Lobectomy, segmentectomy, and wedge resection for elderly patients with solid-predominant stage I NSCLC: survival, pulmonary function, and postoperative outcomes

Introduction

Lung cancer is a leading global malignancy, constituting up to 11.4% of all cancer diagnoses and accounting for 18% of cancer-related mortality (1,2). Non-small cell lung cancer (NSCLC), the dominant subtype of lung cancer, is highly prevalent in the elderly (defined as age ≥60 years at diagnosis) (1,3). Historically, the Lung Cancer Study Group (LCSG) 821 trial established lobectomy as the standard of care for pathological stage I NSCLC (4).

In clinical practice, lung nodules, ranging from pure ground-glass opacities to solid nodules, are evaluated using the consolidation-to-tumor ratio (CTR). Nodules with a CTR > 0.5 are clinically defined as solid-predominant. Additionally, researchers have identified the solid-predominant nodule as a valuable predictor of tumor invasiveness, underscoring the importance of radical lobectomy (5-8).

However, while lobectomy ensures radical resection and significantly improves recurrence-free survival in solid-predominant nodules, a substantial proportion of elderly patients cannot tolerate the loss of pulmonary function associated with the procedure (9-14). Sublobar resection (including segmentectomy and wedge resection) serves as a viable alternative for patients who are intolerant of lobectomy, as it involves a limited extent of resection, preserves more pulmonary function, and is associated with a lower incidence of postoperative complications.

Recent landmark trials, such as the Japan Clinical Oncology Group Study 0802 (JCOG0802) and Cancer and Leukemia Group B 140503 (CALGB 140503), have demonstrated the non-inferiority of sublobar resection regarding survival, alongside a favorable safety profile compared with lobectomy; the former focused exclusively on segmentectomy, while the latter included both segmentectomy and wedge resection (10,15). Nevertheless, these studies primarily focused on small-sized or ground-glass opacity (GGO)-predominant tumors. Previous literature has not specifically addressed whether elderly patients with stage I solid-predominant NSCLC—a population traditionally considered more suitable for lobectomy—may derive comparable oncologic outcomes and potential functional benefits from segmentectomy or wedge resection.

To address this knowledge gap, we conducted a retrospective study investigating how different surgical extents affect the prognosis and postoperative outcomes in elderly patients with stage I solid-predominant NSCLC, aiming to establish evidence for precision treatment in this demographic. We present this article in accordance with the STROBE reporting checklist (16) (available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0414/rc).

Methods

Study design and ethical approval

This was a retrospective single-center observational study based on the prospectively maintained Western China Lung Cancer Database, Department of Thoracic Surgery, West China Hospital, Sichuan University. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committee on Biomedical Research of West China Hospital, Sichuan University (No. 2025-2064) and individual consent for this retrospective analysis was waived.

Patient selection

We identified patients with primary NSCLC who underwent surgical resection at West China Hospital, Sichuan University, between April 20, 2009 and December 31, 2020. Eligible patients met the following criteria: (I) age ≥60 years; (II) pathological stage I disease according to the 9th edition TNM staging system; and (III) solid-predominant nodules with a CTR >0.5 on preoperative computed tomography (CT), independently assessed by two radiologists. Patients were excluded if they (I) had received preoperative antitumor therapy; (II) had undergone more than one pulmonary radical resection; or (III) had missing key clinical or survival data. Patients were categorized into lobectomy, segmentectomy, and wedge resection groups.

Data collection and follow-up

Baseline clinicopathological data included age, sex, smoking status, Charlson Comorbidity Index (CCI), preoperative pulmonary function, histological subtype, differentiation, lymphovascular invasion (LVI), perineural invasion (PNI), visceral pleural invasion (VPI), tumor diameter, surgical details, and postoperative complications graded by the Clavien-Dindo classification. Patients with missing key variables required for eligibility determination, exposure classification, or survival analysis were excluded from subsequent analyses, whereas missing data in non-key variables were retained and categorized as “unknown”. Follow-up was performed through outpatient visits and telephone interviews according to the institutional protocol: every 3–6 months during the first 2 years, every 6 months for the next 3 years, and annually thereafter. The cut-off date for survival analysis was September 26, 2025 (17).

