| Esophageal carcinoma is the most common cancer in China, accounting for more than 50 percent of patients aroud the world. Mortality of esophageal carcinoma ranks the fourth place in malignant tumor in China. Radiotherapy has always been the main treatment methods because most of patients suffered from the locally advanced stage of this disease.Three-dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy(IMRT) are the novel approaches to the field of radiation therapy. But the delineation of the gross tumor volume and determination of clinical target volume were still to remain controversial; 3DCRT and IMRT techniques on esophageal carcinoma are also needed to be further studied due to lacking mature expericnce in China and on abroad.Firstly, this study aimed to evaluate the variance and the concordance with the neoplasm measured by CT scans and esophagogram and endoscopy vs tumor actual length, which might be helpful in delineating the length of gross tumor volume (GTV) of primary neoplasm. Secondly, in order to optimize the determination of the clinical target volume (CTV), we analyzed the incidence of a positive resection margin and influencing factors in 1162 surgical specimens for the patients with esophageal carcinoma. In the end, we evaluated the planning target volume (PTV) and organs at risk (OARs) dose distribution of 3DCRT and IMRT techniques for 10 patients with esophageal carcinoma, so as to recommend the optimization 3DCRT and IMRT plans for different location of esophageal carcinoma.Part I CT scans and esophagogram and endoscopy vs surgical specimens in the tumor length and GTV delineation in radiotherapy for the thoracic esophageal carcinoma Objective: To evaluate the variance and the concordance with the neoplasm measured by CT scans and esophagogram and endoscopy vs tumor actual length.Methods: Fifty-two surgical specimens were made into pathologic giant section. The actual length of tumor and the upper and the lower clearance margin were calculated by the specimen shrinkage ratio when fixed 24h by formalin. The length of esophageal neoplasm were measured by CT scans and esophagogram and endoscopy, then evaluated the variance and the concordance between the tumor length measured by these different methods and tumor actual length.Results:①The tumor tissue was shrink to 90±10% of their actual in situ length when 52 surgical specimens were made into pathologic giant section.②The mean length of the tumor measured by CT scans was longer than that of the actual tumor (5.8±2.4cm vs 4.1±1.8cm,P=0.000); CT scans examination was concordant with tumor actual length in 40.9%.③The mean length of the tumor measured by esophagogram was longer than that of the actual tumor (4.7±1.9cm vs 4.1±1.8cm , P=0.000); esophagogram examination was concordant with tumor actual length in 58.2%.④The mean length of the tumor measured by endoscopy was shorter than that of the actual tumor (3.5±1.5cm vs 3.9±1.8cm,P=0.000); endoscopy examination was concordant with tumor actual length in 70.0%.⑤74 patients with esophageal carcinoma were measured simultaneously by CT scans and esophagogram and endoscopy in all. The mean length of the primary tumor, being from short to long, were the endoscopy, tumor actual length, esophagogram and CT scans. Tumor length measured by endoscopy got mostly close to actual tumor length. The highest and the lowest concordance with actual tumor length were endoscopy and CT scans, respectively (P=0.001) .⑥Concordance with tumor length between CT scans and esophagogram was poor (P=0.032, Kappa=0.152) ; and neither CT scans or esophagogram were concordant with endoscopy in length of tumor.Conclusion:①Our study proved that obvious bias was existed between CT scans and tumor actual length.②Esophagogram and endoscopy presented a higher accuracy in establishing the tumor length, as compared to CT scans.③GTV delineation of the esophageal carcinoma should be refer to the combination of the esophagogram and endoscopy and CT scans results.Part II A study of a positive resection margin incidence and its influencing factors and CTV determination in radiotherapy for the thoracic esophageal carcinomaObjective: To analyze the incidence of a positive resection margin and influencing factors so as to help define the CTV for radiotherapy for esophageal carcinoma.Methods We examined 1162 resected esophageal carcinoma specimens originally located in the neck and thorax between positive resection margin and influencing factors, such as upper and lower resection clearance margin and lymph node metastasis, etc. The actual resection length of upper and lower para- esophageal normal tissues correlated with higher positive resection margin were calculated by the specimen shrinkage ratio when fixed 24h by formalin.Result:①The actual length of upper and lower normal esophageal tissue after having been made into pathological giant sections in 52 patients, were 30±14% and 44±19% of that measured in the operation.②After fixation, microscopic positive margin ratio in length≤0.5cm group was higher than that in length >0.5cm group for the upper resection border (16.4 vs 4.1%, P= 0.000); considering the shrinkage of the normal esophagus during fixation, the actual length of upper resection border with higher microscopic positive margin was 1.7cm.③Microscopic positive margin ratio in length≤1.5cm group was higher than that in length >1.5cm group for the lower resection border (8.1 vs 0.4%, P= 0.000); considering the shrinkage of the normal esophagus during fixation, the actual length of lower resection border with higher microscopic positive margin was 3.4cm.