Correlation between GTV-T Volume, Clinical Stage and Prognosis of Esophageal Carcinoma Patients Treated with Three-dimensional Conformal Radiotherapy

Objective To evaluate the accuracy and coincidence degree of clinical stage of esophageal carcinoma and to assess the prognosis by applying the size of tumor volume. Methods We retrospectively analyzed the clinical data of 375 patients with esophageal carcinoma treated by radical three-dimensional conformal radiotherapy(3DCRT). GTV-T stage was carried out to these patients as classification standard of clinical T stage of esophageal carcinoma. We proposed the clinical stage of these patients combining with lymph node metastasis, furthermore, we evaluated the accuracy of the classification standard referring to the prognosis of these patients. Results Corresponding to pathological stage T, GTV-T volume were classified into 4 levels, T1, T2, T3 and T4, according to ≤30 cm³, 30-≤60 cm³, 60-90 cm³ and＞90 cm³. According to survival curves of patients, there was no significant difference between stage T3 and T4(P=0.556), while GTV-T volume were classified into 3 levels according to T1, T2 and T3+4, there was significant difference among each group(P＜0.001). Stage N0 esophageal carcinoma patients without regional lymph nodes had a better prognosis than stage N1-2 ones with or without regional lymph nodes(P=0.000). Clinical stage of esophageal carcinoma was divided into stageⅠ, ⅡandⅢ according to stage T1, T2 and T3+4 of GTV-T volume. The patients with stage N2 or distant metastasis were classified as stage Ⅳ. There was significant difference among each stage(P＜0.001). Conclusion GTV-T volume is a good prognosis factor according to three-classification by stage T1, T2 and T3+4. In responding to GTV-T three-classification, clinical fourclassification could also reflect prognosis well.