Comparative outcomes of lobectomy and combined segmentectomy in left upper-lobe lung cancer: a propensity score-matched analysis

Introduction

Background

Recent advances in the surgical treatment of early-stage lung cancer have triggered debate regarding the optimal extent of resection. Historically, lobectomy is the gold standard for radical resection, providing a balance between oncologic efficacy and lung function preservation (1). However, advances in high-resolution imaging diagnostics for early tumor detection and improvements in surgical techniques have led to an increasing number of sublobar resections—such as segmentectomy and wedge resection—being performed for smaller, earlier-stage lung cancers.

Rationale and knowledge gap

Recent studies have demonstrated that segmentectomy for peripheral small-cell lung cancer is non-inferior to lobectomy in terms of overall survival (OS) (2). Furthermore, sublobar resection (segmentectomy and wedge resection) has been shown to be non-inferior to lobectomy in disease-free survival (3). However, these sublobar resections remain limited to small tumors in peripheral areas, such as those <2 cm (2). Segmentectomy has been reported to offer advantages such as preservation of respiratory function and reduction of postoperative complications (4-6). On the other hand, it has been reported to cause significantly more locoregional recurrences compared to lobectomy, and some studies suggest that shorter resection margins are associated with a higher incidence of locoregional recurrence (7). Therefore, the indications for segmentectomy must be carefully evaluated. Currently, there are situations where lobectomy is preferable even for small tumors, while conversely, there are cases where segmentectomy must be chosen even for large tumors.

The left upper lobe is one of the largest lobes in the lungs and is divided into two anatomical units: the upper division (segments 1+2 and segment 3) and the lingula (segments 4 and 5). The anatomical classification is similar to that used for the right upper and middle lobes. We considered combined segmentectomy, such as tri-segmentectomy and lingulectomy for left upper lobe lung cancer, to be a segmentectomy closer to lobectomy among segmentectomies. Therefore, we hypothesized that combined segmentectomy (tri-segmentectomy and lingulectomy) for left upper-lobe lung cancer would provide comparable oncologic outcomes to lobectomy, potentially increasing the indications for segmentectomy.

Objective

This study aimed to explore the potential for expanding the indications for segmentectomy in patients with left upper lobe lung cancer. We compared the oncological outcomes of lobectomy and combined segmentectomy in patients with left upper lobe lung cancer, including cases exceeding the current criteria for segmentectomy. We used propensity score matching (PSM) to adjust for patient background and compared long-term outcomes. Some subgroup analyses were conducted, targeting cases without clinically detectable lymph node metastases or cases exceeding the current criteria for segmentectomy. Furthermore, we conducted a focused analysis on recurrence, particularly locoregional recurrence. We present this study in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1-2568/rc).

Methods

Patient grouping

This retrospective study was approved by the ethics committees of Hokkaido University Hospital (approval No. 024-0417) and Sapporo Minami-Sanjo Hospital (approval No. R6-6). This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The requirement for informed consent was waived due to the retrospective nature of the study. We screened 255 patients consecutively who underwent left upper lobectomy or combined segmentectomy (tri-segmentectomy or lingulectomy) at Hokkaido University Hospital and Sapporo Minami-Sanjo Hospital between January 2012 and December 2017. Eight patients were excluded from this study. We excluded patients who underwent neoadjuvant chemotherapy, preoperative radiation therapy, and those whose pathological stage was M1 (n=8). Finally, 247 patients were included. Patients were divided into two groups: the lobectomy group (L group, n=191) and the combined segmentectomy group (S group, n=56) (Figure 1). This study performed two subgroup analyses. The first subgroup analysis included patients with a consolidation-to-tumor ratio (CTR) >0.5 and tumor diameter >2 cm. The second subgroup analysis included cases that were clinically N0 and showed no evidence of interstitial pneumonia in the surrounding lung. Neither subgroup analysis was performed using PSM.

