ESTRO 36 Abstract Book

S683 ESTRO 36 2017 _______________________________________________________________________________________________

this approach in published international guidelines. Intervals from 1 to 4 weeks are associated with higher rates of postoperative complications. In this study we aim to evaluate toxicity, response to treatment and survival in patients with LARC treated with SC-RT in the neoadjuvant setting. Material and Methods Prospective inclusion of patients with LARC treated by SC- RT between 2002 and 2015. Response was assessed by pathological stage and Ryan modified tumor regression grade (TRG); toxicity was evaluated using CTCAE 4.0 scale. Survival curves were estimated using Kaplan-Meier’s method. A type I error of 0.05 was considered. Results 73 patients included, 63.0% male. Median age was 80 years, 31.5% with Karnofsky index lesser or equal to 80%. Tumor stage was cT3 in 80.9% and cT4 in 15% of patients; 58.9% were cN+. Perineal acute toxicity grade 2 was described in 2.7%, with no other toxicities. 68 patients underwent surgery with a median RT-surgery interval of 7 weeks (1-22 weeks). Conservative surgery was performed in 79.4% and postoperative complications observed in 33.8%. Complete pathological response (cPR) achieved in 7.4% of patients with TRG 0-1 in 8.9%. Lymphovascular invasion was observed in 23.5% of surgical specimens and R0 resections in 83.8%. 42 patients underwent surgery more than four weeks after the end of RT (61.7%), with a higher percentage of cPR than those submitted to surgery before, although not statistically significant (3.8% vs. 9,5%). This group also achieved TRG 0-1 more often (3.8% vs. 12.2%). Postoperative complications were higher in the group that underwent surgery up to 4 weeks (42.3% vs. 28.6%), without statistical differences. With a median follow-up of 27 months, at 5 years, locoregional-disease- free survival (LRDFS) was 88.7%, disease-free survival (DFS) was 68.1%, cancer-specific survival (CSS) was 60.8% and overall survival (OS) was 37.0%. Although not statistically significant, cPR showed better outcome at 5 years on LRDFS (100% vs. 87.7%), DFS (100% vs. 65.3%) and CSS (100% vs. 57.5%). Conclusion In this set of patients, SC-RT was a good option for LARC neoadjuvant treatment, particularly given patient’s age and co-morbidities. Although not statistically significant, delayed surgery (over 4 weeks) was associated with a higher cPR rate. In the group of patients with cPR, no local recurrence or distant metastasis were registered. In patients undergoing surgery up to 4 weeks, the higher rate of surgery-related complications may be explained by the existence of surgeries performed in the second and third weeks after RT. EP-1284 Impact of surgical delay after long-course radiochemotherapy in rectal cancer T.M. Dos Santos Teixeira 1 , A. Ponte 1 , J. Casalta.Lopes 1 , I. Nobre-Góis 1 , M.R. Silva 2 , R. Lebre 3 , A. Barros 3 , M. Borrego 1 1 Hospitais da Universidade de Coimbra, Serviço de Radioterapia, Coimbra, Portugal 2 Hospitais da Universidade de Coimbra, Serviço de Anatomia Patológica, Coimbra, Portugal 3 Hospitais da Universidade de Coimbra, Serviço de Oncologia Médica, Coimbra, Portugal Purpose or Objective One of the possible treatments for locally advanced rectal carcinoma (LARC) in the neoadjuvant setting is long course radiotherapy, associated to concomitant chemotherapy (LC-RCT). There is growing evidence that a longer interval between radiation therapy and surgery improves tumor response to LC-RCT. Randomized studies have shown that the achievement of a complete pathological response provides a decrease in local recurrence and an improvement in overall survival. In this study we aim to evaluate the impact of delayed

surgery in pathologic complete response rate after neoadjuvant therapy with LC-RCT. Material and Methods Prospective inclusion of patients with LARC, clinically staged as cT3 or cT4, treated with LC-RCT between 2002 and 2015, with a dose of 50.4Gy / 28 fractions / 5.5 weeks and undergoing surgery afterwards. The response to neoadjuvant therapy was assessed by pathological stage and toxicity was evaluated by using CTCAE 4.0. Survival curves were estimated using Kaplan-Meier’s method. A type I error of 0.05 was considered. Results 249 patients included, 64.7% male. Median age was 64 years, 95.2% of patients with Karnofsky index greater than or equal to 90%. Tumor stage was cT3 in 83.9% of patients and cT4 in 16.1%; 90.4% had lymph nodes with criteria for tumor infiltration. During the treatment acute toxicity was observed in 75.1% patients, with 10.0% corresponding to grade 3 or 4. Concomitant chemotherapy was mainly administered using oral fluoropyrimidines (84.7%). 73 patients (29.3%) underwent surgery over 8 weeks after the end of LC-RCT. 67.1% of patients underwent conservative surgery; there were no differences in postoperative complications regarding time to surgery. Patients undergoing surgery over 8 weeks after the end of LC-RCT showed higher T downstaging (65.8% vs. 56.8%) and pathological complete response (pCR) rate (16.4% vs. 13.1%), although no statistically significant differences were observed. With a median follow-up of 57 months, at 5-years, locoregional-disease-free survival (LRDFS) was 93.4%, disease-free survival (DFS) was 69.5%, cancer- specific survival (CSS) was 77.5% and overall survival (OS) was 70.6%. Patients achieving pCR had better DFS (5-year: 93.3% vs. 65.3%, p=0.003), CSS (5-year: 96.7% vs. 74.5%, p=0.006) and OS (5-year: 88.9% vs. 67.8%, p=0.010). Although not statistically significant, LRDFS was also higher in this group (5-year 100% vs. 92.3%, p=0.100). Conclusion Although not significantly, delaying surgery over 8 weeks provided greater T downstaging rate and pCR, with no differences regarding postoperative complications. pCR showed significant impact on the DFS, CSS and OS. EP-1285 Neutrophilia in locally advanced cervical cancer: biomarker for image-guided adaptive brachytherapy? C. Chargari 1 , A. Escande 1 , C. Haie-Meder 1 , P. Maroun 1 , S. Gouy 2 , R. Mazeron 1 , T. Leroy 3 , E. Bentivegna 2 , P. Morice 2 , E. Deutsch 1 1 Gustave Roussy, Radiotherapy department- Brachytherapy unit, Villejuif, France 2 Gustave Roussy, Department of surgery, Villejuif, France 3 Oscar Lambret Cancer Center, Radiotherapy department, Lille, France Purpose or Objective To study the prognostic value of leucocyte disorders in a prospective cohort of cervical cancer patients receiving definitive chemoradiation plus image— guided adaptive We examined patients treated in our Institution between April 2009 and July 2015 by concurrent chemoradiation (45 Gy in 25 fractions +/– lymph node boosts) followed by a magnetic resonance imaging (MRI)-guided adaptive pulse- dose rate brachytherapy (15 Gy to the intermediate-risk clinical target volume). The prognostic value of pretreatment leucocyte disorders was examined. brachytherapy (IGABT). Material and Methods Electronic Poster: Clinical track: Gynaecological (endometrium, cervix, vagina, vulva)