Quantitative CT analysis for pulmonary function

To evaluate postoperative functional preservation, preoperative and postoperative chest CT scans obtained more than 3 months after surgery were analyzed using 3D Slicer. Lung parenchyma with attenuation values from −910 to −600 HU was defined as functional lung volume (Figure 1) (18,19). The functional lung volume preservation rate was calculated as postoperative functional lung volume divided by preoperative functional lung volume. CT-estimated postoperative forced expiratory volume in 1 second (FEV1) and CT-estimated postoperative forced vital capacity (FVC) were estimated by multiplying preoperative FEV1 %pred and FVC %pred by this preservation rate.

Figure 1 Representative computed tomography images demonstrating lung volume segmentation. Axial (A) view; (B) sagittal view. The red line outlines the whole lung, functional lung parenchyma (−910 to −600 HU) is shown in yellow, and excluded tissues are shown in blue.

Outcome measurement

The primary endpoint was overall survival (OS). Secondary endpoints were lung cancer-specific survival (LCSS) and disease-free survival (DFS). OS was defined as the interval from surgery to death from any cause or last follow-up. LCSS was defined as the interval from surgery to lung cancer-related death or last follow-up. DFS was defined as the interval from surgery to recurrence, metastasis, lung cancer-related death, or last follow-up.

Statistical analysis

Propensity score-based weighting was used to reduce baseline imbalance among the three surgical groups. Propensity scores were estimated using a multinomial propensity score model including clinically relevant covariates, such as age, sex, smoking status, CCI category, CTR, histological type, preoperative pulmonary function, surgical approach, pathological stage, tumor site, differentiation grade, and VPI. Inverse probability of treatment weighting (IPTW) based on the average treatment effect (ATE) estimand was applied as the primary weighting approach to estimate the treatment effect in the overall study population. In addition, overlap weighting based on the average treatment effect in the overlap population (ATO) estimand was performed as a sensitivity analysis to evaluate patients with comparable probabilities of receiving any of the three surgical procedures. Covariate balance before and after weighting was assessed using standardized mean differences (SMDs), with an SMD <0.1 indicating acceptable balance.

Continuous variables were summarized as mean ± standard deviation or median [interquartile range], as appropriate, and categorical variables were summarized as frequency (%). Group differences were compared using Student’s t-test or Mann-Whitney U test for two-group comparisons, and analysis of variance or the Kruskal-Wallis test for three-group comparisons, as appropriate. Categorical variables were compared using the chi-square test or Fisher’s exact test, as appropriate. Postoperative complication severity was evaluated using the Clavien-Dindo classification, and differences in grade distribution among the three groups were compared using the Kruskal-Wallis test. CT-estimated postoperative FEV1 and FVC were calculated based on the quantitative CT-derived functional lung volume preservation ratio.

Survival outcomes, including OS, LCSS, and DFS were analyzed using the Kaplan-Meier method and compared with the log-rank test. Cox proportional hazards models were used for univariable and multivariable analyses. Subgroup analyses for OS, LCSS, and DFS were presented as forest plots, and interaction tests were performed to evaluate whether the association between surgical extent and survival differed across subgroups. All analyses were performed using R software (version 4.5.1), and a two-sided P<0.05 was considered statistically significant.

Results

Patient characteristics

Based on the flowchart (Figure 2), electronic medical records from April 20, 2009, to December 31, 2020, were retrospectively reviewed. A total of 2,111 patients were initially included. After excluding those who met the predefined exclusion criteria, the final study cohort comprised 1,402 patients, including 1,187 who underwent lobectomy. Baseline characteristics differed across surgical groups. The female proportion was 44.6%, 53.1%, and 42.5% in the lobectomy, segmentectomy, and wedge resection groups, respectively. Patients undergoing lobectomy exhibited more advanced tumor characteristics compared with those undergoing segmentectomy or wedge resection. Before weighting, the lobectomy group had the highest proportion of stage IB disease (68.7% vs. 50.0% vs. 57.5%, P<0.001), and pure-solid nodules were also more frequent in the lobectomy group than in the segmentectomy group, although the wedge resection group showed a similarly high proportion (97.3% vs. 86.7% vs. 95.4%, P<0.001). Peripheral tumors accounted for 92.9%, 100.0%, and 100.0% of cases in the lobectomy, segmentectomy, and wedge groups, respectively (P<0.001). R0 resection was achieved in nearly all patients across the three groups, with no significant between-group difference (99.2% vs. 99.2% vs. 100.0%, P=1.00). Poorly differentiated tumors were more common in the lobectomy and wedge resection groups than in the segmentectomy group (41.0% vs. 16.4% vs. 36.8%, P<0.001). In contrast, patients who underwent wedge resection tended to have poorer baseline physiological status, as reflected by older median age (66 vs. 67 vs. 72 years, P<0.001) and a higher proportion of severe comorbidity burden, defined as CCI ≥6 (8.26% vs. 14.8% vs. 23.0%, P<0.001); preoperative comorbidities stratified by surgical extent are summarized in Table S1. Chronic pulmonary disease was the most common comorbidity and was numerically more frequent in the wedge resection group than in the segmentectomy and lobectomy groups (39.1% vs. 28.9% vs. 26.9%, P=0.05). Other preoperative comorbidities were relatively infrequent and showed no significant differences among the three surgical groups. Segmentectomy patients were more likely to have IA1–IA2 tumors and left upper lobe lesions, whereas lobectomy was more frequently performed for stage IB and pure-solid tumors. The mean follow-up time for the overall cohort was 6 years, and the longest follow-up time was 15 years.

