Microscopic Extention Analysis From 1162 Esophageal Carcinoma Specimens

To examine the subclinical microscopic tumor extention along the long axis in 1162 specimens of esophageal carcinoma so as to help define the clinical target volume (CTV) according to the degree of microscopic extention(ME) for radiotherapy of esophageal carcinoma. Fifty-two resected esophageal carcinoma specimens were made into pathological giant sections. Measurements of upper and lower resection margins from the primary tumor were made in situ at operation before the esophagus were removed. Specimens were fixed by formalin, and the shrinkage ratio of the upper and lower normal tissues from the primary tumor was established. Then we studied 1162 resected esophageal carcinoma specimens originally located in neck and thorax. Based on the length after being fixed, specimens were divided into 7 groups with an increment of 0.5cm to analyze the correlation between upper and lower resection length from the primary tumor and positive microscopic margin. Groups that were not significantly different after paired comparison were combined together. So clinical target volume(CTV) along the esophagus long axis of the 1162 esophageal carcinomas could be calculated by the shrinkage ratio formerly established. The actual length of upper and lower normal esophageal tissue after having been made into pathological giant sections in 52 patients was 30±14% and 44±19% of that measured in the operation. For the 1162 esophageal carcinoma specimens(fixed), microscopic positive margin ratio of the upper resection border in length ≤0.5cm group was higher (p =0.000)than that in length>0.5cm group (16.4%, 18/110) vs 4.1% (43/1052). Microscopic positive margin ratio of the lower resection border in length ≤1.5cm group was higher (p =0.000) than that in length>1.5cm group (8.1%, 3/37) vs 0.4% (5/1125). Positive margin ratio of the upper border was higher (p = 0.000) than that of the lower border in resection length>1.5cm group (3.5%, 25/724) vs 0.4% (5/1125). Considering the shrinkage of the normal esophagus after the fixation, a CTV margin of 2.0cm along the upper long axis and 3.5cm along the lower long axis should be chosen as radiation area in radiotherapy for esophageal carcinoma. In esophageal carcinoma, ascending invasion is more common than the descending invasion.