The relationship between the dose-volume indexes and acute toxicity of intrathoracic stomach in esophageal cancer patients receiving radiotherapy after esophagectomy

Objective To study the relationship between the dose-volume indexes and acute toxicity of intrathoracic stomach in esophageal cancer patients receiving radiotherapy after esophagectomy. Methods A total of 104 patients treated with postoperative radiotherapy followed by radical esophagectomy were enrolled. The dose-volume indexes of intrathoracic stomach were collected from treatment planning system. The ROC curve and logistic regression were performed to analyze the relationship between acute toxicity of intrathoracic stomach and clinical parameters, dose-volume indexes. Results A total of 29 patients (27.88 %) suffered from grade 2 or above acute toxicity. The ROC curve analysis showed that the dose-volume indexes including Dmax, Dmean, L5-L45 and V5-V50were associated with occurrence of grade 2 or above acute toxicity. The univariate analysis showed that location, Dmax, Dmean, L5-L45 and V5-V50 were significantly correlated with the incidence of grade 2 or above acute toxicity (P 14.00 cm and 38.64% for L5≥14.00 cm (χ2=4.473, P<0.05), 14.08% for V35<44.00% and 57.58% for V35≥44.00% (χ2=7.263, P<0.05), respectively. The incidence of grade 2 or above acute toxicity was significantly higher in post-mediastinum stomach group than the other two groups (χ2=12.881, P<0.05). Conclusions Dose-volume index may be indicator to predict acute toxicity of intrathoracic stomach. It is recommended that post-mediastinum stomach should be chosen carefully if esophageal cancer patients require postoperative radiotherapy. Key words: Esophageal carcinoma; Operation; Intrathoracic stomach irradiation injury; Dose-volume indexes