Figure 2 Flowchart of patient selection. CTR, consolidation-to-tumor ratio; NSCLC, non-small cell lung cancer.

To address confounding related to non-random surgical selection, we performed two complementary weighting analyses. IPTW based on the ATE estimand was used as the primary weighting approach because it estimates the ATE in the overall study population. In addition, overlap weighting based on the ATO estimand was performed as a sensitivity analysis to focus on patients who had a clinically plausible probability of receiving any of the three surgical procedures. As shown in Table 1, overlap weighting achieved better covariate balance than ATE weighting for most baseline variables, including age, smoking status, CCI category, pure-solid nodules, resection site, and pathological stage, with most SMDs below 0.1. These analyses allowed us to evaluate the association between surgical extent and prognosis both in the overall cohort and in the more comparable overlap population.

Postoperative morbidity and complication severity

Patients undergoing lobectomy had a longer postoperative length of stay than those undergoing segmentectomy or wedge resection, with median postoperative hospital stays of 6.0 days (IQR, 4.0–8.0), 5.0 days (IQR, 3.0–6.0), and 5.0 days (IQR, 4.0–7.0), respectively (P<0.001). To further characterize postoperative recovery and surgical safety, the overall profile of postoperative complications stratified by surgical extent and Clavien-Dindo grade is summarized in Figure 3 and Table S1. Across the entire cohort, pleural space-related events predominated, with prolonged drainage (>7 days) being the most common complication, followed by prolonged air leak (>5 days), pneumonia, and subcutaneous emphysema. Among the three surgical groups, prolonged drainage occurred most frequently after lobectomy, followed by wedge resection and segmentectomy; however, the difference did not reach statistical significance (14.0% vs. 7.8% vs. 8.0%, P=0.06). Prolonged air leak was also numerically more common after lobectomy than after segmentectomy or wedge resection, but without a significant between-group difference (7.4% vs. 4.7% vs. 6.9%, P=0.59). Similarly, no significant differences were observed for pneumonia (2.9% vs. 3.9% vs. 4.6%, P=0.41), chylothorax (1.0% vs. 0.8% vs. 1.1%, P=0.85), or subcutaneous emphysema (2.0% vs. 1.6% vs. 1.1%, P=1.00). Most postoperative complications were minor to moderate events, mainly Clavien-Dindo grades I–II. Severe complications were uncommon overall; grade III complications occurred in 2.7%, 0.8%, and 1.1% of patients in the lobectomy, segmentectomy, and wedge resection groups, respectively, while grade IV complications were observed only in the lobectomy group and remained rare (0.4%). Overall, the distribution of Clavien-Dindo grades demonstrated a significant difference among the three surgical groups (P=0.01).

Figure 3 Spectrum and Clavien-Dindo grade of postoperative complications stratified by surgical extent. GI, gastrointestinal; LOB, lobectomy; SEG, segmentectomy; WR, wedge resection.

