Topography of the sentinel node according to the affected lobe in lung cancer

Abstract

Purpose: The objective of this study is to describe the anatomic location of the sentinel lymph node (SLN) of patients with lung carcinoma and to analyze its relationship with the characteristics of the tumor.

Patients and methods: 98 Stage I lung cancer patients were included in the study. SLN was marked just after performing the thoracotomy by injecting peritumorally 0.25 mCi of nanocolloid of albumin (Nanocol1) labeled with Tc-99 m in 0.3 ml, and later, it was resected. For SLN micrometastasis analysis, CEACAM5, BPIFA1, and CK7 gene expression at mRNA level was studied. Possible relation between tumor characteristics and SLN location was analyzed.

Results: While most of the SLN were located in hilar area, we find a significantly higher number of SLN located in mediastinal stations when the lesion is in the left upper lobe (LUL). This difference disappears in the group of SLN with a positive result in the micrometastasis study. Regarding tumor size, squamous tumors and tumors located in the left lower lobe (LLL) were found significantly larger.

Conclusion: The location of the SLN in patients with stage I lung cancer is predominantly hilar, being less consistent in the left hemithorax. The tumor size or histological type is not variables that affect this distribution. The distribution of SLNs with a positive result in the analysis of micrometastasis suggests further spread to the hilar areas when the lesion is in the LUL and to the mediastinal zones when it is in the LLL.

Keywords: Lung cancer; Nodal station; Sentinel lymph node; Tumor anatomical location.