ESTRO 2023 - Abstract Book

S1275

Digital Posters

ESTRO 2023

1 University College Cork, Medical Imaging and Radiation Therapy, Co. Cork, Ireland; 2 Cork University Hospital, Radiation Oncology, Co. Cork, Ireland Purpose or Objective Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children requiring multimodality treatment with chemotherapy, surgery, and radiation therapy (RT) for curative intent. Proton beam therapy (PBT) presents a method of local therapy in paediatric RMS patients that has been associated with increased sparing of healthy tissue but with similar disease control. Despite this, the level of high-quality randomised evidence in the literature is lacking, especially in the setting of localised RMS disease. For this reason, a systematic review of the literature on PBT for paediatric RMS patients was conducted to determine its clinical efficacy and identify toxicities. Materials and Methods A review protocol was developed as per PROSPERO guidelines. A search of five databases (PUBMED/MEDLINE, EMBASE, CINAHL, Scopus and Cochrane Library) was carried out according to PRISMA guidelines between January 2010 – December 2021. Eligible studies included paediatric and adolescent patients ( ≤ 18 years) who received proton beam RT for localised RMS or metastatic disease and in whom clinical outcomes of local control (LC), overall survival (OS) or toxicity as graded by the common terminology criteria for adverse events (CTCAE) were reported. Results 198 publications were eligible for title and abstract screening by two reviewers with five studies eligible for inclusion (90 patients). All five studies were case series, four retrospective, and one prospective. The majority of patients had embryonal subtype, the median dose delivered was 47.7GyE (36 – 50/4GyE) and the median follow-up was 37 (18 – 60) months. Local control (LC) and Overall survival (OS) were reported in three studies. 2-year LC and OS rates were reported as 88% and 89%, respectively in one publication, and 5-year LC and OS rates of 83-97% and 83-100%, respectively in 2 publications. Acute (N=2) and late (N=5) CTCAE were reported, with no grade 4 or higher RT-related toxicities. Cataracts were the most commonly reported late toxicity. Conclusion PBT appears to be a safe and effective method of local therapy as part of the multimodality treatment of paediatric RMS patients with localised disease. However, a better quality of evidence is required. 1 University Medical Center Utrecht, Radiation Oncology, Utrecht, The Netherlands; 2 Radboud University Medical Center, Psychiatry, Nijmegen, The Netherlands; 3 University Medical Center Utrecht Brain Center, Psychiatry, Utrecht, The Netherlands Purpose or Objective The effect of a psychiatric disorder (PD) on the choice of radiotherapy regimens and subsequent cancer control outcomes is largely unknown. In this study, we evaluated differences in radiotherapy regimens and overall survival (OS) between cancer patients with a PD in comparison with a control population of patients without a PD. Materials and Methods Referred patients with a PD (i.e. schizophrenia spectrum disorder, bipolar disorder, and borderline personality disorder) were included through a text-based search of the electronic patient database of all the patients that received radiotherapy between 2015-2019 at a single centre. Each patient was matched to a patient without a PD. Matching was based on cancer type, staging, performance score (WHO/KPS), non-radiotherapeutic cancer treatment, gender and age. Outcomes were the amount of fractions received, total dose, and OS. Results 88 patients with PD were identified; 44 patients with schizophrenia spectrum disorder, 34 with bipolar disorder, and 10 with borderline personality disorder. Matched patients without a PD showed similar baseline characteristics. No statistically significant difference was observed regarding the number of fractions with a median of 16 (interquartile range [IQR] 3-23) versus 16 (IQR 3-25), respectively (p=0.47). Additionally, no difference in total dose was found. Kaplan Meier curves showed statistically significant differences in OS between the patients with a PD versus those without a PD, with 3-year OS rates of 47% versus 61%, respectively (hazard ratio [HR] 1.57, 95%-CI 1.05-2.35, p=0.03). Conclusion Cancer patients referred for radiotherapy with schizophrenia spectrum disorder, bipolar disorder, or borderline personality disorder receive similar radiotherapy schedules for a variety of tumour types but attain worse survival. Poster (Digital): Mixed sites/palliation PO-1571 Psychiatric comorbidity impact on radiotherapy and overall survival: a matched pair analysis. M. Peters 1 , H. Boersma 1 , P. S.N. van Rossum 1 , J. van Oort 2 , W. Cahn 3 , J. J.C. Verhoeff 1

PO-1572 Recognition and treatment recommendations of oligometastasis in multidisciplinary tumor boards

S.M. Christ 1 , P. Heesen 2 , U.J. Muehlematter 3 , K. Pohl 2 , G.W. Thiel 2 , J. Willmann 1 , M. Ahmadsei 1 , T.E. Kroese 1 , M. Mayinger 1 , P. Balermpas 1 , A. Wicki 4 , N. Andratschke 1 , M. Huellner 3 , M. Guckenberger 1