ESTRO 37 Abstract book

ESTRO 37

S399

Results For all patients, the median follow-up time was 30 months (0-133) and the median overall survival time (MST) was 37.9 months. The 3 and 5-year OS rates were 55.5% and 43.3% for patients who underwent boost irradiation (134 patients; boost group), respectively. Corresponding results for patients who did not undergo boost (128 patients; non-boost group) were 45.4% and 35.1%. In the UA, boost group had better OS than non- boost group ( p = 0.046; Figure 1) while the difference was not observed in the MA. For patients who underwent surgical resection (193 patients; 73.6% of whole cohort), MST was 56.6 months and the 3 and 5-year LC rates were both 89.8% for boost group (101 patients). Corresponding results for non-boost group (92 patients) were 78.3% and 74.5%. In the UA, boost group had better LC than non- boost group ( p = 0.005; Figure 2) and dose escalation was found out as a sole predictive factor for better LC in the MA (Hazard Ratio: 0.331, 95% confidence interval: 0.137- 0.725; p = 0.005).

Conclusion LINAC SBRT for adrenal metastasis is a safe and non- invasive technique with minimal toxicities. Adequate dose regimens seem to be important for local tumor control. We could achieve results that do well compared to the so far published literature. We saw a treatment response in more than 80% of the patients with radiological follow up, without any case of adrenal insufficiency. Nevertheless, overall and PFS is poor, due to the metastatic disease state. PO-0772 Impact of dose escalation to nerve plexus on the outcome of neoadjuvant CRT for pancreatic cancer T. Hirata 1 , T. Ikawa 1 , K. Wada 1 , N. Kanayama 1 , M. Morimoto 1 , K. Konishi 1 , H. Takahashi 2 , T. Teshima 1 1 Osaka International Cancer Institute, Radiation Oncology, Osaka, Japan 2 Osaka International Cancer Institute, Surgery, Osaka, Japan Purpose or Objective Neoadjuvant chemoradiotherapy (NACRT) for pancreatic adenocarcinoma (PC) reportedly has survival benefits. We have attempted to escalate doses irradiated to high risk areas of recurrence with a goal of further improvement of treatment outcome. The aim of this study was to evaluate the treatment outcome of NACRT for PC with a focus on effects of this strategy. Material and Methods We assessed 262 patients [male: 161, female: 101, median age: 66 (33-84)] with resectable or borderline resectable PC who underwent NACRT from January 2006 to September 2012. The delivered radiation dose was 50 Gy (2 Gy/fraction) to the primary tumor site, retroperitoneal soft tissue and surrounding regional nodal areas. We have added extra small fields for a 10 Gy (0.4 Gy/fr) simultaneous radiation boost to the roots of the celiac and superior mesenteric arteries, which have been recognized as high risk areas of recurrence (extrapancreatic nerve plexus invasion) since September 2009. Intravenous administration of Gemcitabine (1000 mg/m 2 ) was initiated concurrently on days 1, 8, and 15, every 4 weeks and generally repeated for 3 cycles. Re- evaluation of resectability was performed at the completion of the NACRT and patients whose PC did not show disease progression underwent surgical resection and subsequent liver perfusion chemotherapy. Patients who were thought to have high probability of recurrence underwent adjuvant chemotherapy. The impacts of dose escalation and other clinical factors (age, sex, performance status, clinical and pathological T and N stage, tumor location and adjuvant chemotherapy) on overall survival (OS) and locoregional control (LC) were investigated. Univariate and multivariate analyses (UA and MA) were performed by using generalized Wilcoxon test and Cox proportional hazard model.

Conclusion Our new strategy of dose escalation to high risk areas of extrapancreatic nerve plexus invasion at NACRT for PC has a favorable effect on locoregional control and potentially survival benefit. PO-0773 Radiomics Nomogram that Predicts for OS of patients diagnosed Esophageal Squamous Cell Cancer Z. Li 1 , C. Han 2 , Y. Yin 1 , L. Wang 2 , J. Zhu 1 , B. Li 1 1 Shandong Cancer Hospital affiliated to Shandong University, Department of Radiation Physics, Jinan, China 2 the Fourth Hospital of Hebei Medical University, Department of Radiation Oncology, shijiazhuang, China Purpose or Objective To develop a radiomics nomogram for exploring the prognostic value of diffusion weighted magnetic resonance imaging (DWI) in esophageal squamous cell carcinoma (ESCC) patients undergoing concurrent chemo- radiotherapy (CRT).