Room: Davidson Ballroom B
Purpose: To correlate dosimetric dose-volume parameters with the incidence of esophagitis for lung cancer patients.
Methods: The hypothesis is that the acute esophagitis was related to the dose-volume parameters, which could be dosimetric predictors of acute esophagitis. In this retrospective single institution study, the treatment charts of 243 lung cancer patients treated from year 2014 to 2017 were reviewed. Mean esophagus dose (MED), dose volume parameters Vx (percentage esophageal volume receiving â‰¥ x Gy), and the endpoints of esophagitis grade 1 and 2 based on Radiation Therapy Oncology Group definitions were derived from the Pinnacle treatment planning system and the EPIC electronic medical record system, respectively. Binary logistic regression and probit statistical analysis were used to determine the relationship between the probability of grade 1 and 2 esophagitis with MED and Vx. The statistical analyses were performed using IBM SPSS V24 at the 5% significant level (Î±=0.05).
Results: Vx (V5, V10, V15, V20, V30, V40, V50 and V60) and MED are associated with probability of the incidence of esophagitis grade 1 and 2, which increased with increasing the values of Vx and MED. V20, V30, V40, and V50 are statistically significant good dosimetric predictors of radiation induced esophagitis grade 1. The MED associated with a 50% incidence probability (TD50) for grade 1 and 2 esophagitis was determined as 1,510 cGy and 4,594 cGy, respectively. The parameters of Lyman Kutcher Burman model, n, m and TD50, were fitted and compared with other published findings.
Conclusion: The results suggest that MED, V20, V30, V40, and V50 are good predictors of the radiation-induced esophagitis. TD50 of grade 1 and 2 esophagitis were determined using the predictive model established in this study. Our findings may be useful as additional clinical guidelines for treatment planning and plan evaluation, as well as obtaining informed patient consent.