Station 7 metastasis in upper lobe non-small cell lung cancer ≤2 cm: anatomical anomaly or marker of tumor aggressiveness?

We read with great interest the study by Pan et al., which provides a valuable, large-scale analysis of lymph node (LN) metastasis patterns in non-small cell lung cancer (NSCLC) ≤2 cm (1). The authors’ work offers a strong foundation for personalizing surgical management. Their proposal for lobe-specific dissection and the identification of a subset of upper lobe tumors—those measuring ≥1 cm with a pure solid appearance that may benefit from subcarinal (station 7) dissection is a pertinent step toward reducing surgical invasiveness. However, this specific recommendation, based on observations in 5 patients, presents a critical opportunity to refine the rationale for surgical decision-making. The fundamental question remains whether this pattern reflects inevitable anatomical drainage or select tumor biology, a distinction with immediate consequences for patient care.

The recommendation to dissect station 7 for qualifying upper lobe tumors is premised on a pragmatic observation but lacks a mechanistic explanation. If metastasis to station 7 is primarily driven by fixed anatomical lymphatic pathways, such as direct drainage or unpredictable anastomoses, then the recommendation stands as a necessary, non-selective procedural adaptation for all tumors meeting the size and radiology criteria. This would represent a modification of the lobe-specific map based on an anatomical exception. Conversely, if this pattern is fueled by inherent tumor aggressiveness, then the policy could be further individualized. In this scenario, biological markers of aggression, potentially already present in the authors’ dataset, might identify which specific tumors within this subgroup truly warrant extended dissection, sparing others the additional procedure. This ambiguity touches upon a broader surgical philosophy: are we tailoring operations based on where the tumor is, or based on what the tumor is? The authors’ data present a unique chance to investigate this intersection.

Clarifying this mechanism is not an academic exercise but has direct implications for evolving clinical practice. The field is moving beyond anatomical extent alone, integrating biological factors to define surgical aggression. For instance, the presence of lymphatic vessel invasion (LVI) or a high Ki-67 proliferation index is an established marker of aggressive disease and metastatic potential in NSCLC (2,3). Recent investigations confirm that such biomarkers can predict occult nodal disease and worse prognosis even in early-stage tumors (4,5). If the five index cases exhibited pronounced features of biological aggression—such as elevated Ki-67, LVI, or poor differentiation—compared to upper lobe tumors without station 7 spread, it would strongly suggest that the observed metastasis is a marker of a particularly aggressive tumor phenotype, not a universal anatomical fate. This would align with emerging concepts in precision oncology, where treatment intensity is matched to tumor biology.

Therefore, to transform this observation from a geographical rule into a biologically informed guideline, we propose the following analytical steps that leverage the authors’ existing cohort without requiring new experimental work. First, a comparative analysis of the five index cases against other upper lobe pure solid tumors ≥1 cm that did not involve station 7 should be conducted. Key variables already collected, including Ki-67 index, presence of lymphovascular invasion, pleural invasion, and histologic differentiation, can be compared. A pronounced difference in these aggressive features would support the “tumor aggressiveness” hypothesis. Second, the authors could perform a focused multivariate analysis within the subgroup of upper lobe pure solid tumors ≥1 cm. This model would assess whether factors like Ki-67 index or LVI are independently associated with station 7 metastasis, potentially offering a more precise predictive tool than radiological appearance alone. Third, to explore the anatomical hypothesis, a detailed review of imaging for the five cases could assess tumor proximity to the oblique or horizontal fissure. Some studies suggest tumors near fissures may have aberrant drainage to station 7 (6). If a consistent anatomical relationship is found, it would strengthen the “anatomical anomaly” argument.

Addressing this question will significantly enhance the impact of the authors’ important findings. By determining whether station 7 involvement in this subset is a matter of anatomical destiny or biological selection, the authors can provide a more nuanced, robust framework for surgical planning. It could lead to a stratified recommendation: perhaps only aggressive upper lobe tumors require routine station 7 inspection, or maybe all tumors in a specific anatomical sub-location do. Either answer, derived from their robust dataset, would advance the goal of truly precise and personalized lymphadenectomy, ensuring the proper dissection is performed for the right tumor biology in the correct anatomical context.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was a standard submission to the journal. The article did not undergo external peer review.

Funding: This work was supported by the Project of Sichuan Provincial Department of Science and Technology: Research on Constructing a Benign and Malignant Prediction Model for Subsolid Pulmonary Nodules Based on Multi-omics Application Machine Learning (No. 2024NSFSC0733).

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2026-1-0323/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

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References

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