ESTRO 38 Abstract book

S760 ESTRO 38

the TVB dose below this threshold. The threshold of TVB V30 was 78.9%; the incidence of HT3+ could be reduced from 36.4% to 20.4% by maintaining the TVB dose below this threshold. Over age 61 years, concurrent chemotherapy with platinum plus taxane increased the incidence of HT3+. Conclusion The occurrence of HT in esophageal squamous cell carcinoma was associated with age, chemotherapy regimen, and TVB V30 and V40. Limiting the TVB dose and adjusting the chemotherapy regimen could reduce occurrence of HT3+. EP-1396 the role of multidisciplinary team in radiotherapy for esophageal cancer S. Zhao 1 , S. Wang 1 , F. Xu 1 , Y. Han 1 , W. Qi 1 , K. Youlia 2 , J. Chen 1 1 Ruijin Hospital- Shanghai Jiaotong University School of Medicine, radiation oncology, Shanghai, China ; 2 Institut Curie, radiation oncology, Paris, France Purpose or Objective To assess the effects of multidisciplinary team(MDT) on outcome of patients with esophageal cancer(EC) who had underwent radiotherapy, using propensity score matching. This is a retrospective cohort study Material and Methods We collected all patients diagnosed with EC in radiation oncology department at our institution from January 2015 to May 2017. The patients were divided into groups by those who were presented and not presented at MDT meeting(MDT and non-MDT). Propensity-score matching was applied at a ratio of 1:1 comparing the two groups.

re-canalization [5 in PVT & 1 in IVC]. Post-CK, 8% patient underwent TACE and 4% had TARE. Mild GI toxicities (Gr- 1-II) in 10 (40%), fatigue (Gr II-III) 7 (28%). One (4%) patient had Gr III GI toxicity and one (4%) patient had decompensation (<4wk) after treatment. Gender (p- 0.542), infective etiology (p-0.356), alcohol intake (p- 0.983), pre-CK AFP (p-0.581), BCLC stage (p-0.660), adjuvant Sorafinib (p-0.324) did not influence survival functions. Patients with PVT response (p-.003) had better survival. 1-yr actuarial OS in dose delivered (<39Gy Vs >39Gy: 65% vs 40%); CLIP Score (1-2 Vs 3-6: 75% Vs 40%); CP Score (5-7 Vs 8-9: 78% Vs 42%) & PVT Score (VP1-2 Vs 3-4: 67% Vs 56%) showed trend towards improved survival. Conclusion CyberKnife is safe & effective option in Indian HCC with PVT patients. Good PVT response, higher dose delivered, CP score, CLIP Score and PVT score have prognostic significance. RT dose and PVT response may be included in response assessment scoring system. EP-1395 Radiation Dose to the Thoracic Vertebral Bodies is Associated with Acute Hematologic Toxicities F. Lingli 1 , D. Xiaobo 1 1 Mianyang Central Hospital, Oncology, Mianyang, China Purpose or Objective Mean thoracic vertebral body(TVB) dose and low-dose parameters (V5–V20) are associated with severe acute hematologic toxicities(HT)during concurrent chemoradiotherapy (CRT) for lung cancer, in which optimal dosimetric cut-off points have been identified. Esophageal cancers are closer to TVBs than lung cancer and require longer radiation fields and different chemotherapy regimens. The optimal dosimetric cut-off points for TVBs in lung cancer maybe unsuitable for esophageal cancers. We aimed to explore factors associated with HT during CRT and optimal dosimetric cut- off points for TVBs in esophageal cancer. Material and Methods From January 2010 to June 2018, we selected patients with esophageal squamous cell carcinoma confirmed by pathology. We retrospectively examined radiotherapy plans for all patients who met the criteria and outlined the TVB dose for each patient. Average TVB dose and parameter data of V5–V60 were recorded on the dose- volume histogram diagram. Weekly blood routine results were recorded from the start of CRT to 2 weeks after the end of radiotherapy. At the same time, baseline data of age, ECOG score, body mass index, clinical stage, tumor length, induction chemotherapy, concurrent radiotherapy regimen, radiation dose, and radiotherapy modality were recorded. Simple logistic regressions were used to determine the correlation of all clinical and dosimetric parameters with HT. Multiple logistic regression models included dosimetric parameters and other variables with P≤0.3 on univariate analysis. The receiver operating characteristic (ROC) curve was used to analyze optimal dose limiting points. Results A total 126 patients were included (90 males and 36 females), with average age 60 years. Only 7 (5.6%) patients received induction chemotherapy; the rest received CRT. A total 103 patients (81.7%) received intensity-modulated treatment. Of all patients, 53 (42.1%) received platinum plus taxane, 66 (52.4%) platinum plus fluorouracil, and 7 (5.5%) other regimens. The median radiotherapy dose was 60Gy (50–70Gy). Hematological toxicity grade 3 and above (HT3+) occurred in 34 of 126 patients, with incidence 27.0%. The average TVB dose was 32.65 Gy, V5 70.06%, V10 67.03%, V15 65.13%, V20 63.32%, V30 59.06%, V40 50.05%, V50 28.18%, and V60 8.48%. Age, concurrent chemotherapy regimens, TVB V30 and V40 were associated with HT(P<0.05). The threshold of TVB V40 was 35.75% for HT3+ occurrence; the incidence of HT3+ could be reduced from 29.7% to 15.9% by maintaining

Results There were totally 212 patients analyzed, 157 with MDT and 55 non-MDT. In the unmatched population, there was no difference in patients and tumor characteristic between two group. In treatment options, the patients with MDT had significantly more in receipt of chemotherapy than non-MDT group(84.7% vs. 69.1%; x2= 6.373; P=0.012). In MDT group, there were longer median overall survival (OS) (P=0.025) than in non-MDT group, as well as in subgroup analysis for the patients with PS status 0-1(P<0.05), with SCC(P<0.05), stage I-II(P<0.01), high- middle differentiation(P<0.01), with surgery(P<0.01). After propensity score matching for the similar characteristics including the treatment option, patients with phase I-II stage or high-middle differentiation had better survival in MDT group(P<0.01, P<0.05). MDT was an independent predictor of receiving chemotherapy obtained in the regression analysis(OR, 2.827; 95% CI, 1.218-6.558).