ABSTRACT
Objective To compare the dosimetric difference among TomoDirect (TD) radiotherapy,Helical Tomotherapy(HT) and volumetric modulated arc therapy(VMAT) in the treatment of upper thoracic esophageal carcinoma.Methods A total of 15 patients with cT2-4 N0-1 M0 upper thoracic esophageal squamous cell carcinoma were enrolled.Three plans were generated using the same dose objective for each patient:TD,HT and VMAT.Dose-volume histogram (DVH),homogeneity index (HI),conformal index (CI),dose at organ at risk (OAR),delivery time and monitor unit (MU) were compared among different plans.Results The D2 and D values in the HT and TD plans were significantly lower than those in the VMAT plans.The D98 value in the TD was similar to that in the HT,but lower than that in the VMAT.The HI of HT was significantly better than those of TD and VMAT (F =81.603,P ＜ 0.05).For the CI,there was no significant difference among the three techniques (P ＞ 0.05).For the V15 of lung,HT was significantly higher than TD (t =-2.626,P ＜0.05) and VMAT (t=3.547,P ＜ 0.05).The V20 of lung in TD was similar to that in HT,but higher than that in VMAT (t =2.824,3.052,P ＜ 0.05).The Dmax of spinal cord showed no significant difference among the three techniques.VMAT had a significantly shorter delivery time and lower MU compared with HT and TD (t =21.617,15.693,10.018,7.802,P ＜ 0.05).Conclusions HT and TD could gain a better planning target volume (PTV) coverage and HI than VMAT in the treatment of upper thoracic esophageal carcinoma.However,VMAT achieved the lowest lung V20,the least Mus and the shortest delivery time.HT achieved a better PTV coverage compared with TD,but TD had a lower lung V15 Mus and shorter delivery time compared with HT.
ABSTRACT
Objective To study the effect of three dimensional conformal intensity modulated radiotherapy and prognostic factors for postoperative local recurrent esophageal squamous cell carcinomas.Methods A total of 468 patieuts with postoperative local recurrent esophageal squamous cell carcinomas were retrospectively analyzed.The median interval between surgery and recurrence was 14.95 months (2-252 months).There were 45 patients with supraclavicular lympy node relapse,291 with mediastinal lymph node relapse,4 with abdominal lymph node relapse,15 with anastomosis relapse,89 with supraclavicular and mediastinal lymph node relapse,11 with anastomosis and mediastinal lymph node relapse,7 with mediastinal and abdominal lymph node relapse,1 with supraclavicular and anastomosis relapse,2 with supraclavicular and abdominal lymph node relapse,3 with anastomosis,mediastinal and supraclavicular lymph node relapse.There were 224 patients who received three-dimensional conformal radiation therapy,and the other 244 patients of intensity-modulated radiation therapy,with a median dose of 59.4 Gy (40-70 Gy).A total of 166 patients received adjuvant chemotherapy.Kaplan-Meier method was used to calculate the survival rate;Log-rank test was used for univariate prognostic analysis;Cox regression test was used for multivariate prognostic analysis.Results The follow-up rate was 95.3％.The recent curative effect in the effective rate was 81.6％,with 41.2％ CR rate.The overall 1,2,3,4 years of survival rates after radiotherapy were 61％,32％,21％,14％ respectively and the median survival time was 17.6 months.Univariate analysis showed that age,.pathologic stage,the number of positive lymph node cleaning,the recurrence area,single or multiple lesions,the size of the lesion,overall response rate,radiation dose,and chemotherapy (x2 =4.814-247.322,P ＜ 0.05) were associated with prognosis.Multivariate analysis showed that age,pathologic stage,the recurrence area,single or multiple lesions,the size of the lesion,overall response rate,radiation dose,and chemotherapy (P ＜0.05) were independent prognostic factors.A total of 370 patients had progressive diseases after radiotherapy,176 had local failure 47.57％ (176/370),148 had distant metastasis 40.00％ (148/370) and 16 had both local and distant failures 4.32％ (16/370).One case died of pneumonia;2 cases died of acute myocardial infarction;1 case died of cerebral hemorrhage;26 cases died of unknown cause (including lost to follow-up).Lung was the most common distant metastatic site.Conclusions Radiotherapy may improve the survival of esophageal squamous cell carcinoma patients with postoperative recurrence.Patients with less than 70 years old,early postoperative stage,single recurrent lesion,initial small lesions,response to radiotherapy,radiation dose of higher than 59.4 Gy,chemoradiation might have better prognosis.