 6MeV electrons and 3D conformal technique. All RT treatments began during the first 24h after surgery. Data was analyzed using IBM SPSS Statistics v28. Spearman correlation was used for POSAS scale parameters, and reliability was assessed using standardized Cronbach’s alpha and its variation in item-by-item removal. Kaplan-Meier’s method was used for survival analysis. A significance of .05 was considered. Results 32 patients and 36 keloid scars were evaluated, with a median follow-up of 3.5 years (interquartile range [IQR] of 8.25). Table 1 summarizes demographic, clinical and treatment data. No major adverse events were reported. Median for patient POSAS parameters varied between 1 and 3, with an overall score of 2 (IQR of 3, range 1-5). Significant correlations with overall score were observed for color ( ρ =.35, p=.042), stiffness ( ρ =.75, p<.001), thickness ( ρ =.74, p<.001) and irregularity ( ρ =.71, p<.001). Reliability for patient’s items was α =.796, with better contribution of stiffness, thickness and irregularity on item-by-item removal. Regarding observer parameters, medians varied between 1 and 2, with an overall score of 2 (IQR 1, range 1-5). All individual parameters showed significant correlations with overall score ( ρ >.55, p<.001). Reliability for these items was α =.898, with better contribution of thickness, relief, pliability and area on item-by-item removal. There was no significant correlation between patient and observer overall score ( ρ =.26, p=.14). Only one recurrence was observed, with a 1-year progression free survival of 93.8%. PO-1564 Using adjuvant radiotherapy for keloid scars: a patient and observer assessment study A. Alves 1 , C. Sá 2 , D. Saraiva 1 , P. Soares 1 , J. Casalta 1 , G. Pinto 1