ESTRO 2021 Abstract Book

S81

ESTRO 2021

2020 the IDMC after interim analysis and due to promising results advised to stop accrual of patients and report surgical tolerability. Results From July 2015-june 2020, 144 patients were included in the trial. All data are blinded. Compliance to treatment was good in > 90%. Median follow-up time was 24 months (range 8-60). Table gives main clinical outcomes. TME was performed in 30 pts, always before 2 years. Anterior- resection: 21pts (70%), ypT0: 3pts (10%), R0:28pts (93%), ypN0:21 pts (70)%. Median Hospital stay: 9.5 days, Second surgery: 3 (10%), Medical toxicity: 4pts (13%), Death 30 days : 0. A local excision was performed in 25 pts always before 18 months.ypT0:7pts ( 28%), R0: 21 pts (84%).Mean Hospital stay: 3 days, Death 30 days : 0.

Conclusion After high dose CRT ±CXB boost, surgery (TME or local excision) can be successfully performed with expected tolerability in patients not achieving cCR or developing local recurrence. The higt rate of local control achieved in T2-3 < 3cm rectal cancer confirms OP as a good treatment approach to be discussed in MDT and with well-informed patients. PH-0111 Impact of body-mass index on multimodal treatment and outcome in locally advanced rectal cancer M. Diefenhardt 1 , E.B. Ludmir 2 , R. Hofheinz 3 , M. Ghadimi 4 , B. D. Minsky 5 , M. Fleischmann 1 , E. Fokas 1 , C. Rödel 1 1 University of Frankfurt, Department of Radiotherapy and Oncology, Frankfurt, Germany; 2 The University of Texas MD Anderson Cancer Center, Division of Radiation Oncology,, Houston, USA; 3 University Hospital Mannheim, Department of Medical Oncology, Mannheim, Germany; 4 University Medical Center, Department of General, Visceral and Pediatric Surgery, Göttingen, Germany; 5 The University of Texas MD Anderson Cancer Center, 2Division of Radiation Oncology, Houston, USA Purpose or Objective The global rise in the number of obese patients is emphasizing the need to better understand the impact of body-mass index (BMI) on the course of multimodal therapy and oncologic outcomes in rectal cancer patients. Materials and Methods Correlations of BMI with pretreatment clinical, surgical and pathological characteristics, toxicity and treatment adherence using the Pearson’s Chi-squared test or logistic regression were analyzed in the CAO/ARO/AIO-04 III trial cohort (n=1236) that assessed the role of oxaliplatin included in a modified fluorouracil-based neoadjuvant chemoradiotherapy (CRT) regimen. One- way ANOVA was used to analyze correlation of immune blood cell counts and BMI. The prognostic role of BMI was examined with the logrank test plotted using Kaplan-Meier. Results Obese patients had a better ECOG performance status (P=0.027), less acute organ toxicity (P=0.036), but showed poorer neoadjuvant treatment adherence (P=0.013) and were less likely to undergo sphincter preserving surgery (P=0.01). Post-surgical complications did not differ significantly between BMI classes, whereas underweight was associated with an increased neutrophil cell count (P=0.042) and with poorer TME quality (P=0.034). After a median follow-up of 50 months, 3-years DFS did not differ significantly between obese [73.0% (CI 95%, 67.5%-78.5%)] and normal weight [75.3% (CI 95%, 70.8-79.8%)] (P=0.926), but was significant worse in underweight patients [58.7 % (CI 95%, 44.6-72.8%)] (P=0.029). When analyzed by sex, only underweight men showed worse DFS (P=0.001). Conclusion In our study, obesity was associated with an increased risk of abdominoperineal resection and poorer adherence to neoadjuvant treatment without compromising oncological outcome, whereas underweight men showed worse DFS. PH-0112 Multicenter large retrospectIve database on SBRT for colorectal lung metastases: the LaIT-SABR study L. Nicosia 1 , D. Franceschini 2 , F. Perrone Congedi 3 , F. Casamassima 4 , M.A. Gerardi 5 , M. Perna 6 , V. Scotti 6 , A. Fodor 7 , R. Mazzola 1 , M. Rigo 1 , A. Iurato 8 , F. Pasqualetti 9 , G. Gadducci 9 , S. Chiesa 10 , R.M. Niespolo 11 , A. Bruni 12 , L. Frassinelli 12 , P. Borghetti 13 , A. Di Marzo 14 , A. Ravasio 15 , B. De Bari 16,17 , M. Sepulcri 18 , D. Aiello 19 , G. Mortellaro 20 , C. Sangalli 21 , M. Franceschini 21 , G. Montesi 22 , F.M. Aquilanti 23 , R. Valdagni 21 , I. Fazio 19 , L. Corti 18 , L. Vavassori 15 , E. Maranzano 14 , S.M. Magrini 13 , F. Lohr 12 , S. Arcangeli 11 , V. Valentini 24,25 , F. Paiar 9 , S. Ramella 8 , N.G. Di Muzio 7,26 , L. Livi 6 , B.A. Jereczek-Fossa 27,28 , M.F. Osti 3 , M. Scorsetti 2 , F. Alongi 1,29 1 IRCCS Sacro Cuore Don Calabria Hospital, Cancer Care Center, Advanced Radiation Oncology Department, Negrar, Italy; 2 IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Department of Radiotherapy and Radiosurgery, Milan, Italy; 3 "Sapienza" University, Sant'Andrea Hospital, Via di Grottarossa