Avoiding locoregional relapse after segmentectomy: radiologic aggressiveness, margin discipline, and technical precision

Segmentectomy has moved from a compromise procedure to a standard option for selected early-stage non-small cell lung cancer (NSCLC), supported by randomized evidence such as JCOG0802/WJOG4607L (1). As indications expand, locoregional control remains the central vulnerability of parenchyma-sparing surgery.

In an ad hoc supplementary analysis of JCOG0802/WJOG4607L, Nakagawa and colleagues focused on locoregional relapse (LR) after segmentectomy. Among 1,105 randomized patients (segmentectomy 529; lobectomy 576), LR occurred more frequently after segmentectomy than after lobectomy (8.9% vs. 6.9%). In multivariable analysis within the segmentectomy cohort, pure-solid appearance on thin-section computed tomography (CT), margin distance less than tumor size, and male sex were significantly associated with LR; lingular segment tumors also showed a higher LR tendency than left upper division tumors (2).

Two practical implications emerge from these findings. First, radiologic phenotype matters, pure-solid tumors may represent a higher-risk subgroup when segmentectomy is being considered. Second, margin discipline matters, and it becomes particularly important when biology is unfavorable. The finding that margin distance less than tumor size was associated with LR supports evaluating margin feasibility preoperatively that encourages teams to treat margin feasibility as a preoperative endpoint rather than a postoperative audit item (2). A post-hoc analysis focusing specifically on radiologically pure-solid tumors within the same trial framework further highlighted the clinical trade-off: segmentectomy may improve overall survival (OS), yet it can increase locoregional recurrence, and effect modification by age and sex warrants careful interpretation when counselling patients and selecting procedures (3).

External randomized data similarly emphasize that sublobar resection can be oncologically appropriate in strictly selected peripheral stage IA disease, but oncologic safety depends on disciplined execution and adequate nodal assessment (4). Therefore, the key contemporary question is not whether segmentectomy can be performed, but whether a given segmentectomy can reliably achieve sufficient margins and appropriate nodal evaluation in that specific anatomic setting. In addition to these trial-derived observations, institution-specific retrospective studies may offer complementary, hypothesis-generating perspectives that help refine patient selection and operative planning in selected clinical settings.

Positron emission tomography (PET)/CT hypermetabolism as an additional caution signal

Many teams incorporate PET/CT to refine selection. In a propensity score-matched analysis from the authors’ group of clinical stage IA “hypermetabolic” tumors [maximum standardized uptake value (SUVmax) ≥3.0], sublobar resection was associated with worse overall and disease-free survival than lobectomy, supporting the concept that high SUVmax can function as a practical warning sign when considering parenchyma-sparing resection (5). Although SUV thresholds are not perfectly standardized across platforms. Marked PET/CT hypermetabolism may serve as a contextual caution signal when parenchyma-sparing resection is being considered particularly when margin feasibility is borderline. Because SUV values are influenced by scanner calibration, acquisition protocols, reconstruction methods, and institutional practice, SUVmax ≥3.0 should not be interpreted as a universal cutoff. Rather, PET/CT findings may be interpreted together with CT phenotype, tumor location, and anticipated margin feasibility.

Centrally located lesions: “technically feasible” is not the same as “oncologically safe”

As segmentectomy indications expand, centrally located tumors warrant careful evaluation. A retrospective analysis from the authors’ group suggested that centrally located clinical stage I NSCLC tends to be more hypermetabolic and demonstrates a higher frequency of lymph node metastasis than peripherally located tumors. The investigators concluded that centrally located disease may require greater caution when sublobar resection is considered (6). In such settings, the concern is not only tumor biology but also whether segmentectomy can provide sufficiently comprehensive hilar nodal evaluation. The risk-benefit balance becomes more fragile when centrality, pure-solid phenotype, and PET/CT hypermetabolism coexist. Figure 1 summarizes the overall workflow, whereas Table 1 provides phase-specific checkpoints and escalation triggers to operationalize the same concepts.

Figure 1 Implementation workflow to reduce locoregional relapse after segmentectomy. 3D, three-dimensional; CT, computed tomography; PET, positron emission tomography; SUVmax, maximum standardized uptake value.