Long term prognosis outcome with different surgery extent

After IPTW using the ATE estimand, Kaplan-Meier survival analyses demonstrated significant differences in survival outcomes among the three surgical groups. Patients who underwent wedge resection had the worst survival outcomes compared with those undergoing lobectomy or segmentectomy. In the ATE-weighted cohort, wedge resection showed markedly lower 10-year OS than lobectomy and segmentectomy (49.2% vs. 69.1% vs. 79.1%), lower 10-year LCSS (57.2% vs. 78.7% vs. 82.2%) and lower 10-year DFS (47.7% vs. 61.1% vs. 58.8%). In multivariable Cox analysis, wedge resection was associated with significantly worse survival compared with lobectomy (OS: HR =3.32, 95% CI: 2.33–4.75; LCSS: HR =4.17, 95% CI: 2.76–6.29; DFS: HR =2.76, 95% CI: 1.99–3.84 all P<0.001). However, segmentectomy showed comparable survival outcomes to lobectomy, with no statistically significant differences in OS, LCSS, or DFS (OS: HR =1.03, 95% CI: 0.62–1.71; LCSS: HR =1.22, 95% CI: 0.68–2.21; DFS: HR =0.99, 95% CI: 0.65–1.50) (Figure 4A-4C).

Figure 4 Kaplan-Meier survival curves comparing lobectomy versus segmentectomy versus wedge resection after propensity score-based weighting. (A-C) OS, LCSS, and DFS after IPTW using the ATE estimand. (D-F) OS, LCSS, and DFS after overlap weighting using the ATO estimand. P values were calculated using the log-rank test; shaded areas indicate 95% confidence intervals. ATE, average treatment effect; ATO, average treatment effect in the overlap population; DFS, disease-free survival; HR, hazard ratio; IPTW, inverse probability of treatment weighting; LCSS, lung cancer-specific survival; LOB, lobectomy; OS, overall survival; SEG, segmentectomy; WR, wedge resection.

We further performed overlap weighting using the ATO estimand as a sensitivity analysis to evaluate patients with comparable probabilities of receiving any of the three surgical procedures. The ATO-weighted Kaplan-Meier curves showed a consistent pattern. Wedge resection remained associated with the poorest survival outcomes, with 10-year OS, LCSS, and DFS rates of 48.2%, 55.9%, and 46.3%, respectively. Compared with lobectomy, wedge resection was associated with significantly worse OS, LCSS, and DFS (OS: HR =3.32, 95% CI: 2.33–4.75; LCSS: HR =4.17, 95% CI: 2.76–6.29; DFS: HR =2.76, 95% CI: 1.99–3.84; all P<0.001). In contrast, segmentectomy again showed no significant survival disadvantage compared with lobectomy (OS: HR =1.03, 95% CI: 0.62–1.71; LCSS: HR =1.22, 95% CI: 0.68–2.21; DFS: HR =0.99, 95% CI: 0.65–1.50) (Figure 4D-4F).

In addition, recurrence and metastasis patterns were compared among the three surgical groups. No statistically significant differences were observed in any local recurrence or distant metastasis pattern. Pulmonary metastatic nodules were the most common local recurrence pattern, whereas bone and brain were the most frequent distant metastatic sites. Although wedge resection showed numerically higher rates of pulmonary metastatic nodules, bone metastasis, brain metastasis, and other distant metastases, these differences did not reach statistical significance (Table S2).

Subgroup survival analysis in patients aged ≥70 years

In the subgroup of patients aged ≥70 years, the survival advantage of anatomical resection was further examined using both ATE- and ATO-weighted analyses. After IPTW using the ATE estimand, significant differences in 5-year OS, DFS, and LCSS were observed among the three surgical groups. Wedge resection showed substantially lower 5-year survival rates than lobectomy and segmentectomy (OS: 53.9% vs. 82.9% vs. 92.8%; LCSS: 60.5% vs. 89.2% vs. 94.9%; DFS: 45.3% vs. 76.8% vs. 87.8%; all log-rank P<0.001). In multivariable Cox analysis, wedge resection was associated with significantly worse outcomes compared with lobectomy (OS: HR =3.69, 95% CI: 2.22–6.14; LCSS: HR =6.70, 95% CI: 3.65–12.29; DFS: HR =3.76, 95% CI: 2.35–6.01), whereas segmentectomy was not associated with a significant survival disadvantage (OS: HR =0.90, 95% CI: 0.41–1.97; LCSS: HR =1.23, 95% CI: 0.45–3.36; DFS: HR =0.82, 95% CI: 0.41–1.64) (Figure 5A-5C).