④The upper resected border microscopic positive margin ratio was 7.5% and 4.1% in N1 and N0 stage , respectively; the lower resected border microscopic positive margin ratio was 1.5% and 0.3% in N1 and N0 stage of patients, respectively; microscopic positive margin ratio was higher in N1 stage of patients than that in N0 stage of patients.⑥The upper microscopic positive margin ratio was obviously higher than the lower microscopic positive margin ratio (8.1 vs 0.4%, P= 0.000).Conclusion:①The normal tissue length of para-esophageal resection border and the lymph node metastasis were the main influencing factors of microscopic positive resection margin.②A recommended CTV margin of 2.0cm along the upper long axis and 3.5cm along the lower long axis should be chosen for radiotherapy for esophageal carcinoma considering the shrinkage of the normal esophagus during fixation, .Part III Comparison of conformal and intensity-modulated techniques for thoracic esophageal carcinomaObjective: To evaluate optimized 3DCRT and IMRT plans for different location of esophageal carcinoma.Methods: Ten patients with thoracic esophageal carcinoma underwent CT simulation, then GTV was defined as any visible tumor on the CT image and refer to the esophagogram and endoscopy simultaneously, CTV and PTV were also defined as the same criteria. The minimum prescription dose received by the 95% PTV was 6000 cGy. Dosimetry of the PTV and OARs delivered by different 3DCRT and IMRT plans were compared by dose-volume histogram and TCP and NTCP so as to recommend the optimization plans for different location of esophageal carcinoma.Result:①For the upper esophageal carcinoma, dose distribution for the PTV was similar among the 3DCRT plans (P>0.05); 4F CRT plan reduced lung V20 as compared to 6F CRT plan (P<0.05), mean lung dose of 3F and 6F CRT plans were higher than that of 4F CRT plan (P<0.05).②For the middle esophageal carcinoma, PTV D95 and PTV V100 of the 4F and 6F CRT plans were lower than that of 3F CRT plan (P<0.05); lung V20 of 6F CRT plan was higher than that of 3F and 4F CRT plans (P<0.05).③For the lower esophageal carcinoma, PTV V115 and V100 of the 4F CRT plan were higher than that of 4F CRT plan (P<0.05); lung V20 of 6F CRT plan was higher than that of 3F and 4F CRT plans (P<0.05).④For the upper esophageal carcinoma, PTV D100 of the 3F IMRT plan was lower than that of 9F and 11F IMRT plans(P<0.05); PTV V110 of the 9F IMRT plan was lower than that of 3F and 4F and 5F IMRT plans(P<0.05); PTV V110 of the 7F IMRT plans was lower than that of 4F IMRT plan(P<0.05); dose of the OARs received was similar among the IMRT plans (P>0.05).⑤For the middle esophageal carcinoma, PTV D100 of the 3F IMRT and S-IMRT plans was lower than that of 7F and 9F IMRT plans(P<0.05); PTV V110 of the 7F and 9F and 11F IMRT plans were lower than that of S-IMRT plan(P<0.05); PTV V110 of the 9F IMRT plan was lower than that of 3F and 4F and 5F IMRT plans(P<0.05); PTV V110 of the 7F IMRT plan was lower than that of 4F IMRT plan(P<0.05); dose of the OARs received was similar among the IMRT plans (P>0.05).⑥For the lower esophageal carcinoma, PTV D100 of the 3F IMRT was lower than that of any IMRT plans excluding 3F IMRT plan(P<0.05); PTV V110 of the 9F and 11F plans was lower than that of 3F and S-IMRT plans(P<0.05); dose of the OARs received was similar among the IMRT plans (P>0.05).⑦For the upper esophageal carcinoma, PTV CI of 4F CRT plan was lower than that of 5F and 7F IMRT plans. PTV HI of 4F CRT plan was higher than that of 5F and 7F IMRT plans. PTV D100 and D95 and V100 and V95 of the 4F CRT plan were all lower than that of 5F and 7F IMRT plans(P<0.05); 7F IMRT plan reduced lung V20 as compared to 4F CRT plan (P<0.05).⑧For the middle esophageal carcinoma, dose distribution between 3F CRT plan and 5F and 7F IMRT plans were superior to each other; lung V5 and V10 and V20 and V30 and MLD and NTCP of the 3F CRT plan were all higher than that of 5F and 7F IMRT plans(P<0.05); mean dose of the heart of 3F CRT plan was lower than that of 7F IMRT plan.⑨For the lower esophageal carcinoma, dose distribution between 4F CRT plan and 5F and 7F IMRT plans were superior to each other; lung V10 of the 4F CRT plan was higher than that of 4F and 5F and 7F IMRT plans(P<0.05); lung V20 of the 4F CRT plan was higher than that of 5F and 7F IMRT plans (P<0.05); MLD of the 4F CRT plan was higher than that of 4F and 7F IMRT plans (P<0.05); mean dose of the heart of 4F CRT plan was lower than that of 7F IMRT plan (P<0.05).⑩For the upper esophageal carcinoma, PTV dose distribution of S-IMRT plan was superior than that of 4F CRT plan, lung V20 of 4F CRT plan was higher than that of S-IMRT plan. For the middle and lower esophageal carcinoma, S-IMRT plan was superior than CRT plan as compared to protecting the lung and CRT plan was superior than S-IMRT plan as compared to protecting the heart.Conclusion:①4F CRT plan should be recommend for the upper and lower esophageal carcinoma, and 3F CRT plan should be recommend for the middle esophageal carcinoma.②5F and 7F IMRT plans should be recommend for the upper and middle esophageal carcinoma; and 4F and 5F and 7F IMRT plans should be recommend for the lower esophageal carcinoma.③5F and 7F IMRT plans were better than 4F CRT plan for upper esophageal carcinoma; and IMRT plans recommend for the middle and lower esophageal carcinoma were superior to protecting the lung tissues; and CRT plans recommend for the middle and lower esophageal carcinoma were superior to protecting the heart tissues.
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