Figure 1 Flowchart depicting the selection of the study cohort. We included 191 patients in the left upper lobectomy group (L group) and 56 patients in the combined segmentectomy group (S group). A total of 247 patients were enrolled in this study. Fifty-three pairs of patients were included after propensity score matching. cN, clinical N category; C/T, a consolidation-to-tumor ratio; N, node; pM1, patients with pM1 disease; SUV, standardized uptake value.

Surgical procedure

The choice of surgical procedure (upper lobectomy or combined segmentectomy) and the extent of lymph node dissection was made at each hospital using a comprehensive assessment of the location, size, tumor characteristics, and patient’s condition. The surgical approach, either video-assisted thoracoscopic surgery or open thoracotomy, was selected based on the tumor location and condition. Choices regarding surgical procedure, approaches, and the extent of lymph node dissection were left to the discretion of each institution, and no unified standards had been established across facilities. Mediastinal lymph node dissection (MLND) was defined as follows: systematic lymph node dissection (ND2a-2) involving dissection of both upper and lower mediastinal lymph nodes, and selective lymph node dissection (ND2a-1) involving dissection of the upper mediastinal lymph nodes only. Lymph node sampling alone was classified under the no lymph node dissection category.

Data collection and definitions

Patient data were obtained from the multicenter database of Hokkaido University and the affiliated hospitals. They include demographic information, smoking status, pulmonary function tests, tumor characteristics (size, location, histology), surgical details (type of resection, operative time, blood loss), and postoperative outcomes (complications). Postoperative complications, such as lung fistula, included those that persisted for >7 days postoperatively and those that required possible surgical interventions. The clinical staging was based on the findings of computed tomography (CT), brain magnetic resonance imaging, and positron-emission tomography CT (PET-CT), and it was performed following the eighth edition of The Union for International Cancer Control (8). The CTR was defined as the ratio of the maximal solid part diameter to the maximal tumor diameter, including the area of ground-glass opacity; it was calculated for all patients from their CT images (9). The pathological staging of lung cancer was performed according to the seventh edition of The Union for International Cancer Control (10). Furthermore, patients were followed up every 3–6 months and underwent CT scans at least twice a year. The patients who had undergone postoperative follow-up at other hospitals were contacted by letter or telephone for follow-up. The observation period was 5 years postoperatively. We compared the 5-year OS, 5-year recurrence-free survival (RFS), and the 5-year cumulative incidence function (CIF) of locoregional recurrence between the L and the S groups. Locoregional recurrence was defined as the recurrence in the hilar and mediastinal lymph nodes, pleural effusion, pleura within the same lung lobe, and resection margins, such as staple lines and bronchotomy margins. Distant recurrence was defined as recurrence in the contralateral thoracic cavity or outside the thoracic cavity, including the contralateral lung field, pleural effusion, and pleura, brain, bones, adrenal glands, liver, supraclavicular nodes, pericardium, pericardial fluid, and others.

Statistical analysis

All statistical analyses were conducted using JMP^® software (Pro 17.0, SAS Institute Inc., Cary, NC, USA) and EZR (version 1.62, Saitama Medical Center, Jichi Medical University, Saitama, Japan). Continuous variables are presented as medians and interquartile ranges, with nominal variables shown as numbers and percentages. The Mann-Whitney U test was used to compare non-normally distributed continuous variables, whereas Fisher’s exact test was applied to categorical variables. The Kaplan-Meier method, alongside the log-rank test, was used to compare OS and RFS curves between groups. Cumulative incidence curves were used to evaluate disease survival time until locoregional recurrence, and the Gray test was applied to compare differences. Distant recurrence and mortality were calculated as competing risk events. All P values were two-sided, and statistical significance was set at P<0.05. Propensity score was computed using a logistic regression model, which incorporated eight baseline characteristics [age, sex, smoking history, tumor location (upper division or lingula), maximum tumor diameter, CTR, the maximal value of standardized uptake value (SUVmax) of the primary tumor, and clinical N stage]. The baseline characteristics included preoperative factors that were generally considered to affect prognosis and for which accurate information could be collected. PSM was performed on a 1:1 ratio using the nearest neighbor method, with a caliper value set at 0.2. Multivariable Cox regression analysis was performed on cases after PSM to identify prognostic factors for OS and to evaluate whether the surgical procedure influenced prognosis. The results were displayed in a forest plot.

