ESTRO 38 Abstract book

S416 ESTRO 38

study aimed to identify whether lung dosimetric parameters were predictive for severe lymphopenia in esophageal cancer patients. Material and Methods A total 117 patients with esophageal cancer underwent neoadjuvant chemoradiotherapy followed by surgery during 2010 and 2015 in two academic centers were analyzed. With majority male gander, current smoker, squamous cell carcinoma histology, and clinical stage III disease, all patient underwent neoadjuvant therapy consisted of 2-3 course of cisplatin and 5-fluorouracil concurrent with radiotherapy (median dose 44 Gy). Patients with severe lymphopenia, defined as absolute lymphocyte count ≤ 500 during neoadjuvant therapy were compared to those without this toxicity. The logistic regression was used to identify predictive treatment- related and dosimetric factors for severe lymphopenia. Factors with a p value <0.05 were considered significant. Further receiver-operating characteristic (ROC) curve was performed for theses dosimetric parameters to obtain best cutoff values. Results The mean heart dose of all patients was 18.06 Gy [standard deviation (SD): 6.67Gy]. The mean lung volume receiving 5 Gy or more (V5), lung V10, and lung V20 was 72.8% (SD: 21.1%), 52.2% (SD:17.8%), 20.3% (SD:6.5%), respectively. Lung V5 (odds radio [OR]: 1.03, 95% confident interval [CI]: 1.00-1.06, p = 0.04) and ECOG performance status (0 vs. 1, OR: 3.30, 95% CI: 1.15-9.44, p = 0.03) were associated with severe lymphopenia when adjusting for pre-treatment feeding jejunostomy, cisplatin intensity, gross tumour volume, gross tumour dose, and lung V10. The ROC curve analysis generated best cutoff value of lung V5 of 75% (the area under the curve: 0.75, p <0.001). High probability of severe lymphopenia in patients with lung V5≥75% compared to those with lung V5<75% (55.74% vs. 16.07%, p < 0.001). Conclusion Higher lung V5 was associated with severe lymphocyte declined in esophageal cancer patients underwent neoadjuvant chemoradiotherapy followed by surgery. Constraints for low dose lung volume may avoid severe lymphopenia in these patients. PO-0803 Endoluminal brachytherapy with induction chemotherapy and definitive chemoradiation in Ca.Esophagus S. Raghunath 1 , R. Tiwari 1 , G. Narayanan 1 , B. Vishwanathan 1 , R. Sultana 1 1 Vydehi Institute of Medical Sciences and Research Center, Radiation Oncology, Bangalore, India Patients in remote areas in Rural India, South Asia, Africa and Poorer EU Member States do not have access to surgical infrastructure or qualified personnel to deliver high quality surgery in locally advanced esophageal carcinoma. Further, Esophageal Cancer has an abysmal response despite multimodality treatment. Endoluminal Brachytherapy is an under-utilized modality in the curative setting and an elegant tool to escalate the dose to improve the clinical response and clinical symptoms. This study examines if Dose Escalation with Endoluminal Brachytherapy after Induction Chemotherapy and Definitive Chemoradiation is feasible in the background of the above scenarios in underserved populations. Objective: To evaluate Dysphagia Free Interval (DFI), Disease Free Survival (DFS), Overall Survival (OS) and Toxicity Profile in Purpose or Objective Need for the Study: Over 75% of people with cancer worldwide have no access to safe surgery. Access is worse in low income countries where 95% of people with cancer do not receive basic cancer surgery.

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Conclusion Both in ADK and SCC we achieved a good local control (>85%). There was no significant differences in OS between treatments. We showed that ADK were mostly treated with NRTC and SCC with RTC illustrating the difficulties of NRTC on SCC. Worth noticing, the OS of SCC treated with RTC demonstrated an OS as good as surgical series despite the advanced tumor stage of those patients (> 50% stage III) and tobacco / alcohol related co- morbidities. These results, good tumor local controlled and OS for locally advanced tumors questioned the place of surgery as a standard of treatment for SCC. PO-0802 Lung dose was associated with severe lymphopenia in esophageal cancer undergoing trimodality therapy J. Lin 1 , J. Lee 2 , C. Cheng 3 , T. Chang 4 , Y. Chen 2 1 Changhua Christian Hospital, Radiation Oncology, Changhua, Taiwan ; 2 MacKay Memorial Hospital, Department of Radiation Oncology, Taipei, Taiwan ; 3 Changhua Christian Hospital, Department of Thoracic Surgery, Changhua, Taiwan ; 4 Changhua Christian Hospital, Department of Radiation Oncology, Changhua, Taiwan Purpose or Objective Previous studies had reported lymphopenia was associated with poorer outcomes in esophageal cancer. The lung was reservoir of hematological stem cell. Radiotherapy and chemotherapy might destroy the hematological stem cells in the lung and could contribute to lymphopenia. This