ESTRO 37 Abstract book

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ESTRO 37

6 UMC Utrecht, Department of Surgery, Utrecht, The Netherlands 7 The University of Texas MD Anderson Cancer Center, Department of Thoracic and Cardiovascular Surgery, Houston, USA 8 The University of Texas MD Anderson Cancer Center, Department of Radiation Oncology, Houston, USA Purpose or Objective Patients with esophageal cancer who suffer from early disease progression after completing trimodality therapy (TMT; chemoradiation plus surgery) may be better served by alternative treatment strategies. The aim of this study was to develop a preoperative risk prediction model for 1-year progression free survival (PFS) after TMT for esophageal cancer, and assess the survival benefit of subsequent surgery in low-risk and high-risk patients, respectively Material and Methods In total 568 consecutive patients with potentially resectable esophageal adenocarcinoma who underwent TMT (n= 373) or bimodality therapy (BMT; definitive chemoradiotherapy; n=195) between 2006 and 2015 were included. A nomogram for 1-year PFS after TMT was created using Cox’s regression model and performance was assessed by discrimination and calibration after internal validation. Patients were stratified into risk groups based on predicted 1-year PFS. Overall 5-year survival was compared between TMT and BMT in low-risk and high-risk patients after propensity score matching, respectively. Results Of 373 patients who underwent TMT, 102 (28%) had disease progression within the first year following esophagectomy. The final prognostic model for 1-year PFS included male gender, poor histologic grade, signet ring cell adenocarcinoma, cN1, cN2-3, and baseline SUV max , with accurate calibration and reasonable discrimination (optimism-adjusted C-statistic: 0.66). TMT was associated with a significantly higher overall survival compared to BMT in the low-risk group ( p =0.003), whereas it showed no significant survival benefit in the high-risk group ( p =0.302).

Conclusion The proposed nomogram predicts 1-year PFS after TMT for esophageal cancer and may aid in individualized treatment decision-making before esophagectomy. External validation is warranted. PV-0099 Neoadjuvant radiation dose to the lungs and the risk of postoperative pneumonia in esophageal cancer A.S. Borggreve 1 , P.S.N. Van Rossum 2 , R. Van Hillegersberg 3 , J.P. Ruurda 3 , S. Mook 2 1 UMC Utrecht, Radiation Oncology and Surgical Oncology, Utrecht, The Netherlands 2 UMC Utrecht, Radiation Oncology, Utrecht, The Netherlands 3 UMC Utrecht, Surgical Oncology, Utrecht, The Netherland Purpose or Objective Neoadjuvant chemoradiation followed by surgical resection is the cornerstone of curative treatment for locally advanced, resectable esophageal cancer. The radiation dose distribution on the surrounding vital organs depends on clinical characteristics such as tumor location, tumor length, N-status, as well as on the radiation modality used (e.g. 3D-CRT, IMRT, VMAT). Neoadjuvant radiation dose has already been associated with several postoperative complications, such as anastomotic leakage, cardiac complications and wound infections. Another frequently observed complication is postoperative pneumonia (up to 39%). It was hypothesized that a larger volume of the lungs that receives radiation dose, potentially influences the risk of postoperative pneumonia in esophageal cancer patients. The aim of the current study was to investigate whether radiation dose delivery with 3D-CRT, IMRT or VMAT during neoadjuvant chemoradiotherapy in esophageal cancer patients affects the risk of postoperative pneumonia. Material and Methods Patients with esophageal cancer who underwent neoadjuvant chemoradiotherapy according to the CROSS regimen followed by a transthoracic esophagectomy in our tertiary referral center were included. Baseline variables such as age, sex, ASA score, comorbidity and histopathology, as well as the outcome postoperative pneumonia were prospectively acquired. Pneumonia was defined according to the Uniform Pneumonia Score (UPS). Three commonly used radiation modalities with varying dose distributions to the lungs were compared, namely 3D-CRT, IMRT or VMAT. Baseline characteristics, radiation technique and the risk of postoperative pneumonia were analyzed using uni- and multivariable logistic regression analysis.