Results

The characteristics of patients before and after PSM are shown in Table 1, and perioperative and postoperative outcomes are shown in Table 2. Age, sex, smoking history, and history of other malignancies were proportional between both groups before PSM. Preoperative respiratory function showed better forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) in the L group. The L group presented with notably larger tumors, higher SUVmax and CTR values, and more advanced clinical and pathological tumor (cT and pT) staging. No significant difference was observed in operation time and amount of blood loss between the two groups. Complications, including arrhythmia and recurrent nerve paralysis, were more common in the L group, whereas lung fistula was more common in the S group; however, there was no difference in the overall complication incidence rate. In the L group, MLND was more prevalent, and pathological nodal (pN) status showed greater advancement. The type of tumor histopathology and the rates of adjuvant chemotherapy induction were distributed equally across both groups.

In the analysis of all cases before PSM, the 5-year OS rates were closely matched, at 87.0% and 88.8% for the L and S group, respectively, with no significant difference observed (P=0.57) (Figure 2A). The 5-year RFS rate was better in the S group than in the L group (72.6% and 86.2% for the L and S groups, respectively, P=0.055) (Figure 2B). Although no statistically significant difference was observed for CIF of locoregional recurrence, the results for the S group were lower compared to those of the L group (7.08% and 2.01% for the L and S groups, respectively, P=0.15) (Figure 2C).

Figure 2 Comparison of long-term outcomes before and after propensity score matching. (A) Kaplan-Meier curve for 5-year OS before propensity score matching. The OS was 87.0% and 88.8% in the L and S groups, respectively (P=0.57). (B) Kaplan-Meier curve for 5-year RFS before propensity score matching. The RFS was 72.6% and 86.2% in the L and S groups (P=0.055). (C) Cumulative incidence curve of locoregional recurrence before propensity score matching. The CIF was 7.08% and 2.01% in the L and S groups (P=0.15). (D) Kaplan-Meier curve for 5-year OS after propensity score matching. The OS was 93.7% and 87.9% in the L and S groups, respectively (P=0.44). (E) Kaplan-Meier curve for 5-year RFS after propensity score matching. The RFS was 85.6% in the L group. (F) Cumulative incidence curve of locoregional recurrence after propensity score matching. The CIF was 0% and 4.10% in the L and S groups (P=0.15). L group: the lobectomy group. S group: the combined segmentectomy group. CIF, cumulative incidence function; OS, overall survival; RFS, recurrence-free survival.

A total of 53 patients from each group were accurately paired after PSM, eliminating the previously significant differences in tumor size, CTR, SUVmax, and cT. In addition, this alignment neutralized the disparities in pT and pN. The proportion of MLND was higher in the L group than in the S group after PSM. Post-PSM analysis demonstrated that the 5-year OS rates, 93.7% and 87.9% in the L and S groups, respectively, were similar in both groups (P=0.44) (Figure 2D). The 5-year RFS rates, 85.6% and 85.3% for the L and S groups, respectively, confirmed this trend (P=0.93) (Figure 2E). The CIF of locoregional recurrence was low in both groups, and no significant difference was observed between the L and S groups (0% and 4.10% for the L and S groups, respectively, P=0.15 (Figure 2F).

