ESTRO 37 Abstract book

S785

ESTRO 37

EP-1442 Low-density lipoprotein promotes lymphatic metastasis of esophageal squamous cell carcinoma C. Liu 1 , H. Deng 1 , Y. Yin 1 1 Shandong Cancer Hospital Affiliated to Shandong University, Radiation oncology, Ji'nan, China Purpose or Objective The purpose of this study was to investigate the prognostic role of the preoperative serum lipid level in patients with esophageal squamous cell carcinoma (ESCC) and to explore the preliminary mechanism. Material and Methods Preoperative lipid levels, total cholesterol (TC), low- density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol and triglycerides (TG) were assessed in 242 ESCC patients. To eliminate the influence of nutritional status, all patients had undergone esophagectomy. Univariable and multivariable Cox regression analyses were performed to identify predictors of overall survival (OS). Associations between the significant lipid targets and clinical features were then analyzed, and the results were validated in TE-1 and ECa109 esophageal cancer cells. The cell proliferation level was measured with the CCK8 assay, and the cell cycle was assessed with PI staining and flow cytometry. Results In the univariable analysis, we found that HDL (p=0.048), LDL (p=0.020), pT status (p=0.001), pN status (p=0.001), and histological differentiation (p=0.002) were significantly associated with OS. In the multivariable analysis, LDL (hazard ratio (HR): 2.164, p=0.005), pT status (HR: 1.714, p=0.001), pN status (HR: 1.966, p=0.001) and histological differentiation (HR: 4.083, p=0.002) were risk factors in ESCC patients. A high LDL level (>3.12 mmol/L) indicated more susceptibility to lymphatic metastasis (p=0.004) and was associated with gender (p=0.001) and tumor location (p=0.007). The results of the CCK8 assay showed that LDL facilitated TE- 1 and ECa109 cell proliferation, and the flow cytometry analysis showed that treatment with LDL at an appropriate concentration resulted in an accumulation of cells in the G2 phase and decreased the number of cells in the G1 phase. Conclusion The preoperative LDL serum level plays an important role in predicting the disease outcome because LDL promotes lymphatic metastasis of ESCC. Furthermore, a preliminary mechanism has been validated in vitro. for neoadjuvant chemoradiotherapy in oesophagueal cancer. F. Lopez-Campos 1 , E. Carrasco 1 , C. De la Pinta 1 , M. Martín-Martín 1 , A. Hervás 1 1 Hospital Ramon y Cajal, Oncología Radioterápica, Madrid, Spain Purpose or Objective Neoadjuvant chemoradiotherapy according to the CROSS trial followed by surgical resection is regarded as a standard of care for patients with resectable locally advanced oesophageal or oesophagogastric junctional cancer. We report preliminary results of a prospective pilot study of a dose-escalated radiation therapy in patients treated with this scheme in order to evaluate tumour regression grade and toxicity. Material and Methods Patients with clinically resectable, locally advanced cancer of the oesophagus or oesophagogastric junction EP-1443 Dose-escalated radiation therapy

with new trials incorporating dose escalation. We conducted a systematic review of IGRT approaches in

oesophageal cancer. Material and Methods

A search of MEDLINE, Embase, Cochrane Library, Web of science and SCOPUS databases used the terms oesophageal cancer, image guided radiotherapy, IGRT, fiducial markers, 4 dimensional computed tomography and 4DCT . 927 articles were identified. These were then assessed for relevance by EM and SG. Articles published earlier than 2000 were excluded.

Results 4DCT

Movement of oesophageal tumour is greatest in the superior and inferior direction and greater in the distal oesophagus. Magnitude of motion can vary with T stage, with motion significantly smaller in T4 tumours. The optimal method of ITV creation would be delineation of target volumes on up to 10 phases of the respiratory cycle combined to form the ITV, but this is time consuming and other methods have been used, including the use of the maximum intensity projection and the use of smaller number of phases, with a visual check of the other phases to ensure full coverage. The latter is the recommended approach in the UK SCOPE 2 trial. In the absence of 4DCT data, anisotropic ITV margins in the region of 1.5cm in the superior inferior direction and 0.8cm circumferentially are recommended. 4DCT volumes are smaller than their corresponding 3DCT volumes, with resultant reduction in dose to OARs, shown in one study, to reduce V25Gy to the heart reduced by 6% and V20Gy to the lung by 3% when compared to 3DCT. Fiducials Insertion of fiducial markers can lead to improved tumour delineation and interfraction set up verification, both of which require stability and reproducibility of the fiducials. Interfractional visibility is 88-90% with flexible coil fiducials, compared to 11% with hydrogel fiducials. Flexible gold coil markers >5mm have good stability and visibility but radio-opaque hydrogel fiducials lead to poor visibility, likely due to tissue re-absorption of the gel. Insertion of fiducials can improve the identification of tumour length on planning CT scan, in comparison to endoscopic findings alone, , although this study was undertaken prior to the availability of PET, which is now widely used to assist in TVD . Conclusion Oesophageal movement is asymmetrical and patient- specific, individualised margins using 4DCT data are recommended. Delineation on 10 phases is time consuming and alternative methods have been proposed. In general 4DCT PTV volumes are lower than 3DCT and early data does suggest this will have a dosimetric advantage on doses to the organs at risk, which may allow further dose escalation. Fiducials are stable and reproducible and gold fiducials are recommended. The evaluation of CBCT data is ongoing and will be presented at the meeting.