Figure 5 Kaplan-Meier survival curves comparing lobectomy versus segmentectomy versus wedge resection after propensity score-based weighting in patients ≥70 years. (A-C) OS, LCSS, and DFS after IPTW using the ATE estimand. (D-F) OS, LCSS, and DFS after overlap weighting using the ATO estimand. P values were calculated using the log-rank test; shaded areas indicate 95% confidence intervals. ATE, average treatment effect; ATO, average treatment effect in the overlap population; DFS, disease-free survival; HR, hazard ratio; IPTW, inverse probability of treatment weighting; LCSS, lung cancer-specific survival; LOB, lobectomy; OS, overall survival; SEG, segmentectomy; WR, wedge resection.

The ATO-weighted sensitivity analysis confirmed these findings in the overlap population of elderly patients. Wedge resection continued to show the lowest 5-year OS, LCSS, and DFS rates (52.1%, 60.3%, and 43.3%, respectively), while segmentectomy maintained survival outcomes comparable to lobectomy. The increased risk associated with wedge resection remained evident for OS, LCSS, and DFS (OS: HR =3.69, 95% CI: 2.22–6.14; LCSS: HR =6.70, 95% CI: 3.65–12.29; DFS: HR =3.76, 95% CI: 2.35–6.01), whereas no significant differences were observed between segmentectomy and lobectomy (Figure 5D-5F).

Preservation of pulmonary function across different surgical extents

To evaluate the physiological impact of surgical extent, we compared the preoperative and CT-estimated postoperative pulmonary functions among the three groups (Table 2). Due to missing preoperative pulmonary function tests or lung CT imaging in some patients, only patients with complete data were included in this analysis (lobectomy, n=979; segmentectomy, n =111; wedge resection, n =75). Notably, patients undergoing wedge resection exhibited significantly worse preoperative baseline lung function compared with those receiving lobectomy or segmentectomy (median preoperative FEV1: 88.50% vs. 100.70% and 100.30%, respectively, P=0.002; preoperative FVC: 100.50% vs. 105.90% and 105.60%, P=0.022).

When evaluating the quantitative CT-derived functional lung volume preservation rate, segmentectomy numerically retained the highest proportion of functional lung parenchyma (median 86.60%), followed by lobectomy (82.90%) and wedge resection (82.16%). However, this overall variance among the three modalities did not reach statistical significance (P=0.663). However, the CT-estimated postoperative FEV1 significantly differed among the groups (P=0.04). Patients in the segmentectomy cohort achieved the highest CT-estimated postoperative FEV1 (89.11%), whereas the wedge resection group had the lowest (70.51%). Differences in CT-estimated postoperative FVC followed a similar trend but were not statistically significant (P=0.233).

Subgroup analysis

Patients were stratified into subgroups based on age, sex, smoking status, CCI score, preoperative FEV1/FVC, CTR, histological type, stage, differentiation grade, and VPI. Due to the low prevalence of LVI and PNI, these two variables were excluded from the subgroup analysis. Subgroup analyses were performed after IPTW, and interaction tests were used to evaluate whether the association between surgical extent and survival differed across strata.

For OS, segmentectomy generally showed survival outcomes comparable to lobectomy across most subgroups (Figure 6). Most interaction tests for the comparison between segmentectomy and lobectomy were not statistically significant, including age group (P for interaction =0.590), sex (P for interaction =0.125), CCI category (P for interaction =0.829), preoperative FEV1/FVC (P for interaction =0.183), CTR (P for interaction =0.123), histological type (P for interaction =0.561), stage (P for interaction =0.603), and VPI (P for interaction =0.155). However, significant interactions were observed for smoking status (P for interaction =0.039) and differentiation grade (P for interaction =0.001), indicating potential heterogeneity in the effect of segmentectomy across these strata. In contrast, wedge resection was associated with worse OS than lobectomy in most subgroups, but interaction tests were largely non-significant, suggesting that the unfavorable association of wedge resection was relatively consistent across patient subsets. Significant or borderline interactions were observed for stage (P for interaction =0.035) and smoking status (P for interaction =0.059).

Figure 6 Forest plot of subgroup analysis for OS after IPTW adjustment. HRs and 95% CIs are shown for segmentectomy (left) and wedge resection (right) versus lobectomy. Interaction P values assess heterogeneity across subgroups. ADC, adenocarcinoma; ASC, adenosquamous carcinoma; CCI, Charlson Comorbidity Index; CI, confidence interval; CTR, consolidation-to-tumor ratio; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; HR, hazard ratio; LOB, lobectomy; OS, overall survival; SCC, squamous cell carcinoma; SEG, segmentectomy; VPI, visceral pleural invasion; WR, wedge resection.

