ESTRO 35 Abstract Book

S110 ESTRO 35 2016 _____________________________________________________________________________________________________

schedule, adjuvant CT, surgery type, colostomy), (iii) tumor related (cT, cN, ypT, ycN, TRG grade, site of primary T). Results: From 2002 to 2005, 164 patients were enrolled (M: F = 104: 60); 83 were randomized to PLAFUR and 81 to TOMOX- RT. The median follow-up was 120.2 months (5.8-152.5). The 10-years rates of the efficacy endpoints, per arm, were as follows: LC: PLAFUR= 89.2% , TOMOX-RT= 96.3% (p=0.0757); MFS: PLAFUR= 81.9% , TOMOX-RT= 81.5% (p=0.987) ; DFS: PLAFUR= 78.3% , TOMOX-RT= 77.8% (p=0.982); OS: PLAFUR =50%, TOMOX-RT= 50% (p=0.918) TOMOX-RT showed a non-significantly higher rate of ypT0 compared to PLAFUR: 35.8% vs 24.1% (p = 0.102), respectively. Sphincter-saving surgery procedure was applied in: PLAFUR= 87.9%, TOMOX-RT= 86.4%. Grade 3-4 acute toxicity occurred in: 7.1% in the PLAFUR arm vs 16.4% in the TOMOX-RT arm. Confirmed predictors of outcome were found: - For LC: at univariate analisys= ypT; ypN, TRG Grade; at multivariate analysis= TRG Grade (p = 0.0126) - For MFS: at univariate analisys= age ypT, ypN and TRG Grade; at multivariate analysis= TRG Grade (p = 0.0255) - For DFS: at univariate analisys= age ypT, ypN and TRG Grade; at multivariate analysis= TRG Grade (p = 0.0224) - For OS: at univariate analisys= age ypT, ypN and TRG Grade; at multivariate analysis= no predictor was significantly associated. Conclusion: The TOMOX-RT schedule allowed higher non- significant local control, and comparable clinical outcome to the compared schedule. Moreover the ypT downstaging was significantly improved. Acute toxicity was comparable between arms. The TRG Grade was a good independent variable predicting LC, MFS and DFS, but not OS. OC-0244 Similar quality of life after short-course radiation versus chemoradiation in rectal cancer patients A.M. Couwenberg 1 , J.P.M. Burbach 1 , M. Van Vulpen 1 , M.P.W. Intven 1 , O. Reerink 2 , W.M.U. Van Grevenstein 3 , M. Koopman 4 , H.M. Verkooijen 5 Purpose or Objective: A majority of patients with rectal cancer is treated with neoadjuvant radiotherapy, with or without chemotherapy. If after chemoradiation (CRT) patients show a good clinical response, organ-preserving strategies are increasingly being offered. To increase the amount of patients with a good clinical response, it has been proposed to replace short-course radiotherapy (SCRT) by CRT. However, intensified treatment may affect patients’ quality of life (QoL). This study aims to compare self- reported QoL between routinely treated rectal cancer patients receiving SCRT versus CRT before, during and after treatment. Material and Methods: This multicenter prospective cohort study includes rectal cancer patients of all stages referred for radiotherapy between February 2013 and May 2015. QoL was assessed by EORTC-C30 and -CR29 questionnaires at baseline, 3, 6 and 12 months. For each patient, a propensity score (PS) for receiving CRT was calculated and used for restriction and adjustment. Changes in QoL over time were analyzed by mixed models between patients receiving CRT and SCRT, and additionally compared to a normative age- matched Dutch population. Results: After PS based restriction, 191 of 208 eligible patients were included, of which 69 underwent SCRT and 122 CRT. Patients undergoing CRT were younger (62.2 vs. 68.0 year), had more mesorectal fascia invasion (66.6% vs. 27.9%), 1 UMC Utrecht, Radiotherapy, Utrecht, The Netherlands 2 Isala, Radiotherapy, Zwolle, The Netherlands 3 UMC Utrecht, Surgery, Utrecht, The Netherlands 4 UMC Utrecht, Oncology, Utrecht, The Netherlands 5 UMC Utrecht, Imaging, Utrecht, The Netherlands

Conclusion: Based on the current results, analyzed on the current dataset, we have shown that the logistic regression model (separate model for every time point) may perform better than models trying to cover the complete follow-up period. This may be due to the optimization capabilities, when training a new model for every follow-up time point, but might be susceptible for overfitting. From a clinical perspective, this could be plausible as the influence of variables (e.g. (neo-)adjuvant chemotherapy) may vary during the follow-up period and targeted outcome and could show how clinical and/or treatment decisions have influence on the patient outcome over time. Future work also involves handling of missing values, which is a major concern when merging trial datasets. trial platin-based Radiochemotherapy in rectal cancer: 10-years analysis M. Gambacorta 1 , F. Cellini 1 , M. Colangione 1 , M. Lupattelli 2 , V. Lancellotta 2 , D. Genovesi 3 , M. Cosimelli 4 , V. Picardi 5 , M. Osti 6 , M. Portaluri 7 , F. Tramacere 7 , E. Maranzano 8 , G. Mantello 9 , V. Valentini 1 2 Università degli Studi di Perugia, Dipartimento di Radioterapia, Perugia, Italy 3 Università Gabriele D'annunzio, Dipartimento di Radioterapia, Chieti, Italy 4 Istituto Regina Elena, Dipartimento di Chirurgia, Roma, Italy 5 Centro Alta Tecnologia, Dipartimento di Radioterapia, Campobasso, Italy 6 Università La Sapienza - Ospedale S. Andrea, Dipartimento di Radioterapia, Roma, Italy 7 Ospedale Civile, Dipartimento di Radioterapia, Brindisi, Italy 8 Ospedale Civile, Dipartimento di Radioterapia, Terni, Italy 9 Azienda Ospedaliero-Universitaria Ospedali Riuniti- Università Politecnica delle Marche, Dipartimento di Radioterapia, Ancona, Italy Purpose or Objective: To investigate long term outcome and predictors between two schedules of platin based preoperative radiochemotherapy (RTCT) Material and Methods: Patients with rectal adenoca, MRI based stage cT3N0-N2, were randomized into two arms: 1) PLAFUR: RT= 50.4 Gy; Concurrent chemotherapy (CT)= CDDP 60 mg m2 (days 1-29) + 5FU continuous infusion in 96 h (days 1-4 and 29-32) 2) TOMOX-RT: RT=50.4 Gy; CT= Tomudex 3 mg / m2 + oxaliplatin 130 mg / m2 (days 1, 19 and 38). Restaging at 6-8 weeks after the end of RTCT, followed by surgery in 1-2 weeks. Adjuvant CT was recommended in ypN1-2. Local control (LC), metastases-free survival (MFS), disease- free survival (DFS) and overall survival (OS) were analyzed. Predictive endpoints of clinical outcome were tested by univariate and multivariate analysis. The investigated variables were: (i) patients (age, sex), (ii) therapy (RTCT on preoperative 1 Catholic University, Radiation Oncology - Gemelli ART, Rome, Italy OC-0243 Randomised