Occult N1 upstaging in non-small cell lung cancer: why lobectomy still matters

A recent study conducted by Mohammad Abdallat and colleagues, “Segmentectomy vs Lobectomy for Occult N1 in Non-Small Cell Lung Cancer: Is Less More?” (1), revisits one of thoracic oncology’s most enduring dilemmas: how should surgeons respond when unsuspected nodal metastasis is discovered intraoperatively in a patient scheduled for sublobar resection?

Historical context: sublobar resection vs. lobectomy

The controversy surrounding the extent of resection in early-stage non-small cell lung cancer (NSCLC) has been defined for decades by the balance between oncologic safety and preservation of lung parenchyma. The landmark CALGB 140503 and JCOG0802/WJOG4607L trials provided much-needed clarity, demonstrating that anatomical segmentectomy is non-inferior to lobectomy in terms of survival for small (≤2 cm), peripherally located, clinically node-negative (cN0) tumors (2,3).

However, both trials were designed to avoid the uncertainty of nodal involvement: patients with suspicious or confirmed nodal disease were excluded. This left a clinically important gap, since even with meticulous preoperative staging—including positron emission tomography-computed tomography (PET-CT) and invasive mediastinal sampling—between 6% and 18% of patients with presumed stage IA disease are ultimately found to harbor pathological N1 metastases at resection.

Historically, the discovery of occult N1 disease during a segmentectomy has led surgeons to perform a completion lobectomy, based on the assumption that a larger parenchymal resection would ensure more complete oncologic clearance. However, this practice is largely based on surgical dogma rather than solid evidence. Moreover, reoperation for completion lobectomy following segmentectomy in cases of postoperative nodal upstaging is not routinely recommended (4).

Abdallat’s contribution: equivalent survival in the Occult N1 setting

Abdallat et al. sought to address this evidence gap by analyzing a single-institution cohort of 185 patients treated between 2006 and 2023 who were upstaged to pN1. Of these, 30 underwent segmentectomy and 155 lobectomy. As expected, the lobectomy cohort was composed of patients with larger tumors and greater metabolic activity on PET, reflecting both surgical selection and tumor biology.

To minimize confounding, the authors used propensity-score weighting and adjusted for age, lymphovascular invasion, and tumor size. Although lobectomies showed a significantly higher number of positive lymph nodes and were associated with an increased risk of death and recurrence in this study, the number of positive lymph nodes was not included among the variables used to construct the propensity score, which may be worth considering when interpreting the adjusted comparisons. The analysis showed no statistically significant differences in overall survival (OS) or locoregional recurrence-free survival between the two groups. The 5-year adjusted OS was 68.4% for segmentectomy and 57.2% for lobectomy, and procedure type did not emerge as an independent predictor of prognosis.

This finding challenges the long-held belief that completion lobectomy is necessary once occult nodal disease is detected and suggests that the survival benefit of resecting additional lung parenchyma may be limited in this context.

Supporting evidence and the recurrence paradox

Abdallat’s results are consistent with prior analyses from national databases and multicenter series. These studies converge on the conclusion that lobectomy does not confer a survival advantage over segmentectomy in patients upstaged to nodal disease.

However, any discussion of parenchymal preservation must address concerns regarding local control. A recurring observation is that local recurrence tends to be more frequent following segmentectomy. One multicenter study documented local recurrence in 35.5% of patients after segmentectomy versus 21.4% after lobectomy. Similarly, a large registry analysis reported higher recurrence rates and inferior disease-free survival with segmentectomy, although these differences did not translate into worse OS.

This “recurrence paradox” underscores a key reality: the prognosis of node-positive NSCLC is determined less by local control than by systemic disease dynamics. The greater threat lies not in the residual ipsilateral lobe but in the potential for distant metastases, which is effectively reduced by adjuvant chemotherapy. Nevertheless, the potential risk of a higher rate of local recurrence cannot be overlooked, as it may directly affect patients’ quality of life.

Clinical implications: a nuanced approach

These insights have direct consequences for surgical decision-making:

• Routine completion lobectomy may not be warranted. For carefully selected patients—particularly those with tumors ≤2 cm and peripheral location—segmentectomy appears to provide survival outcomes equivalent to lobectomy. Preserving lung parenchyma is not a trivial benefit: it helps maintain pulmonary reserve, reduces perioperative morbidity, and preserves options for future resections if second primary tumors develop which are frequent in this population.
• Systemic therapy is the cornerstone. In Abdallat’s series, receipt of adjuvant therapy was independently associated with improved survival [hazard ratio (HR) 0.379, P<0.001]. These findings suggest that once nodal disease is confirmed, patient outcomes hinge far more on the timely delivery of adjuvant chemotherapy than on whether a segmentectomy or lobectomy was performed. Accurate and up-to-date nodal staging is essential to avoid missing a clinical N1 stage, which should now benefit from neoadjuvant chemoimmunotherapy.

Tumor size remains a decisive factor. The weight of evidence supports segmentectomy for tumors ≤2 cm, but favors lobectomy for tumors measuring 2–3 cm (cT1c/pT1c), where several meta-analyses demonstrate superior survival with lobar resection (5,6). In a meta-analysis, lobectomy was associated with better long term outcomes than sublobar resection (7). The inclusion by Abdallat et al. of only patients with tumors smaller than 2 cm in the lobectomy group would have been more consistent with current guidelines, rather than using a propensity score based on tumor size.

Refining risk stratification is essential. Beyond nodal status, other pathological features such as spread through air spaces (STAS) and higher T stage are strongly predictive of recurrence and survival (8). Incorporating these markers into surgical algorithms may be more meaningful than applying a uniform resection strategy. Notably, STAS was not systematically reported until later in Abdallat’s cohort, which limits interpretation of its impact.

Perspectives: toward precision surgery and multimodal therapies

The study by Abdallat and colleagues contributes to a growing body of evidence suggesting that the oncologic value of completion lobectomy for occult N1 NSCLC is limited, even though segmentectomy has been associated with higher rates of local recurrence in larger series. For selected patients, segmentectomy—when coupled with effective systemic therapy—provides equivalent long-term survival while preserving lung function.

The path forward is not simply about choosing between lobectomy and segmentectomy, but about tailoring multimodal strategy to tumor biology. The next generation of studies must integrate detailed histopathological and molecular profiling into surgical decision-making. Prospective registries and randomized trials designed to account for tumor behavior—not merely size and nodal status—will be critical to defining which patients can safely undergo segmentectomy (9).

Beyond the debate on the extent of parenchymal resection, the evolving landscape of perioperative systemic therapy further reshapes the discussion. Robust evidence now supports neoadjuvant chemoimmunotherapy for node-positive and locally advanced NSCLC, with randomized trials such as CheckMate 816 (10) demonstrating substantial improvements in pathological complete response and OS compared with chemotherapy alone. Similar benefits have been observed in the NADIM II trial with major pathological response rates exceeding 50% in stage III disease (11).

Actually, current recommendations from the National Comprehensive Cancer Network now prioritize neoadjuvant chemoimmunotherapy for tumors ≥4 cm or node-positive disease. But there is some interest and challenges in neoadjuvant for early-stage NSCLC (12).

In this way, “less” surgery may truly become “more”—not through dogma or necessity, but through precision, multimodal and individualized care.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Current Challenges in Thoracic Surgery. The article has undergone external peer review.

Peer Review File: Available at https://ccts.amegroups.com/article/view/10.21037/ccts-2025-1-65/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://ccts.amegroups.com/article/view/10.21037/ccts-2025-1-65/coif). The authors have no conflicts of interest to declare.

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