Proposed revision of CT-based cervical and thoracic lymph node levels for esophageal cancer in UICC 7th version

Background and purpose: To propose revisions of CT-based cervical and thoracic lymph node levels for esophageal cancer in UICC 7th version.

Material and methods: One hundred and forty-nine patients who underwent surgery were analyzed retrospectively for hypothesis validation, 338 patients who underwent definitive radiotherapy to evaluate the feasibility in clinical work, and 121 patients from another independent cohort for external evaluation. We redefined Level VI in the RTOG consensus guideline of CT-based cervical lymph node levels, and established a new Level 1 in the IASLC guideline of CT-based thoracic lymph node levels. We also shrunk Level 3p. Lymph nodes were assigned into different levels by three criteria.

Results: We encountered stratification problems in 63 patients by JSED criteria and in 24 patients by RTOG criteria. Multivariate analysis showed that nodal status was independently associated with OS in the three cohorts (p<0.001). No significant difference was found between the Level 1 only group and the mediastinal nodes only group (p>0.05).

Conclusions: The proposed hypothesis clearly defined the boundary area between the cervical and thoracic parts, brought more convenience for stratification, better predicted patients' OS and provided information for both pre-treatment evaluation and multidisciplinary treatment planning.