Subgroup analyses for LCSS and DFS showed broadly consistent patterns. For LCSS, the segmentectomy-versus-lobectomy comparison showed significant interaction only for differentiation grade (P for interaction =0.002), whereas most other variables, including age, sex, smoking status, CCI, preoperative FEV1/FVC, CTR, histological type, stage, and VPI, showed no significant interaction. For wedge resection versus lobectomy, interaction tests were also mostly non-significant, with a borderline interaction observed for stage (P for interaction =0.050) (Figure S1). For DFS, the segmentectomy-versus-lobectomy comparison showed significant interactions for sex (P for interaction =0.005), smoking status (P for interaction =0.006), preoperative FEV1/FVC (P for interaction =0.046), and CTR (P for interaction =0.032), while the remaining variables, including age, CCI, histological type, stage, differentiation grade, and VPI, showed no significant interactions. For the wedge resection-versus-lobectomy comparison, most DFS interaction tests were not statistically significant, except for sex and smoking status, both with P for interaction =0.046 (Figure S2). Overall, these subgroup analyses indicated that segmentectomy yielded survival outcomes generally comparable to lobectomy across most subgroups, whereas wedge resection was consistently associated with inferior OS, LCSS, and DFS.

Discussion

In this retrospective study, we included 1,402 patients aged 60 years or older with stage I NSCLC predominantly presenting as solid nodules. We found no significant difference in survival benefit between lobectomy and segmentectomy. In contrast, wedge resection showed the worst survival outcomes, inferior to both segmentectomy and lobectomy, thereby providing novel insights for selecting the optimal extent of surgical resection. Subgroup analyses further revealed that, compared with lobectomy, wedge resection was associated with a higher HR across most subgroups, particularly among patients with pure solid nodules. Notably, wedge resection still conferred a higher HR in patients with high-risk factors, such as a CCI ≥6, whereas segmentectomy demonstrated consistent survival benefits in these patients when compared with lobectomy. In addition, we further performed survival analyses in patients aged ≥70 years to evaluate the applicability and robustness of our findings in a more elderly population. The results were generally consistent with the main analysis: segmentectomy showed no significant survival disadvantage compared with lobectomy, whereas wedge resection remained associated with worse survival outcomes. These findings further support the consistency of our main conclusions in older patients.

Compared with lobectomy, the other two surgical procedures are generally associated with less surgical trauma and greater preservation of lung parenchyma, theoretically reducing postoperative risks. Therefore, we specifically compared postoperative outcomes among the three surgical approaches and used the Clavien-Dindo classification system to quantify postoperative complications. The Wilcoxon rank-sum test showed that the lobectomy group had significantly higher Clavien-Dindo grades than the other two groups, indicating a greater burden of complications and relatively worse postoperative outcomes. The occurrence of complications inevitably leads to prolonged hospitalization. This was consistent with our findings: the median postoperative length of stay was 6 days in the lobectomy group, compared with 5 days in the other two groups. This may further increase the economic burden and potential psychological distress of patients (20-22). Our results are consistent with previous studies evaluating postoperative outcomes across different extents of resection in elderly patients with stage I NSCLC, particularly those aged >70 years (23). Therefore, our findings highlight the importance of postoperative rehabilitation, especially for patients undergoing lobectomy. Feasible strategies include preoperative exercise training and continuous postoperative monitoring (24,25). However, despite the higher postoperative risk associated with lobectomy, patients undergoing lobectomy still demonstrated better long-term prognosis.

