Abstract
The aim of this study was to quantify the radiation dose to the corresponding lymph drainage area in esophageal cancer using three-dimensional conformal radiation therapy (3D-CRT) with involvED-field IRradiation (IFI) and to analyze associated factors. A retrospective analysis oF 81 patients with esophageal cancer was conducted. According to the location of the lesions, the lymph drainage area was delineated and the dosimetric parameters were calculated. The 1-, 3-, 5- and 8-year survival rates of the patients were 67.90, 33.33, 20.99 and 11.11%, respectively. Based on the dose-volume histogram in the treatment plan, we calculated the volume percentage of the planning target volume including clinically positive lymph nodes (PTV-N) receiving radiation doses of 30, 35, 40, 45 and 50 Gy (V(PTV-N30-50)). The median values of V(PTV-N30-50) were 73, 70, 67, 64 and 58%, respectively. The prescribed dose size exhibited no correlation with V(PTV-N30-35), but did exhibit a significant correlation with V(PTV-N40-50); the radiation field was not correlated with V(PTV-N30-45), but exhibited a significant correlation with V(PTV-N50); The length of the lesion on esophageal barium meal X-ray and the PTV were significantly correlated with V(PTV-N30-50). The analysis of variance revealed that the V(PTV-NX) value in the upper thoracic segment was higher compared with that in the middle and lower thoracic segments; V(PTV-N30-35) values differed significantly according to the different locations of the lesions, whereas V(PTV-N40-50) values exhibited no significant differences. The value of V(PTV-NX) exerted no significant effect on long-term patient survival. Therefore, the corresponding lymph drainage area of esophageal cancer IS subjected to a certain Radiation dose when patients undergo 3D-CRT with IFI, which may play a role in the prevention of regional nodal metastasis. However, this hypothesis requires confirmation by further clinical studies.