At 5 years postoperatively, 40 (20.9%) and 6 (10.7%) patients in the L and S groups, respectively, experienced recurrences (Table 3). A total of 12 cases were locoregional, and 26 showed distant metastases within the L group. In contrast, in the S group, two cases were local, and four showed distant metastases. There was no difference in the locoregional and distant recurrence rates between both groups. Furthermore, there was no recurrence at the resection margins in either group. After PSM, only two cases (3.80%) of locoregional recurrence occurred in the S group.

The results of the multivariable analysis for OS after PSM are shown in Figure 3. SUVmax was identified as an independent prognostic factor (hazard ratio: 1.19; 95% confidence interval: 1.05–1.37; P<0.01). Age, sex, tumor maximum diameter, CTR, and surgical procedure (lobectomy or combined segmentectomy) were not statistically significant.

Figure 3 Multivariate analysis with forest plots of prognostic factors according to 5-year overall survival after propensity score matching. L group: the lobectomy group. S group: the combined segmentectomy group. CI, confidence interval; CTR, consolidation-to-tumor ratio; HR, hazard ratio; SUV, standardized uptake value.

In the subgroup analysis of patients with a CTR >0.5 and tumor diameters >2 cm, comprising 128 patients in the L group and 23 in the S group, the Kaplan-Meier curve showed similar trends in the 5-year OS [82.6% and 76.0% in the L and S groups, respectively (P=0.85)] (Figure 4A). Similarly, the 5-year RFS rates in the L and S groups (62.8% and 77.0%) showed comparable outcomes (P=0.30) (Figure 4B). Regarding the CIF of locoregional recurrence, it was 8.24% in the L group and 4.55% in the S group, and no statistically significant difference was observed (P=0.52) (Figure 4C).

Figure 4 Comparison of long-term outcomes in cases with a CTR >0.5 and tumor diameters ≥2 cm. (A) Kaplan-Meier curves for 5-year OS in patients with a CTR >0.5 and tumor diameters ≥2 cm. The OS was 82.6% and 76.0% in the L and S groups (P=0.85). (B) Kaplan-Meier curves for 5-year RFS in patients with a CTR >0.5 and tumor diameters ≥2 cm. The RFS was 62.8% and 77.0% in the L group and S group (P=0.30). (C) Cumulative incidence curve of locoregional recurrence in patients with a CTR >0.5 and tumor diameters ≥2 cm. The CIF of locoregional recurrence was 8.24% and 4.55% in the L and S groups (P=0.52). (D) Kaplan-Meier curves for 5-year OS in patients with cN0 and no interstitial pneumonia. The OS was 89.8% and 91.3% in the L and S groups (P=0.80). (E) Kaplan-Meier curves for 5-year RFS in patients with cN0 and no interstitial pneumonia. The RFS was 75.4% and 87.8% in the L group and S group (P=0.09). (F) Cumulative incidence curve of locoregional recurrence in patients with cN0 and no interstitial pneumonia. The CIF of locoregional recurrence was 6.19% and 2.09% in the L and S groups (P=0.23). L group: the lobectomy group. S group: the combined segmentectomy group. CIF, cumulative incidence function; cN0, clinically negative lymph nodes; CTR, consolidation-to-tumor ratio; OS, overall survival; RFS, recurrence-free survival.

In the subgroup analysis of cases with clinically negative lymph nodes (cN0) and no interstitial pneumonia, no significant difference was observed in OS and RFS. The OS rates were similar between the two groups, at 89.8% in the L group and 91.3% in the S group (P=0.80) (Figure 4D). The RFS rates were 75.4% and 87.8%, respectively (P=0.09) (Figure 4E). Furthermore, the CIF of locoregional recurrence was 6.19% in the L group and 2.09% in the S group, with no significant difference between the two groups (P=0.23) (Figure 4F).

Discussion

Key findings

Our retrospective analysis addressed the debate over whether lobectomy or combined segmentectomy is preferable for treating lung cancer, particularly left upper-lobe lung disease. Building on findings from the Japan Clinical Oncology Group (JCOG), we examined how segmentectomy, a surgical option that preserves more lung tissue compared to lobectomy, affects 5-year OS, RFS rates, and locoregional recurrence. Based on our findings, combined segmentectomy may be one of the surgical treatment options for patients with left upper lobe lung cancer exceeding the current criteria for segmentectomy.

