ESTRO 2020 Abstract book

S233 ESTRO 2020

There were 402 patients with CMR after chemoradiation on FDG-PET (16% imaged with PET alone and 84% PET/CT): median age was 49 (23-86); Initial T stage was T1 (38%)/T2 (40%)/T3 (20%)/T4 (2%); median cervical tumor volume was 31 mL (1-347); initial FDG-avid nodal status was no nodes (50%)/pelvic lymph nodes (40%)/pelvic and para- aortic lymph nodes (10%); histology was squamous (84%)/non-squamous (16%). After a median follow up of 6 years (0.5-20), 109 (27%) recurred. The pattern of recurrence was pelvic (27%), distant (61%), or both (12%). In Cox modeling, no baseline or treatment factors were associated with pelvic failure. Distant recurrence was more likely in patients with T3-4 lesions (HR=2.4, 95% CI 1.5-3.8) and involvement of pelvic (HR=1.6, 95% CI 1.0- 2.7) or para-aortic lymph nodes (HR=2.7, 95% CI 1.4-5.0) at diagnosis. The 5-year FFR rates for T1-2 patients with no nodes, pelvic nodes alone, or para-aortic nodes at diagnosis were 85%, 76%, and 62%, respectively (p=0.04 between no nodes and para-aortic nodes). The 5-year FFR for T3-4 patients with no nodes, pelvic nodes alone, or para-aortic nodes at diagnosis were 68%, 56%, and 25%, respectively (p=0.09 between no nodes and para-aortic nodes). Conclusion Locally advanced (T3-4) cervical tumors and para-aortic nodal involvement at diagnosis are poor prognostic factors even after CMR following chemoradiation. Clinical follow- up is warranted for all patients after CMR. PH-0403 Correlation early morbidity with external beam dose volume parameters in loc. advanced cervix cancer Y. Seppenwoolde 1 , K. Majercakova 2 , E. Dörr 3 , M. Buschmann 3 , A. Sturdza 3 , R. Pötter 3 , D. Georg 3 1 Erasmus MC Cancer Center, Radiotherapy, Rotterdam, The Netherlands ; 2 Hospital de la Santa Creu i Sant Pau, Department of Radiation Oncology-, Barcelona, Spain ; 3 Medical University of Vienna, Department of Radiotherapy, Vienna, Austria Purpose or Objective Predicting external beam radiotherapy (EBRT) related morbidity based on dose-volume parameters (DVHs) remains an unresolved issue in definitive radiochemotherapy (RCT) for patients with locally 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

LASSO. Results

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.

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- 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