ESTRO 2020 Abstract Book

S215 ESTRO 2020

advanced cervix cancer (LACC). The aim of this prospective mono-institutional study was to correlate patient characteristics and dosimetric parameters in a homogeneous patient cohort with LACC undergoing RCT as part of definitive treatment. Various endpoints of early patient reported outcome (PRO) and physician reported morbidity (PhyRO) were considered and analyzed via multiple questionnaires for patients treated with different EBRT techniques. Material and Methods Our study population consisted of 48 patients diagnosed with LACC, FIGO stage Ib-IVb, who were all treated with RCT and followed by image-guided adaptive brachytherapy (IGABT). EBRT was administered as 3DCRT, VMAT or Adaptive EBRT (ART). Acute toxicity was evaluated at baseline, weekly during and at weeks 1, 6 and 12 after commencing the treatment. Following questionnaires were used: CTCAE 4.03 (PhyRO) with some specific items used in institutional practice (daily micturition, stool consistency, stool urgency), QLQ-C30 and EORTC QLQ- CX24 (PRO). Target and organ contouring and treatment planning was based on EMBRACE I or EMBRACE II guidelines. Correlation between acute toxicity, classified as general, gastrointestinal (GI) or genitourinary (GU), and their corresponding EBRT DVHs was evaluated by multiple logistic binomial regression after feature selection by 3DCRT was applied in 3 patients, VMAT with fixed margins in 31 and ART based on plan of the day approach in 14 patients. The treated volumes varied for the different EBRT techniques, decreasing from ~2500 cm³ for 3DCRT to ~2000 cm³ for EMBRACE I VMAT treatment further to ~1800 cm³ for EMBRACE II VMAT cohorts. Various GU, GI and general symptoms were reported. In general, a worsening of symptoms during the first 5 weeks of treatment and recovery afterwards was observed, irrespective of EBRT technique. No G4-G5 toxicity was reported. The incidence of symptoms correlating with dose-volume parameters was: dysuria in 22 (46%), urinary incontinence in 14 (29%), stool urgency in 12 (25%), rectal bleeding in 4 (8%) and rectal incontinence in 11 (23%) patients. Diarrhea only correlated when it was persistently present after treatment. Weight loss and back pain were reported by the majority of patients. Some patient specific parameters also correlated with side effects. The significant parameters of the multivariate logistic regression are described in Table 1. LASSO. Results

volume parameters correlated with stool urgency, rectal and urinary incontinence and can be used to minimize early morbidity. PH-0404 Risk factors for late diarrhoea after radio(chemo)therapy in cervical cancer: EMBRACE I results N.B.K. Jensen 1 , R. Pötter 2 , L.U. Fokdal 1 , C. Chargari 3 , J.C. Lindegaard 1 , M. Schmid 2 , A. Sturdza 2 , U. Mahantshetty 4 , I.M. Jürgenliemk-Schulz 5 , P. Hoskin 6 , B. Segedin 7 , B. Rai 8 , K. Bruheim 9 , E. Wiebe 10 , E. Van der Steen-Banasik 11 , R. Cooper 12 , E. Van Limbergen 13 , M. Sundset 14 , B.R. Pieters 15 , R. Nout 16 , C. Kirisits 2 , K. Kirchheiner 2 , K. Tanderup 1 1 Aarhus University Hospital, Department of Oncology, Aarhus, Denmark ; 2 Medical University/General Hospital of Vienna, Department of Radiation Oncology- Comprehensive Cancer Center, Vienna, Austria ; 3 Gustave-Roussy, Department of Radiotherapy, Villejuif, France ; 4 Tata Memorial Hospital, Department of Radiation Oncology, Mumbai, India ; 5 University Medical Centre Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands ; 6 Mount Vernon Hospital, Mount Vernon Cancer Centre, Northwood, United Kingdom ; 7 Institute of Oncology Ljubljana, Department of Radiotherapy, Ljubljana, Slovenia ; 8 Postgraduate Institute of Medical Education and Research, Department of Radiotherapy and Oncology, Chandigarh, India ; 9 The Radium Hospital- Oslo University Hospital, Department of Oncology, Oslo, Norway ; 10 Cross Cancer Institute and University of Alberta, Department of Oncology, Edmonton, Canada ; 11 Radiotherapiegroep Arnhem, Department of Radiotherapy, Arnhem, The Netherlands ; 12 St James's University Hospital, Leeds Cancer Centre, Leeds, United Kingdom ; 13 UZ Leuven, Department of Radiation Oncology, Leuven, Belgium ; 14 St. Olavs Hospital, Clinic of Oncology and Women's Clinic, Trondheim, Norway ; 15 Amsterdam University Medical Centers- University of Amsterdam, Department of Radiation Oncology, Amsterdam, The Netherlands ; 16 Leiden University Medical Center, Department of Radiation Oncology, Leiden, The Netherlands Purpose or Objective To examine risk factors associated with the occurrence of late diarrhoea in Locally Advanced Cervical Cancer (LACC) patients treated with radio(chemo)therapy and Image- guided adaptive brachytherapy (IGABT). Material and Methods From 2008 to 2015 a total of 1416 patients were enrolled in the prospective observational EMBRACE study (an international study on MRI-guided brachytherapy in LACC). Treatment combined external beam radiotherapy (EBRT) delivered as 45-50Gy in 25-30 fractions ±para-aortic node (PAN) irradiation and IGABT ±chemotherapy. Physician assessed (CTCAE v.3) and patient reported (EORTC) diarrhoea was evaluated at baseline and at regular follow- ups (FUPs). Potential patient- disease- and treatment- related risk factors were tested in univariate (UVA) and multivariable (MVA) analyses (Cox proportional hazards model) for crude incidence of moderate (CTCAE G≥2), severe (CTCAE G≥3) and “very much” (EORTC) diarrhoea (table 1). Binary logistic regression was used for analysis of persistence of diarrhoea, defined as mild and moderate if CTCAE G≥1 and G≥2 were scored in at least half of all FUPs, and analogue if patients reported ”quite a bit or worse” (substantial) diarrhoea in EORTC. EBRT lymph node (LN) irradiation was categorized according to boost/no boost, prescription dose and volume (V57Gy_categorized).

Conclusion Our prospective study demonstrates the impact of treatment technique on early morbidity (mainly PRO). This effect is transient, with recovery at 3-months FU. Dose-