ESTRO 36 Abstract Book

S673 ESTRO 36 _______________________________________________________________________________________________

of Medical Sciences and Peking Union Medical College, Department of General Surgery, Beijing, China 5 Cancer Hospital-Chinese Academy of Medical Sciences, Department of Radiation Oncology, Beijing, China 6 Cancer Hospital-Chinese Academy of Medical Sciences, Department of Pancrea-gastric Surgery, Beijing, China 7 Chinese People's Liberation Army General Hospital, Department of Radiation Oncology, Beijing, China 8 Chinese People's Liberation Army General Hospital, Department of General Surgery, Beijing, China Purpose or Objective To evaluate the safety and efficacy of preoperative chemoradiotherapy and D2 radical resection in patients with locally advanced gastroesophageal junction carcinoma Material and Methods Gastroesophageal junction carcinomapatients withadenocarcinoma, clinical stage T3-4N0 or any TN1- 3M0, Siewert type II and III were enrolled. After exclusion of peritoneal metastasis with laparoscopic exploration, patients were randomly assigned into surgery group and preoperative chemoradiotherapy plus surgery group. The preoperative chemoradiotherapy group received intensity modulated radiation therapy (IMRT) and concurrent chemotherapyS-1 combined with oxaliplatin weekly plan. The prescription dose was GTV 50Gy/CTV 45Gy/25f/35d with concomitant boost. For the concurrent chemotherapy, S-1 was 30mg/m2 bid, five days a week; oxaliplatin was 40mg/m2 per week, with a total of 5 weeks.Laparoscopic exploration was needed 6 weeks after the end of the preoperative chemoradiotherapy. Patients with no peritoneal metastasis underwent D2 radical resection.Postoperative patients received SOX chemotherapy for 6-8 cycles. This trial (PAPER) is a multicenter randomized controlled studyin Beijing, Tianjin and Hebei Province. Primary endpoint is 3-year DFS, the secondary endpointsare safety and effectivity Results From Sep. 2014 to Jul. 2016,40 cases of 4 centers were enrolled. There were 20 patients in surgery group and 15 cases in the preoperative chemoradiotherapy group. The median age was 61 years (range 33-73).28 were male and 7 were female. Clinical staging were as follows: 20 cT3, 15 cT4; 4 cN0, 8 cN1, 19 cN2, 13 cN3. In the preoperative chemoradiotherapy group ,All patients completed radiotherapy. Six patients cannot tolerate concurrent chemotherapy due to toxicity.There was no grade 4 toxicity.The incidence of grade 3 toxicities were 13.3%: neutropenia. The incidence of grade 2 toxicities were 80%, including: thrombocytopenia (26.7%), neutropenia (6.7%) ,esophagitis and nausea(13.3%). All patients underwent radical D2 resection. Pathological complete response occurred in 13.3% (2/15) of patients. The T and N downstaging rate were 86.7% (13/15) and 100% (11/11). respectively. The tumor regression grade (TRG) were1 case of Grade 0, 2cases of Grade 1 and 3 cases of Grade 2, respectively. Surgery-related complications consisted of anastomotic leakage in 2 (13.3%), infection in 1 (6.7%) and hemorrhage in 1 (6.7%) patients. The perioperative mortality was nil. In the surgery group, Surgery-related complications consisted of anastomotic leakage in1 (6.7%), infection in 1 (6.7%) and hemorrhage in 1 (6.7%) patients. The perioperative mortality was nil Postoperative complications had no significant differences between two groups Conclusion Preoperative Chemoradiotherapy for patients with locally advanced gastroesophageal junction adenocarcinoma showed an acceptable toxicity, promising efficacy and safety for D2 resection. Further conclusions need to be verified by the mid-term results after the completion of

failure in terms of local control (LC) and metastasis-free survival (DMFS). Material and Methods We performed a multicenter retrospective study and we selected for this analysis 67 pts Antigen Lewis positive (prCA19.9 > 5U/ml), judged to be secretors of CA19.9. We used the Kaplan-Meier method and the log-rank test to investigate differences in LC and DMFS between groups defined based on clinical and pathological factors, different poCA 19.9 cutoff (37, 100 U/mL), paCA 19.9 cutoff (37 U/mL), and differences (%) between prCA19.9 and poCA19.9 levels. Results Demographic data and results are shown in Table 1. Median follow-up (FU) was 18 months (2-225). At univariate analysis, levels of poCA19.9 >37 U/ml (p= 0.009) or >100 (p< 0.001) and levels of paCA19.9 >37 U/ml (p= 0.009) were significantly associated with a worse DMFS. A change in prCA19.9 to poCA19.9 did not impact LC and DMFS. CRT did not impact pattern of failure in the whole patients population. Only in patients with poCA19.9 > 37 U/ml CRT significantly affected LC (63.6% for patients treated with CRT vs 40.0% for patients not treated with CRT; p = 0.008).

Conclusion Monitoring CA19.9 seems a useful parameter to modulate the management of PAC patients in terms of choice of adjuvant treatment and follow-up intensity. EP-1251 Safety and Efficacy of Preoperative Chemoradiotherapy in Patients with Locally Advanced EGJ Cancer Y. Li 1 , X. Li 1 , Y. Zhang 1 , J. Geng 1 , Y. Cai 1 , Z. Li 2 , K. Hu 3 , J. Yu 4 , J. Jin 5 , D. Zhao 6 , B. Qu 7 , L. Chen 8 , J. JI 2 1 Key laboratory of Carcinogenesis and Translational Research Ministry of Educati Peking University Cancer Hospital & Institute, Department of Radiation Oncology, Beijing, China 2 Key laboratory of Carcinogenesis and Translational Research Ministry of Educati Peking University Cancer Hospital & Institute, Gastrointestinal Cancer Center, Beijing, China 3 Peking Union Medical College Hospital-Chinese Academy of Medical Sciences and Peking Union Medical College, Department of Radiation Oncology, Beijing, China 4 Peking Union Medical College Hospital-Chinese Academy