A notable finding of our investigation was the absence of significant differences in OS and RFS after matching. Before matching, it was unclear whether segmentectomy improved prognosis, as the L group included more advanced cases. During matching, predominantly early-stage patients from the L group were selected, allowing comparison between groups with similar disease stages. From both the matched analysis and the Cox proportional hazards model, surgical procedure (lobectomy or combined segmentectomy) did not appear to significantly impact prognosis in early-stage left upper-lobe lung cancer.

Subgroup analyses focused on a narrower group of patients. The subgroup analysis focusing on patients with tumors >2 cm in diameter and a CTR >0.5 targeted more advanced cases than the current indications for segmentectomy, based on the JCOG conclusions. Although this analysis has limitations in its power due to the small sample size in the S group (n=23), it suggests that combined segmentectomy holds potential as a treatment option even in patients with more advanced disease. In another subgroup analysis, we focused on cN0 cases without interstitial pneumonia and examined their prognosis as a patient group resembling the current indications for segmentectomy. When lymph node metastasis is clinically confirmed, or in patients with interstitial pneumonia, this alone significantly limits treatment options and is highly likely to have a major impact on prognosis. In the subgroup analysis excluding these cases, no difference in long-term prognosis was observed between lobectomy and combined segmentectomy, consistent with previous studies and supporting existing reports. Furthermore, regarding locoregional recurrence—a key concern in segmentectomy—no significant difference in locoregional recurrence rates was observed between the two groups in any analysis. Although tumor location and resection margins could not be evaluated in this study, the findings suggest the potential oncological safety of combined segmentectomy for left upper lobe lung cancer.

Strengths and limitations

Some limitations associated with this study should be mentioned. First, this was a retrospective study. The data were compiled from surgical cases at only two institutions, resulting in a limited sample size. Decisions regarding the extent of surgical procedures and lymph node dissection were made by each institution, and no unified standards had been established across facilities. The number of cases decreased further due to the narrowing of eligible cases through PSM and subgroup analysis. To confirm these results at a higher level of evidence, a prospective randomized study involving a larger number of cases is necessary. Second, this study did not collect data on tumor location, the distance between the tumor and the intersegmental plane in segmentectomy cases, or the relationship between the bronchus and the tumor. Locoregional recurrence after segmentectomy is a major concern, and securing adequate resection margins based on tumor location and bronchial relationships is critically important. We recommend that future studies prospectively collect such information to enable more detailed surgical analysis. The left upper lobe shares structural similarities with the right upper and middle lobes, but unlike these lobes, it is not separated by a lobar fissure. When performing a combined segmentectomy for left upper lobe lung cancer, ensuring adequate resection margins should also be important. Securing adequate margins becomes increasingly difficult as tumor size increases, and achieving appropriate margins is considered one of the challenges in expanding indications. Third, this study was unable to evaluate several factors potentially related to prognosis. Preoperative variables such as comorbidities unrelated to malignant disease and Eastern Cooperative Oncology Group performance status could not be accurately collected for all patients. Consequently, these factors could not be included in the PSM. Therefore, it is considered that the PSM could not completely eliminate differences between the two groups, and caution is required in interpreting the results. Postoperative pathological factors were also not examined. Factors such as histological subtype, visceral pleural invasion, lymphovascular invasion, and the presence or absence of spread through air spaces are important factors associated with postoperative recurrence. Programmed death-ligand 1 expression in tumors is an important factor in selecting postoperative treatment and may influence prognosis; however, this study was unable to evaluate it.

