ESTRO 37 Abstract book

S1227

ESTRO 37

EP-2219 Clinical outcome and late toxicity of MRI- based brachytherapy in cervical cancer patients K. Poksawat 1 , P. Alisanant 1 , N. Amornwichet 1 , K. Shotelersuk 1 , C. Khorprasert 1 1 King Chulalongkorn Memorial Hospital- Chulalongkorn University, Radiation oncology, Pathumwan, Thailand Purpose or Objective To assess the clinical outcomes and late toxicities in cervical cancer patients who had been treated with MRI- based Image guided adaptive brachytherapy (IAGBT) at our institution. Material and Methods A total of 138 patients with stage IB2-IVB cervical cancer treated with curative radiation between July 2012 – December 2015 had been consecutively reviewed in this study. All data were retrospectively collected. The treatment protocol was the external beam radiation (EBRT) 45-50.4 Gy with or without concurrent platinum based chemotherapy, follow by high dose rate brachytherapy 8 Gy x 3 fractions or 7 Gy x 4 fractions. MRI based planning was applied for each fraction of brachytherapy, in order to contour the high risk CTV (CTV HR ) and organs at risk (OARs, including rectum, sigmoid and bladder). Dose volume parameters were evaluated for CTV HR and OARs. The planning aims were 85-95 Gy (EQD210) for CTV HR D90, < 70-75 Gy for D2cc of rectum, < 75 Gy for D2cc of sigmoid and < 90 Gy for D2cc of bladder in EQD23. We analyzed local control (LC) which is the primary endpoint, overall survival (OS), progression free survival (PFS) and late toxicities (CTCAE v4.03). Results The median follow-up time was 27 months (range 7-58 months). FIGO stage was IB2: 3, IIA: 9, IIB: 75, IIIA: 3, IIIB: 25, IVA: 7 and IVB: 16. The mean tumor width was 4.5 cm (range 2-8 cm). 111 patients (80.4%) had squamous cell carcinoma and 51 patients (37%) had lymph node involvement. Interstitial technique combined with intracavitary brachytherapy was used in 97 patients (70.3%). Mean CTV HR D90 (EQD210) was 91.1 ± 6.5 Gy and mean D2cc (EQD23) were 68.7 ± 8.3 Gy for rectum, 67.0 ± 6.7 Gy for sigmoid and 81.3 ± 9.2 Gy for bladder. The majority of patients received concurrent chemotherapy (87%). Overall local control was 92.4% at 2 years. The 2-year PFS and OS were 76.4% and 88.9%, respectively. G1-2/G3/G4 toxicity for rectum was 18.1%/2.2%/0.7%. G1-2/G3 toxicity for bladder was 8.7%/2.9%. Conclusion The use of MRI-based IAGBT including interstitial insertion is achievable with good clinical outcomes, in particular of local control in locally advanced cervical cancer with minimal treatment related morbidity. EP-2220 Efficacy and dosimetry of 125I seeds implantation for recurrent cervical cancer after radiotherapy A. Qu 1 , J. Wang 1 , H. Sun 1 , W. Jiang 1 , Y. Jiang 1 , S. Tian 1 1 Peking University Third Hospital, Radiation Oncology, Beijing, China Purpose or Objective To evaluate the efficacy of radioactive 125 I seeds implantation for pelvic recurrent cervical cancer after radiotherapy. The clinical factors and dosimetric factors affecting treatment outcome further to be analyzed. Material and Methods A retrospective analysis was made on 36 patients with pelvic recurrent cervical cancer after radiotherapy from July 2005 to October 2015 in our hospital with 125 I seeds implantation, under ultrasound or CT guidance. Treatment planning was performed before implantation to estimate the number, activity of the seeds. The seeds numbers ranged from 10-140 with a median numbers of

62.5, and the activity of seeds ranged from 0.5-0.8 mCi with a median activity of 0.7mCi. Dosimetric verification was performed using CT scan immediately after 125 I seeds implantation. D 90 、 D 100 、 V 100 、 V 150 、 and V 200 were evalued by postoperative plan. The Kaplan-Meier method was used to calculate the local progression free survival (LPFS) rate and overall survival (OS) rate. The Log-rank test and Cox regression were used for univariate and multivariate analyses. Results The median followup time was 11.5 months （ 2-30 months ） . 24 cases had different degree of local pain before treatment. The pain relief rate was 79.2% （ 19/24 ） . The short-term effective rate is 88.9% （ 32/36 ） . 1 year LPFS rate was 34.9%. 31 cases died, and 22 cases died from the cancer (61.1%). 1 year OS rate was 52%. The univariate analysis showed the location of recurrence (P<0.05), volume of lesion (P <0.01) and D 90 (P<0.05) were significantly correlated with LPFS. Multivariate analysis showed that the location of the recurrence and the invasion of ureter were significantly related to LPFS. The 1-years LPFS of pelvic wall recurrence and central recurrence were 69.3%, 26.7% (P<0.05), respectively. Vaginal fistula occurred in 1 case lead from adverse effects. No other sever adverse effects. 33 cases were entered in dosimetric analysis. D 90 was 128.5 + 47.4Gy, D 100 was 50.4 + 23.7Gy, and V 100 was 86.7% +12.9%. Univariate analysis showed that D 100 was significantly associated with LPFS (P =0.004). D 100 > 50Gy is an important factor affecting LPFS (P =0.005). Conclusion Radioactive 125 I seeds implantation was a safe, effective, minimally invasive salvage treatment for pelvic recurrent cervical cancer after radiotherapy. It could obviously alleviate the pain and improve the quality of life. Recurrence of pelvic wall disease treated with radioactive 125 I seeds implantation was superior to central recurrence. Tumor volume, ureteral involvement or not could affect the local control. D 100 > 50Gy could significantly improve LPFS, which may predict the local control. Since the patients undergone multiple treatment cycles after relapse, the advantages of effect were not apparent compared with other treatments, and further studies were needed. EP-2221 Overweight is associated with pelvic nodal failure after chemoradiation in cervical cancer patients A. ESCANDE 1,2 , S. Bockel 2 , E. Manea 2 , A. Schernberg 2 , R. Mazeron† 2 , E. Deutsch 2 , I. Dumas 2 , P. Morice 3 , C. Haie- Meder 2 , C. Chargari 2 1 Centre Oscar Lambret, Academic Department of Radiation Oncology, Lille, France 2 Gustave Roussy, Brachytherapy Unit-Radiotherapy Department, villejuif, France 3 Gustave Roussy, Surgery Department, villejuif, France Purpose or Objective Numerous preclinical and clinical data suggest that metabolism disorders could modify the response to radiotherapy and therefore on the clinical outcome. However, the true impact of obesity in cervical cancer patients (pts) is uncertain. We investigated the prognostic value of body mass index (BMI) in locally advanced cervical cancer (LACC) pts homogeneously treated according to modern standard of chemoradiation followed with image guided adaptive brachytherapy (IGABT). Material and Methods Clinical records of consecutive pts treated in our institution between 2004 and 2016 were examined. All pts were treated by external beam radiation therapy (45 Gy in 25 fractions in the pelvis +/- para-aortic lymph nodes +/- boost delivering total dose of 60 Gy to