Since postoperative pulmonary function was recognized as a factor associated with quality of life following lung cancer surgery, we focused on the impact that different surgical extent brought to pulmonary function. By calculating the functional lung preservation ratio using quantitative CT, CT-estimated postoperative FEV1 and CT-estimated postoperative FVC can be estimated, and the accuracy of this approach has been validated in previous studies (26,27). Our results revealed that when patients have poor baseline physical conditions and insufficient pulmonary functional reserve, wedge resection is often considered a “necessary” or unavoidable choice by clinicians (28). We also noticed that the difference in preserved functional lung volume rate between lobectomy and wedge resection was smaller than expected, while segmentectomy had a higher preserved functional lung volume rate numerically. Although similar findings have rarely been reported, this observation may be interpreted from anatomical and respiratory physiological perspectives. Lobectomy and segmentectomy are both anatomical resections that generally follow natural anatomical boundaries, which may help preserve a more physiological ventilation-perfusion relationship in the residual lung and facilitate compensatory expansion of the remaining healthy parenchyma after surgery (29). By contrast, wedge resection is a non-anatomical resection in which the staple line may directly traverse the surrounding lung parenchyma, potentially causing local mechanical traction or a “plication effect” that could reduce compliance and limit compensatory expansion of the preserved lung tissue (30). Although staplers are also routinely used to divide the intersegmental plane during segmentectomy at our center, segmentectomy is still performed along anatomical intersegmental boundaries. Therefore, the mechanical effect of stapling during segmentectomy may differ from that of wedge resection, in which the staple line is less constrained by anatomical planes. Nevertheless, this explanation remains hypothetical and should be interpreted with caution, as the specific mechanical impact of different stapling patterns was not directly assessed in this study. Collectively, in terms of functional lung preservation, lobectomy may achieve a level comparable to wedge resection due to the efficient compensatory expansion of the remaining lobes, whereas segmentectomy may provide a favorable balance of anatomical boundaries with minimal resection volume, achieving the best compromise between parenchymal preservation and postoperative compensatory capacity (26). Furthermore, due to poorer preoperative pulmonary function, patients undergoing wedge resection also exhibited significantly lower CT-estimated postoperative FEV1% compared with those undergoing segmentectomy or lobectomy. This finding suggests that the inferior functional outcomes observed in the wedge resection group may largely reflect baseline patient characteristics rather than the surgical procedure itself. Taken together, these results highlight the importance of considering both surgical extent and preoperative functional reserve when evaluating postoperative pulmonary function.

Our subgroup analyses further supported the robustness of the main findings; however, these results should be interpreted primarily based on interaction tests rather than solely on the statistical significance of HRs or P values within individual subgroups. In the comparison between segmentectomy and lobectomy, most interaction tests for OS, DFS, and LCSS were not statistically significant, suggesting that the comparable survival outcomes between the two procedures were generally consistent across most clinically relevant subgroups. Although significant interactions were observed for several variables, such as smoking status and differentiation grade for OS, sex, smoking status, preoperative FEV1/FVC, and CTR for DFS, and differentiation grade for LCSS, these findings should be considered exploratory given the multiple subgroup comparisons and limited number of events in some strata, and should not be interpreted as definitive evidence that the effect of segmentectomy was substantially modified in specific subgroups. For wedge resection, its association with poorer survival outcomes was observed across a broad range of patient and tumor subgroups. Importantly, most interaction tests for wedge resection versus lobectomy were not statistically significant, indicating that the unfavorable prognostic association of wedge resection was generally consistent across different subgroups rather than being confined to a specific patient or tumor characteristic. Although significant or borderline interactions were observed for stage in OS, sex and smoking status in DFS, and stage in LCSS, these findings should also be interpreted with caution because of the exploratory nature of subgroup analyses and the relatively small sample size and event numbers in some strata. Therefore, the main value of the subgroup analyses was to assess the consistency of the primary findings across clinically relevant populations rather than to establish the superiority or inferiority of a surgical procedure within any single subgroup. Overall, the lack of significant interaction for most covariates suggested that our main findings were largely robust: among elderly patients with solid-predominant stage I NSCLC, segmentectomy showed long-term survival outcomes generally comparable to lobectomy, whereas wedge resection was associated with worse OS, DFS, and LCSS. Future prospective studies with larger sample sizes are needed to further validate these potential subgroup differences.

With growing interest in comparing survival outcomes across different extents of surgical resection, increasing efforts have been made to determine whether sublobar resection can be considered a feasible alternative to lobectomy. However, previous studies have yielded conflicting results. The CALGB 140503 trial demonstrated no significant differences in OS, DFS, or rates of local or distant recurrence between sublobar resection and lobectomy in patients with clinically staged T1N0 non-small cell lung cancer (15). Additionally, a retrospective study based on the National Cancer Database reported no significant difference in OS between sublobar resection and lobectomy among patients with a maximum tumor diameter of 2–3 cm (31). However, a more recent study including 19,778 patients, of whom 8,283 underwent wedge resection has provided deeper insights, demonstrating that wedge resection does not achieve survival outcomes comparable to those of segmentectomy, whereas segmentectomy confers survival benefits closer to lobectomy and superior to wedge resection (32). Building on previous studies, the novelty of our study lies in its focus on elderly patients with solid-predominant stage I NSCLC and its separate evaluation of lobectomy, segmentectomy, and wedge resection. Unlike previous studies that often grouped segmentectomy and wedge resection together as sublobar resection, our analysis revealed distinct prognostic profiles between these two procedures (33,34). By integrating long-term survival, CT-estimated postoperative pulmonary function, and perioperative complications, we provided a comprehensive assessment of the balance between oncologic efficacy, functional preservation, and surgical safety. Furthermore, the combined use of ATE-based IPTW and ATO-based overlap weighting, together with subgroup analysis in patients aged ≥70 years, strengthened the robustness and clinical relevance of our findings.

