ESTRO 37 Abstract book

S52

ESTRO 37

Results A total of 135 patients with esophageal cancer were included in this study. 3DCRT, IMRT and VMAT were used for neoadjuvant radiation dose delivery in 41 (30.4%), 60 (44.4%) and 34 (25.2%) patients, respectively. The three groups were comparable regarding baseline characteristics, expect for ASA score (p=.008) (Table 1). Dose distribution to the lungs varied significantly between the three modalities (Table 2). A total of 41 patients (30.4%) developed pneumonia following esophagectomy. In multivariable logistic regression analysis (adjusted for age, ASA score and pulmonary comorbidity), the risk of postoperative pneumonia was significantly lower in the IMRT and VMAT group compared to the 3D-CRT group (corresponding OR’s and 95%-CI’s: 0.30 (0.11–0.82, p=0.018) and 0.31 (0.10–0.99, p=0.049), respectively).

Material and Methods We analyzed data from 281 EC patients treated with preCRT followed by surgery at our institution between 2002-2016. The endpoints for analysis were postoperative pulmonary and cardiac complications, which were prospectively scored according to the international definition of Low et al (Ann Surg 2015). We assessed complications as a Comprehensive Complication Index (CCI) above 1750, or 300 in case of pleural effusions requiring prolonged chest drainage after surgery. For each individual radiotherapy plan, the lungs and heart were manually delineated according to the current algorithm and recalculated dose-volume histograms (DVH) were exported. Radiation dose varied between 36 Gy and 50.4 Gy, delivered in fractions of 1.8 Gy or 2 Gy. An univariable logistic regression analysis was performed to study the predictive value of lung and heart dosimetric variables (volumes receiving 5 Gy (V5) to 55 Gy (V55) and mean dose) for postoperative pulmonary and cardiac complications. The Area Under the Curve (AUC) of the receiver operating characteristic curve was calculated. Results Respectively 153 (54%) and 90 (32%) of the 281 patients developed pulmonary and cardiac complications. Normal- tissue complication probability modelling identified that the volume of the lung receiving 30 Gy (V30), 35 Gy (V35) and 40 Gy (V40) was statistically significantly associated with the risk of postoperative pulmonary complications (respectively AUC=0.59, 0.58 and 0.57; p=0.025, 0.025 and 0.033; Fig. 1). The volume of the lung receiving 5 Gy (V5) and 10 Gy (V10) was associated with postoperative cardiac complications (respectively AUC=0.56 and 0.59; p=0.047 and 0.015; Fig. 2). There was a trend to more cardiac complications with increasing mean lung dose (AUC=0.57; p=0.054). No cardiac dose volume parameter was correlated to neither cardiac nor pulmonary complications.

Table 1 Baseline characteristics

Table 2: Radiation dose to the lungs for the three modalities

Conclusion The risk of postoperative pneumonia following esophagectomy is significantly lower when neoadjuvant radiation dose is delivered using IMRT or VMAT, compared to 3D-CRT. These results can contribute to future refinement of the dose constraints for the lungs. PV-0100 Impact of lung dose on postoperative complications after trimodality treatment in esophageal cancer M. Thomas 1,2 , G. Defraene 1 , M. Lambrecht 1,2 , J. Moons 3 , P. Nafteux 3 , K. Haustermans 1,2 1 KU Leuven – University of Leuven, Oncology - Experimental Radiation Oncology, Leuven, Belgium 2 University Hospitals Leuven, Radiation Oncology, Leuven, Belgium 3 University Hospitals Leuven, Thoracic Surgery, Leuven, Belgium Purpose or Objective Preoperative chemoradiotherapy (preCRT) followed by surgery is considered standard of care in the treatment of locally advanced esophageal cancer (EC). The aim of this study was to investigate the effect of radiation dose on the risk of postoperative pulmonary and cardiac complications among EC patients treated with a trimodality approach.