Abstract book - ESTRO meets Asia

S97 ESTRO meets Asia 2018

Clinical: Gynaecological

PO-236 A phase II trial of recombinant human endostatin combined for patients with cervical cancer M. Fan 1 , J. Yang 2 , J. Wang 1 , J. Wang 1 , J. Ma 1 , R. Li 1 , M. Chen 1 , L. Sun 1 1 Sichuan Cancer Hospital, Radiation Oncology, Chengdu, China 2 Sichuan Cancer Hosptial, Radiation Oncology, Chengud, China Purpose or Objective Concurrent cisplatin-based chemoradiotherapy (CRT) is the standard treatment for locally advanced cervical cancer. Patients with lymph node metastasis and bulky tumor were associated with poor prognosis. RTOG 0417 trial demonstrated the safety and efficacy of additional bevacizumab to standard CRT in definitive setting. Recombinant human endostatin (Endostar) is an anti- angiogenesis target drug, which had been approved for the treatment of advanced non-small cell lung cancer in China. It was designed to inhibit the formation of vascular endothelial cell migration, thereby inhibiting tumor proliferation. We conducted this trial to explore the safety and efficacy of Endostar combined with definitive CRT for locally advanced cervical cancer. Material and Methods Patients with stage IIB-IIIB cervical cancer and have at least one of the risk factors--bulky tumor and/or positive lymph node are eligible for this study. Bulky tumor is defined as tumor diameter>4cm, while positive lymph node is defined as shortest diameter over 1 cm in CT/MRI images or confirmed by PET-CT. Eligible patients will receive 46Gy pelvic irradiation and 4 times of brachytherapy. Positive nodes will received total dose of 60Gy. Concurrent chemotherapy is cisplatin 40mg/m2 weekly for 5 cycles. Endostar is prescribed with 7.5mg/m2 civ d1-14, repeat every 21 days. The primary end point is safety using CTCAE criteria and preliminary efficacy.Our hypothesis is that endostar can improve ORR of cervical cancer patients without increasing toxicities. Clinical trial identification: ChiCTR-OIC-17012754, released on Nov 1, 2017 Results 12 patients have been enrolled and 9 patients have already successfully completed the treatment and were evaluated as CR. No Grade 3 or higher toxicity happened during radiation, 1 patient felt mild heart discomfort. No serious toxicity that need to suspend treatment happened. Conclusion The preliminary results indicated that Endostar combined with concurrent chemo-radiation was safe and efficacy, but still needs more data to be verified. PO-237 Prophylactic extended-field irradiation for patients with cervical cancer W. Wang 1 , H. Ke 1 , Z. Fuquan 1 1 Peking Union Medical College Hospital, Radiation Oncology, Beijing, China Purpose or Objective To evaluate the efficacy and toxicity of prophylactic extended-field radiation therapy (EFRT) for cervical cancer patients treated with concurrent chemoradiotherapy (CCRT). Material and Methods Cervical cancer patients without para-aortic metastatic lymph nodes (MLNs) and treated with definitive radiotherapy or CCRT between January 2011 and December 2014 were reviewed. Patients were classified into pelvic radiation therapy (PRT) group and EFRT group. An additional dose of 50.4Gy in 28 fractions was delivered to para-aortic lymph nodes regions for patients in EFRT group. Cox regression and propensity-score matching (1:1) were used to compare the overall survival (OS), disease-

PO-235 3D-CRT versus Conventional Techniques in External Beam Radiotherapy of Cancer Cervix V. Kumari 1 , S. Pradhan 1 , A. Mourya 1 , T.B. Singh 2 , L.M. Aggarwal 1 , A. Verma 3 , S. Pal 1 1 Institute of Medical Sciences- Banaras Hindu University-, Radiotherapy and Radiation Medicine-, Varanasi-221005, India 2 Institute of Medical Sciences- Banaras Hindu University-, Division of Biostatistics-, Varanasi-221005, India 3 Institute of Medical Sciences- Banaras Hindu University-, Radiodiagnosis and Imaging-, Varanasi-221005, India Purpose or Objective Carcinoma cervix is primarily seen in developing countries with limited resources. Although newer radiotherapy (RT) techniques have evolved, many centres in 3rd world countries still lack IMRT and VMAT facilities. The study aims to compare dosimetric parameters of conventional and 3D-CRT techniques, in external beam RT for cancer cervix. Material and Methods Thirty-eight carcinoma cervix patients underwent CT simulation under strict bladder and rectal protocols. Target volumes on axial CT sections were delineated, in consultation with a radiologist, as per PGI guidelines for intact carcinoma cervix (Bansal et al, 2013). OAR was contoured as per RTOG guidelines. Plans were generated using ECLIPSE version 11.0 Treatment Planning System for a dose of 46Gy in 23 fractions. Patients also received brachytherapy. Patients were treated by 3D-CRT field in field technique with 2 pairs of parallel opposed fields (AP- PA and Lateral) aiming coverage of V95%=100% of PTV with no PTV area receiving >107% prescribed dose. Two conventional plans, i.e. one 4 field box (4F-B) and one 4 field box with corner shielding (4F-C), were also generated for each patient. Conventional fields were defined by bony landmarks on digitally reconstructed images. The field borders were: (i) AP-PA fields-superiorly at L4-L5 intervertebral space, inferiorly at lower border of obturator foramen or 2cm below lowest disease extent and laterally 1.5cm lateral to pelvic brim, (ii) Lateral fields- anteriorly at anterior border of pubic symphysis, posteriorly at S2-S3 intervertebral bony landmarks. Dosimetric parameters of PTV and OARs were computed and compared. Results V95% and V98% for PTV was superior for 3D-CRT than conventional plans, i.e. 4F-B and 4F-C (99.94% vs 87.83% & 85.41% and 91.1% vs 81.52% & 76.88%, respectively) and 4F-B was better than 4F-C in this regard. All plans were similar when V107% was compared. 3D-CRT had better Conformity Index (CI)- 0.93 vs 1.61 & 1.14 and Homogeneity Index (HI-as per ICRU 83)- 0.07 vs 0.89 & 0.87, than 4F-B and 4F-C. Again, 4F-C had better conformity than 4F-B. There was no difference in bladder sparing at low doses but at V46Gy, 3D-CRT was better than 4F-B and 4F-C (p< 0.001 each). 3D-CRT was better in sparing rectum at all dose parameters except V46Gy, where 4F-C was better than 3D-CRT (p=0.043). Bowel sparing was better in 4F-C compared to both 4F-B & 3D- CRT in all respects. 3D-CRT resulted in significantly better femur sparing compared to conventional modalities. Conclusion In terms of PTV coverage, 3D-CRT was superior to conventional techniques. Better PTV coverage for 4F-B compared to 4F-C could be attributed to corner shielding as per bony landmark without considering PTV. Thus, corner shielding needs to be applied cautiously taking into consideration the PTV. The rectum, bowel and femur heads were spared better in 3D-CRT than conventional techniques and 4F-C was better than 4F-B.