Our study has several limitations. First, this was a single-center retrospective study. Although IPTW, overlap weighting, and multivariable adjustment were applied to balance baseline covariates and reduce treatment selection bias, residual selection bias and unmeasured confounding could not be completely eliminated. The choice of surgical procedure was influenced by multiple factors, including baseline patient condition, tumor location, pulmonary functional reserve, comorbidity burden, and surgeon judgment. In particular, patients undergoing wedge resection may represent a distinct subgroup with poorer physiological reserve and limited surgical tolerance. Therefore, our findings should be interpreted as associations between surgical extent and prognosis rather than as strict causal effects, and the poorer outcomes observed after wedge resection should not be attributed solely to the surgical procedure itself. Second, owing to the relatively strict inclusion criteria, the numbers of patients undergoing segmentectomy and wedge resection were substantially smaller than the number undergoing lobectomy. This was particularly relevant in some subgroup analyses, where the number of events was limited. Although we performed an additional subgroup analysis in patients aged ≥70 years to assess the applicability and robustness of our findings in a more elderly population, further analyses using more advanced age cutoffs, such as ≥75 or ≥80 years, were not feasible because of the limited sample size and event numbers. As a result, some subgroup estimates may be unstable and accompanied by wide confidence intervals. Therefore, subgroup findings should be interpreted primarily as exploratory, and the superiority or inferiority of a surgical procedure in a specific subgroup should not be inferred solely from HRs or P values within individual strata. Third, postoperative pulmonary function data were not completely available for all patients. In this study, CT-estimated postoperative FEV1 and FVC were derived from the quantitative CT-based functional lung volume preservation ratio, rather than from standardized longitudinal postoperative spirometry in all patients. Therefore, the reliability and generalizability of the pulmonary function-related findings are limited, and these results should be interpreted with caution and further validated in prospective studies with complete preoperative and postoperative pulmonary function follow-up.

Overall, although our findings suggest that segmentectomy may achieve a favorable balance between long-term oncologic outcomes and pulmonary function preservation in elderly patients with solid-predominant stage I NSCLC, whereas wedge resection was associated with worse prognosis, these results require further validation in future multicenter, large-scale, prospective studies.

Conclusions

In elderly patients with solid-predominant stage I NSCLC, segmentectomy showed long-term survival outcomes generally comparable to lobectomy, and both procedures were associated with better survival than wedge resection. Segmentectomy may provide a more favorable balance between oncologic outcomes and pulmonary function preservation. In contrast, wedge resection was associated with inferior survival and did not show a clear advantage in functional lung preservation. These findings suggest that, for selected patients who are able to tolerate anatomical resection, segmentectomy may represent a reasonable alternative to lobectomy; whereas for patients with multiple clinically feasible surgical options, wedge resection may not be preferentially recommended. Future prospective studies are warranted to further validate these findings.

Acknowledgments

During the preparation of this work, the authors used ChatGPT-5 in order to enhance its language and readability. After using this tool, the authors reviewed and edited the content as needed and take full responsibility for the content of the published article.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0414/rc

Data Sharing Statement: Available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0414/dss

Peer Review File: Available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0414/prf

Funding: This work was supported by the Prevention and Control of Emerging and Major Infectious Diseases–National Science and Technology Major Project (No. 2025ZD01907200, to M.L.), the National Natural Science Foundation of China (No. 82102968, to J.Z.), and the Sichuan Science and Technology Program (No. 2024NSFSC1293, to A.L.).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0414/coif). All authors report that this study was supported by the National Natural Science Foundation of China, the Sichuan Science and Technology Program, and the Prevention and Control of Emerging and Major Infectious Diseases–National Science and Technology Major Project. The authors have no other 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. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committee on Biomedical Research of West China Hospital, Sichuan University (No. 2025-2064) and individual consent for this retrospective analysis was waived.

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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