ESTRO 38 Abstract book

S1181 ESTRO 38

differences of chronic toxicity (LT), local recurrence (LR), locorregional relapse (LRR) and survival free metastases (SFM). Material and Methods 102 patients who were diagnosed and intervened of endometrial adenocarcinoma Grade I (G), GII and localized G3, with IA and IIB stage, exclusively treated with endovaginal HDRBT, with cylinders, between 2008- 2015 with a minimum follow up of 30 months, were included in this retrospective analysis. Fédération Internationale de Gynécologie Obstétrique Stage (FIGO): IAa:37, IB:63, IIA:2. Brachytherapy: Group (Gp) I: 30 patients who received 5-6 fractions (fx)/3,8-4 Gy at 0,5 cm. surface cylinders, and Group II: 72 patients, who received 3fx/7Gy 0,5 surface cylinder. The mean days overall treatment time (OTT) was 11 and 8 respectively in Group I and II. Previously they had undergone hysterectomy plus salpingo-oophorectomy abdominal or assisted by laparoscopy ± lymphadenectomy. Toxicity vaginal, bladder and rectal was evaluated using Comoon Terminology Criteria for Adverse Events v4.03 (CTCAE). The equivalent dose at 2 Gy (EQD2) and bioequivalent dose (BED) study was performed in vaginal mucosa surface with α/β:3. The results from these two groups were then compared and analysed with SPSS 18. LT, LR, LRR, SFM and OS were compared in both groups and were analyzed with the SPSS 18. Survival (OS) was defined for Test Long Rank (Mantel-Cox). Results Histology of adenocarcinoma in 94 (92%), serous-clear cell in 6,8%. Well diferenciated 35%, moderated 60% and poorly 7%. Lymphovascular space invasion (LVSI) positive in 1 patient of Gp I. Grouped by risk group, low risk 34 (9GpI/25GpII), intermediate risk 40 (10/30), high- intermediate risk: 25 (10/15) and high risk: 3 (1/2). The EQD2 on the vaginal surface of Gp I patients was 72,19 Gy and Gp II: 95,42 Gy. The BED on the vaginal surface of Gp I patients was 120,32 Gy and Gp II 159,04 Gy. Late toxicity appeared in 14/102 (14%): vaginal 8 Grade 1, 3 Grade 2; bladder 2 Grade 2; rectal 1 Grade 1. With a mean and median follow-up of 69 and 72 months (range, 20–96), none patient had vaginal relapse. 5 of 102 patient had locoregional relapse, 2 in Gp I and 3 in Gp II. 6 patient had distant metastases, 2 in Gp I and 4 in Gp II. Of them, 2 dead in Gp1 and 3 in Gp II. No differences were found in relation to OTT, LR, SFM and OS in Groups I and II. No differences were found in LT to relation BED Groups I and II. Conclusion Six fractions of 3,8–4 Gy in 11 days or three fractions of 7 Gy in 8 days in patients receiving exclusive HDRBT was a safe treatment in relation to late toxicity, local and locorregional control and survival free metastases, but the 3-fractions scheme increases the comfort of the medical team and the patient by reducing the number of times they go to the hospital. EP-2136 Brachytherapy study between patients treated with HDR Ir-192 and Xoft 50kVp source for uterus cancer K. Asiev 1 , S. Devic 2 , B. Bahoric 3 1 Jewish General Hospital, Radiation Oncology Department G18.123, Montreal, Canada; 2 Jewish General Hospital, Radiation Oncology Department G18.121, Montreal, Canada; 3 Jewish General Hospital, Radiation Oncology Department G.002, Montreal, Canada Purpose or Objective To evaluate the possibility of treating patients with low- energy electronic 50kVp brachytherapy beam modality instead of present standard of care High-Dose-Rate Brachytherapy (HDRBT) Ir-192 source for patients with uterus cancer.

Results We have constructed an 3.5/ 4 cm cylindrical applicator with beveled surface (antero-posterior direction) to fit the plane of cervix, of length 2.5 cm with unique 6 Fr catheter insertion points at fixed distances within the applicator (acting both as template for needle inserting/guidance and ovoid for IC loading). Three needles in anterior oblique direction parallel and in same plane of the Central tandem and 3 needles in lateral oblique direction for distal parametria could be placed technically on each side. Other needles used were straight needles to achieve adequate coverage. The distance of the oblique catheters from central tandem is more than 3 cm at point A. We devised a loading pattern that can give IC + IS type of distribution. Dummy plans was created to see coverage of HRCTV [Table 1].

Max Thickness (c.m)

Height (c.m) Vol (c.c) D90 (%) V90 %

volume Max width (c.m)

HRCTV A 5.6

3.9

5.3

45.5

114

98.2

HRCTV B 4.5

3.5

5.8

47.8

105.4 96.6

HRCTV C 5

4.5

5.1

25.3

127.3 98.4

Conclusion We have developed an IC+IS applicator capable of delivering dose up to > 3.5 cm from point A. A single cylinder functioning both as ovoid and template for interstitial needles makes the applicator easy to use. The needles used also do not need to be bent. The applicator will be clinically used after feedback from the scientific society. EP-2135 Exclusive brachytherapy in endometrial cancer: experience of an university hospital C. Salas 1 , L. Gutiérrez Bayard 1 , M.J. Macias Lozano 1 , S. Garduño Sánchez 1 , R. Rodríguez Sanchez 1 , S. Sayago Gil 1 , V. Díaz Díaz 1 , E. Gonzalez Calvo 1 , I. Villanego Beltran 1 , A. Ruiz Herrero 1 , M. Lorente Sanchez 1 , J. Jaén Olásolo 1 1 Hospital Universitario Puerta del Mar, Comprehensive Care Department Cancer- Radiation Oncology Service- University Hospital Puerta del Mar, Cadiz, Spain Purpose or Objective To analyze the impact of two different fractionation regimens of postoperative treatment through exclusive endovaginal Hight Dose Rate Brachytherapy (HDRBT) in women intervened for endometrial cancer, and find