Pathological analysis of extracapsular extension of metastatic lymph node and its potential impact on nodal clinical target volume in the radiotherapy of esophageal squamous cell carcinoma

Abstract

There is no consensus regarding the clinical target volume (CTV) margins which surround the gross tumor volume of metastatic lymph nodes (LN) in radiotherapy of esophageal squamous cell carcinoma (ESCC). This study retrospectively assessed the distance of extracapsular extension (ECE) of metastatic LN in thoracic ESCC and defined nodal CTV margins. Histological sections of metastatic LNs from 217 patients with thoracic ESCC were re-examined. The incidence and maximal distance of ECE of metastatic LNs were assessed. The relationships between ECE and clinicopathologic features were also investigated. The ECE was found in 37.3% of patients (81/217) and 23.1% of metastatic LN (159/689), and the incidences had a significant relationship with N stage and LN size. The median distance of ECE was 1.0 mm (range, 0.2-9.7 mm). The distance of ECE showed a positive correlation with LN size (Spearman's correlation coefficient = 0.419; p<0.001). The ECE distances of LN with <10 mm diameter were significantly smaller than LN with 10-30 mm diameter (p<0.001). The 95th percentiles of ECE distances for these two groups were 3 mm and 5 mm, respectively. For pathologic LN <10 mm in diameter, a 3-mm CTV margin appears to be adequate to encompass 95% of the microscopic ECE, and for LN 10-30 mm, a 5-mm CTV margin is recommended.

Influence of negative lymph node in No 7 on survival of patients with middle thoracic esophageal squamous cell carcinoma

“… 9 , 10 It refers to the pathological positive area of LN which is considered as being closely related to the outcome of patients. 11 – 13 But there is still controversy about which LN stations should be included in treatment planning. 14 – 17 The LN stations of 101, 104-R, 105, 106rec-L, 106tb-L, 106tb-R, 107, 108, 110, 112, 2, 3, and 7 are generally considered as high-risk regions and are commonly included in treatment planning in thoracic ESCC.…”

The Key Clinical Questions of Neoadjuvant Chemoradiotherapy for Resectable Esophageal Cancer—A Review

“…Wang et al. ( 23 ) assessed 217 individuals with ESCC, and proposed a margin of 3.0–5.0 mm from GTVn to CTVn in order to include 95% of the extracapsular extension of lymph node, which depends on the diameter of the lymph node. CTVn provided a 0.5- to 1.0-cm radial margin around the GTVn to include the area of subclinical involvement in the NEOCRTEC5010 trial ( 5 ).…”

Proposal for the delineation of neoadjuvant target volumes in oesophageal cancer

“…Table S2) [27]. Wang et al evaluated 217 patients with a squamous cell carcinoma, and suggested a margin of 0.3-0.5 cm from GTVn to CTVn to encompass 95% of the extracapsular extension, depending on the diameter of the lymph node [28].…”