Understanding the pattern of lymph node metastasis for trans-segmental thoracic esophageal cancer to develop precise delineation of clinical target volume for radiotherapy.

Abstract

This study was conducted to explore the lymph node metastasis (LNM) pattern of thoracic esophageal cancer (TEC) depending upon the location of the primary tumor and provide a reference for the design of clinical target volume (CTV). The data of patients who underwent radical esophagectomy and three-field lymph node dissection at Fujian Cancer Hospital from 2006 to 2010 were retrospectively analyzed. We segmented the esophagus according to the anatomical landmarks on computed tomography (CT) and defined the transsegmental and mono-segmental esophageal carcinoma. The LNM pattern in trans-segmental and monosegmental esophageal cancer was explored and the CTV delineation was determined based on LNM pattern. A total of 852 patients were included in this study. The top five sites of LNM for upper-middle TEC were cervical, upper and middle paraesophageal, and zone 1, 2, 4 regions. The most common sites of LNM for lower-middle TEC were cervical and middle paraesophageal, group 3, 7, and zone 7 regions. The top five sites of LNM for middle-upper TEC were cervical, middle paraesophageal, zone 1, 7, and group 7 regions. The most common sites of LNM for middle-lower TEC were cervical, middle paraesophageal, zone 7, and group 2, 7 regions. The top five sites of LNM for TEC involving all the segments were cervical, middle paraesophageal, zone 7, group 2 and 7 regions. LNM pattern of trans-segmental and mono-segmental TEC varies depending upon the primary tumor location. The irradiation field must be designed according to the primary tumor location.