ESTRO 36 Abstract Book

S688 ESTRO 36 2017 _______________________________________________________________________________________________

simulation CT images via image registration(MIM software) with bone matching, and by using Computational Environment for Radiotherapy Research (CERR) program, adequate margin covering 95% of combined vaginal cuff volume (MARGIN 95 ), rectum and bladder volume, and vaginal cuff movement were calculated. Patients were instructed to keep full bladder and empty rectum before radiotherapy. Results Average motion change in center of vaginal cuff in 10 patients was Left-Right (L-R) 0.5mm, Anterior-posterior (A-P) 2.2mm, and Superior-Inferior (S-I) 0.4mm, respectively. Correlation coefficient between rectal volume and stump Anterior movement was 0.762 (p < 0.001). Also, correlation coefficient between bladder volume and stump posterior movement, left movement was 0.346 (p = 0.014), 0.366 (p = 0.009), respectively. Mean value and standard deviation of MARGIN 95 was 6.7mm and 3.3mm respectively. Using T distribution, upper 5 percentage value of Margin 95 was 8.6mm Conclusion Although instructions were given to keep patient rectal volume consistent, large variations in rectal volume was observed. Also correlation between rectal volume and vaginal stump movement was strong(p <0.001). Laxatives and enema may be used to keep rectal volume constant to decrease magnitude of vaginal stump. Suggestive margin for vaginal cuff movement covering 95% of patients’ Margin95 is 8.6mm. EP-1295 Role of postoperative adjuvant radiotherapy in early stage cervical cancer without high risk factors W. Jung 1 , J. Kim 1 , Y.J. Kim 1 , J. Lee 1 , K. Kim 1 , S. Jeong 1 1 Ewha Womans University Medical Center, Radiation Oncology, Yangcheon-gu, Korea Republic of Purpose or Objective The aim of this study was to assess and evaluate the rate of adjuvant treatment following radical hysterectomy with pelvic lymphadenectomy in early stage uterine cervical cancer and to suggest the appropriate role of adjuvant radiotherapy among the patients without clinicopathologic high risk factors. Material and Methods The patients with FIGO stages IB-IIA uterine cervical cancer who underwent radical hysterectomy with pelvic lymphadenectomy between 2001 and 2012 were analyzed. Outcomes and clinicopathologic adverse features of patient groups were compared. High-risk feature was defined as lymph node metastasis, parametrial invasion, or resection margin status, and intermediate-risk feature was defined as tumor size, lymphovascular invasion or depth of invasion. Based on these factors, patients could be divided into high risk group and non-high risk group, and outcome according to adjuvant radiotherapy (RT) or not (non-RT) were evaluated. Results Total 85 (57.0%) of 149 patients received adjuvant radiotherapy after surgery. Five-year overall survival (OS) and disease-free survival (DFS) rates were significantly different between high-risk group and non-high risk group (86.0% and 78.0% in high-risk group vs 96.5% and 93.9% in non-high risk group). Among the non-high risk group patients, status more than 2 intermediate-risk factors were statistically associated with lower 5yr OS rate (p=0.043, HR 9.219, 95% CI 1.076-78.976). In subgroup analysis among the patients with 2 or more intermediate- risk factors, patients who did not receive adjuvant RT showed significantly lower 5yr OS rate compared to <2 risk factors (97.9% vs 81.8%, p=0.023), but patients who received adjuvant RT showed no difference (100% vs 96.8%, p=0.105). Conclusion This study was to re-evaluate the findings of risk factors and appropriate role of adjuvant radiotherapy. Adjuvant

radiotherapy is not only beneficial to patients with high- risk factors but also to patients with non-high risk factors, especially with more than 2 intermediate-risk factors. Therefore, adjuvant radiotherapy is still important and appropriate modality in patients with adverse features after radical surgery of uterine cervical cancer, despite of potential side effect caused by radiotherapy and desirable high rate of adjuvant treatment after radical surgery in early stage. EP-1296 Adjuvant radiotherapy in endometrial cancer: Volumetric Modulated Intensity Arc Therapy vs 3DRT C. Iftode 1 , A. Tozzi 1 , E. Clerici 1 , L. Di Brina 1 , G.R. D'Agostino 1 , A.M. Ascolese 1 , T. Comito 1 , D. Franceschini 1 , C. Franzese 1 , F. De Rose 1 , S. Tomatis 1 , P. Mancosu 1 , P. Navarria 1 , M. Scorsetti 1 1 Istituto Clinico Humanitas, Radiotherapy and Radiosurgery, Rozzano Milan, Italy Purpose or Objective To appraise the role of volumetric modulated arc (RapidArc, RA form) in the postoperative treatment of endometrial cancer patients. Material and Methods A retrospective analysis has been conducted on 36 patients treated with VMAT and image-guided RT (IGRT) since 2011 comparing treatment characteristics and outcome against a group of 24 patients treated with conformal therapy (CRT). Disease specific survival, local control and acute and late toxicity were scored and investigated as well as basic dosimetric characteristics of the treatments. Results Median age of patients was 64.4 yrs for VMAT and 68 yrs for CRT. All patients had Stage Ib-III. VMAT treatments lead to lower incidence of higher grade of toxicity events (all retrospectively retrieved from charts as worse events). No patient had G3 acute toxicity in both groups of treatment. G2 acute toxicity for patients treated with 3D versus VMAT was as follows: GU 29.17% vs 8.33%; GE 54.17% vs 25%; proctitis 25% vs 5.56%; cutaneous 25% vs 11.11%. Late toxicity in both treatment arms were limited. In the VMAT group 1 patient (2.78%) had G2 GU toxicity as in the 3D group; no patient treated with VMAT had GE G2 toxicity, meanwhile 3 cases (12.5%) were in 3D arm. No VMAT patient had proctitis, but in the 3D group there were 2 cases with G2 (8.33%) and one case (4.17%) of proctitis G3. No statistically significant differences were observed concerning survival or control. With a median FUP of 22.29 and 67.82 months for VMAT and 3D respectively, 4 patients had metastatic progression in the VMAT arm and in 3D arm 2 patients had loco-regional relapse and 3 metastatic progression. Conclusion The present study demonstrated that VMAT for adjuvant WPRT in endometrial cancer proved to be equally effective as CRT while improves the OAR dose sparing. A significant enhancement of acute toxicity support the use of VMAT technique in this setting of patients. EP-1297 Update: Phase III randomised trial on electro- hyperthermia plus chemoradiation for cervical cancer C. Minnaar 1 , J. Kotzen 2 , A. Baeyens 1 1 Johannesburg Hospital- Area 348, Radiobiology, Johannesburg, South Africa 2 Johannesburg Hospital- Area 348, Radiation Oncology, Johannesburg, South Africa Purpose or Objective Cervical is the second most common cancer in females in South Africa, with over 5000 new cases reported per annum. Improving outcomes with the addition of affordable radiosensitisers would assist in alleviating the socio-economic burden of the disease in South