Margin-first workflow: planning, execution, verification

To translate “margin intent” into achieved margins, teams benefit from a reproducible roadmap. Evidence from wedge resection cohorts supports the principle that greater margin distance is associated with lower recurrence risk and longer survival, reinforcing the need to plan margins proactively rather than retrospectively (7). At the authors’ institution, three-dimensional CT reconstruction is routinely used for segmentectomy planning with particular attention to intersegmental veins as anatomic landmarks. A vein-first strategy guided by three-dimensional (3D)-CT can simplify progression to deeply located bronchovascular structures and reduce disorientation during complex segmentectomy, thereby improving the likelihood that the planned margin can be delivered (8). Intraoperatively, surgeons visually inspect the resected specimen in the operative field to confirm that the gross margin is acceptable. If it appears borderline, they consider extending the resection (Table 1). However, in stapled segmentectomy, pathological margin measurement does not always reproduce the true in vivo spatial relationship between the tumor and the intended parenchymal resection line, because tissue compression and deformation occur along the staple line. In addition, although frozen-section assessment is generally reliable for bronchial margins, it is rarely feasible for stapled intersegmental parenchymal planes. Accordingly, surgical margin intent and pathological margin confirmation should be viewed as related but not always equivalent concepts. Although radiologic factors such as C/T ratio may help stratify risk, R0 resection and margin integrity remain central determinants of locoregional control after segmentectomy. Margin adequacy may also be influenced in part by device-related tissue compression and deformation, and ongoing technical developments in stapling technology may have future relevance for margin preservation. Accurate identification of the target segmental bronchus is a prerequisite for oncologic segmentectomy, particularly in complex resections with deep hilar structures and anatomic variations (9). Misidentification can lead to an unintended resection plan and, ultimately, jeopardize margin intent. An additional practical point is that margin planning has intrinsic limitations when based on conventional axial CT alone. Segmentectomy is a geometric operation constrained by patient-specific bronchovascular anatomy, and three-dimensional CT reconstruction can therefore be valuable to assess margin feasibility before committing to a parenchyma-sparing plan. From an oncologic perspective, LR is a composite endpoint that may reflect distinct mechanisms (e.g., recurrence related to the resection margin or intersegmental plane versus relapse in regional nodal stations). Reporting pattern-specific LR (margin-related vs. nodal), together with the extent and quality of nodal evaluation during segmentectomy, would further strengthen the surgical interpretability of the current findings.

Platform (robotic vs. thoracoscopic): prioritize reproducibility in a minimally invasive era

Determinants of LR emphasized in the trial-derived analyses—radiologic phenotype and margin adequacy—are unlikely to be platform-specific (2,3). In the current minimally invasive era, teams should select the platform “thoracoscopic or robotic” that best supports consistent anatomic identification, safe vessel control, and disciplined nodal evaluation in their environment, without compromising oncologic safeguards.

Limitations and future directions: integrating pathology beyond CT and margins

The supplementary analysis is post hoc, and event numbers limit power for site-specific inference. In addition, key pathologic variables were not systematically captured during the JCOG0802/WJOG4607L trial period, because spread through air space (STAS) had not yet been widely recognized as a distinct invasion pattern at the time of trial conduct. The investigators acknowledge that detailed pathology—particularly STAS—may be important for understanding local relapse after sublobar resection, and they plan further analyses using centrally collected resection specimens to clarify the association between STAS (and related pathologic features) and clinical outcomes; although STAS cannot be reliably diagnosed preoperatively in routine practice, this uncertainty further supports a cautious margin-first strategy in radiologically aggressive tumors (2,10,11).

In conclusion, trial-derived supplemental analyses provide a practical risk framework indicating that pure-solid appearance and insufficient margins are key determinants of LR after segmentectomy, while the pure-solid post-hoc analysis highlights the need to communicate the OS-LR trade-off transparently (2,3). Integrating CT phenotype, PET/CT metabolic signals, careful consideration of centrality, and a standardized margin-first workflow with 3D-CT-based planning—and avoiding bronchial misidentification—may help preserve the functional advantages of segmentectomy while minimizing LR risk (2,3,5-11).

Acknowledgments

We are grateful to Takayuki Sasage, MD; Kazumasa Hoshijima, MD; Kohei Abe, MD; for their assistance and critical feedback. They provided permission to be acknowledged and received no financial compensation.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Shanghai Chest. The article has undergone external peer review.

Peer Review File: Available at https://shc.amegroups.com/article/view/10.21037/shc-2026-1-0006/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://shc.amegroups.com/article/view/10.21037/shc-2026-1-0006/coif). J.S. serves as an unpaid editorial board member of Shanghai Chest from August 2025 to July 2027. The other 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.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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