Fourth, this study was unable to evaluate postoperative respiratory function. Preserving lung tissue and maintaining postoperative respiratory function are two of the advantages of segmentectomy. The combined segmentectomy focused on in this study shares similarities with lobectomy, and the extent to which respiratory function can be preserved remains unclear. Furthermore, most patients in this study had cN0 disease, and after PSM, cN0 cases accounted for the majority. Therefore, the results of this study should be applied primarily to cN0 cases, and their applicability to cN1 or more advanced disease remains uncertain. Finally, differences in lymph node dissection were also observed between the L and S groups before and after PSM, and these factors may also contribute to long-term prognosis and local recurrence.

Despite these limitations, our findings remain relevant in expanding the indications for combined segmentectomy in left upper-lobe lung cancer. As mentioned earlier, locoregional recurrence, particularly marginal recurrence, is a concern following segmentectomy. Therefore, securing safe resection margins is crucial (2,5,11-14). Although this study could not evaluate the distance between the resection margin and the tumor, no cases of recurrence at the resection margin were observed. Also, there was no difference in the rate of other locoregional or distant recurrence. If margins can be secured, combined segmentectomy may be indicated for more advanced cases of left upper-lobe lung cancer. The preservation of postoperative respiratory function is considered one of the advantages of segmentectomy. According to reports, postoperative respiratory function is better preserved in segmentectomy when fewer segments are resected; pulmonary function after segmentectomy decreased with an increasing number of resected segments (4,5,15,16). Regarding tri-segmentectomy, some reports indicate that due to the larger resection area, the postoperative preservation of respiratory function is not significantly different from left upper lobectomy (17,18). Further verification is needed regarding the effectiveness of combined segmentectomy, particularly tri-segmentectomy, in preserving postoperative respiratory function. Nevertheless, the advantages of segmentectomy include not only preservation of respiratory function but also a reduction in postoperative complications and a shorter drainage placement period (2,19). Compared to lobectomy, segmentectomy often requires dissection of blood vessels and bronchi to more peripheral areas, sometimes necessitating more advanced surgical techniques. However, in this study, combined segmentectomy showed no difference in perioperative outcomes compared to lobectomy. Furthermore, postoperative complications such as arrhythmia were less frequent than with lobectomy. According to some reports, tri-segmentectomy results in less bronchial displacement compared to lobectomy (20). These findings suggest that combined segmentectomy may be an effective surgical option for left upper lobe lung cancer.

In this study, although cases with more advanced disease were observed in the L group before PSM, no significant difference was observed in long-term prognosis. In a multivariable analysis evaluating recurrence risk, SUV values on PET-CT emerged as an independent risk factor. Previous reports have demonstrated that elevated SUV values in tumors prior to surgery are associated with an increased risk of postoperative recurrence (21,22). In this study as well, it is possible that the treatment outcomes between the two groups became comparable because patients with advanced tumors exhibiting high SUV values underwent lobectomy prior to matching. SUV values might be useful in determining the surgical approach between lobectomy and segmentectomy, but further research is needed, including establishing cutoff values.

In this study, there was no difference between both groups; however, a small number of patients with tumors other than non-small cell lung cancer (NSCLC), such as neuroendocrine tumors, were included. In clinical practice, NSCLC usually cannot be reliably diagnosed before surgery. Furthermore, while this study did not evaluate histological subtypes or histological recurrence risk factors, these factors are also often difficult to assess preoperatively. In these respects, this study also aligns with actual clinical practice.

Comparison with similar research

Recently, multi-institutional randomized clinical trials (JCOG0802/WJOG4607L and CALGB140503) demonstrated the clinical value of segmentectomy in NSCLC and expanded its surgical indications (2,3). However, this benefit has been limited to patients with NSCLC with small peripheral sizes. We focused on the unique feature that the left upper lobe resembles the right upper and middle lobes, and evaluated the usefulness of combined segmentectomy for left upper lobe lung cancer. This study complements existing evidence and explores the potential for expanding the indications for segmentectomy limited to the left upper lobe. Similar studies have been conducted before. Iwasaki et al. reported equivalent long-term survival between left upper tri-segmentectomy and lobectomy in patients with cStage IA tumors ≤2 cm located in the upper division. However, the study was limited by a small sample size and its single-institution retrospective design (23). Subsequently, several studies were reported, but these focused on early-stage cases (12,24,25). Witte et al. subsequently demonstrated comparable survival and recurrence outcomes between lobectomy and split-lobe resections, including tumors >2 cm, using a pair-matched analysis (26). Aprile et al. compared lobectomy, tri-segmentectomy, and lingulectomy in patients with pT1–T2 disease and reported no significant differences in OS, although lingulectomy tended to be associated with inferior outcomes (27). These studies suggest the potential equivalence of lobectomy and combined segmentectomy for left upper lobe lung cancer; however, these reports had small sample sizes, and further research is needed to evaluate other factors such as CTR and SUV values. In recent years, Tane et al. reported that in cStage I NSCLC with a solid tumor >2 cm, although there was no difference in OS, RFS was reduced in the segmentectomy group (28). Liu et al. reported that even for tumors >2 cm, tri-segmentectomy and lingulectomy for left upper lobe resection did not affect long-term prognosis, but did not perform stratification based on the CTR (29). Our study was consistent with previous research, finding no difference in long-term prognosis between lobectomy and combined segmentectomy for left upper lobe lung cancer. Subgroup analysis of tumors >2 cm and with a CTR >0.5 showed no difference in OS or RFS, and no increase in locoregional recurrence was observed. This finding may suggest the potential for expanding the indications for combined segmentectomy in left upper lobe lung cancer in the future. In this study, SUV values were identified as a risk factor for recurrence in left upper lobe lung cancer. In recent years, it has been reported that SUV values, in addition to the CTR, may serve as a recurrence risk factor even in cases of sublobar resections (30,31). To achieve more precise surgical selection for left upper lobe lung cancer, detailed studies incorporating additional factors such as SUV values and pathological recurrence factors are necessary.

Explanations of findings

This study suggests that combined segmentectomy holds potential as a treatment option not only for small peripheral tumors but also for tumors >2 cm in size with a CTR >0.5. If a safe resection margin is secured, locoregional recurrence may potentially be suppressed to a degree comparable to lobectomy. This may expand surgical treatment options for patients for whom lung preservation is desirable based on underlying conditions and overall health status.

Implications and actions needed

The choice between lobectomy and segmentectomy for lung cancer requires comprehensive consideration of numerous factors beyond tumor size and CTR, necessitating tailored surgical selection for each case. Future research efforts should aim to refine patient selection criteria for segmentectomy while considering other risk factors, evaluate prognosis in cases of cN1 or more advanced cases, explore the integration of adjuvant therapies, and investigate long-term outcomes beyond the 5-year mark to fully ascertain the significance of this procedure in the evolving therapeutic landscape of early-stage lung cancer.

Conclusions

In this retrospective study of the left upper-lobe lung cancer, tri-segmentectomy or lingulectomy may provide a prognosis and locoregional tumor control comparable with that of lobectomy, even in disease that exceeds the current criteria for its use. Combined segmentectomy for left upper lobe lung cancer holds potential as a treatment option for more advanced tumors, and these findings suggest that patient selection is central to its safe application. Further large-scale studies are needed to evaluate its expanded indications.

Acknowledgments

We would like to thank Editage (www.editage.com) for their English language editing service.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1-2568/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1-2568/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1-2568/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1-2568/coif). H.S. belongs to an endowed department (NITORI Co., Ltd. and HOKUYAKU TAKEYAMA Holdings, Inc.). 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. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This retrospective study was approved by the ethics committees of Hokkaido University Hospital (approval No. 024-0417) and Sapporo Minami-Sanjo Hospital (approval No. R6-6). The requirement for informed consent was waived due to the retrospective nature of the study.

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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