Structured training and early outcomes in major pulmonary resections by a junior thoracic surgeon: a retrospective observational study

Introduction

Videoassisted thoracoscopic surgery (VATS) lobectomy is the established standard for early-stage non-small cell lung cancer (NSCLC), offering superior perioperative outcomes compared to open surgery (1). Recently, uniportal VATS has been increasingly adopted for its potential to reduce invasiveness while maintaining comparable results (2). In parallel, anatomical segmentectomy has emerged as an oncologically valid alternative to lobectomy for small, peripheral NSCLC, with recent randomized trials (JCOG0802/WJOG4607L, CALGB/Alliance 140503) demonstrating its non-inferiority in survival outcomes (3,4). However, segmentectomy requires precise anatomical knowledge and advanced thoracoscopic techniques, posing additional technical challenges for junior surgeons (5).

Studies analyzing large institutional experiences suggest that proficiency is typically achieved after approximately 50–60 cases, underscoring the influence of prior minor VATS experience, institutional volume, and structured mentorship on this learning curve (6,7). The transition from fellowship to independent practice represents a critical phase in the professional development of thoracic surgeons, marked by a steep learning curve, especially for technically demanding procedures like major pulmonary resections (8,9). While prior studies have examined learning curves for VATS lobectomy or outcomes among high-volume surgeons, few have comprehensively analyzed the progression of a single junior surgeon under structured support and systematic case selection.

To address this gap, we evaluated the operative experience of a junior thoracic surgeon over the first three years post-board certification, focusing on trends in case volume, operative efficiency, and perioperative outcomes, with particular attention to the deliberate integration of segmentectomy. These findings aim to inform future strategies for mentorship and procedural training during early surgical careers. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1432/rc).

Methods

Patient population and study design

This retrospective observational study included all thoracic surgeries performed by a single board-certified thoracic surgeon from June 2022 to June 2025, excluding a 3-year military service period following board certification. Data were extracted from a prospectively maintained institutional database. All operations were classified into major pulmonary resections (segmentectomy or lobectomy) and other thoracic procedures. A total of 123 patients underwent major pulmonary resection during this period, including primary lung cancer, pulmonary metastasis, and infectious disease cases. For the evaluation of quarterly trends in operative time, blood loss, and case volume, all 123 patients were analyzed. Perioperative outcomes were compared between lobectomy and segmentectomy. For cumulative sum (CUSUM) analysis, however, only patients with primary lung cancer who underwent anatomical segmentectomy or lobectomy (n=113) were included to ensure oncologic homogeneity. All segmentectomies were anatomical resections, not wedge resections. Demographic, intraoperative, and perioperative data were reviewed, including age, sex, operative time, anesthesia time, blood loss, chest tube duration, hospital stay, postoperative recovery days, complications, and 30-day mortality. The trial was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Institutional Review Board of the Eunpyeong St. Mary’s Hospital, College of Medicine, The Catholic University of Korea (No. PC25RASI0133), and informed consent was taken from all the patients.

Institutional protocol for lung cancer resection

Segmentectomy was the preferred approach for patients with early-stage NSCLC meeting predefined oncologic criteria: (I) peripheral tumor ≤2.0 cm on computed tomography (CT), (II) SUV_max ≤3.0 on fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT), (III) anticipated resection surgical margin ≥2.0 cm or exceeding tumor size, and (IV) absence of N1 metastasis on intraoperative frozen biopsy. Patients not meeting all criteria underwent lobectomy. Lobe-specific or systematic lymph node dissection was performed based on tumor characteristics. All surgeries were conducted via uniportal VATS.

Perioperative management

Postoperative chest drainage was managed using a digital drainage system (Thopaz^®, Medela Healthcare), initially set to 15 cmH₂O and reduced to 7 cmH₂O on postoperative day 1. Chest tubes were removed when air leakage ceased for >12 hours and drainage volume was <200 mL/day. Patients were discharged the day after chest tube removal if clinically stable and logistically feasible.

Statistical analysis

All statistical analyses were conducted using R software (R Foundation for Statistical Computing, Vienna, Austria). Categorical variables were compared using Fisher’s exact test or Pearson’s chi-squared test, and continuous variables were compared using the Wilcoxon rank-sum test. Data were expressed as means with ranges or counts with percentages, as appropriate. Subgroup comparisons between lobectomy and segmentectomy included age, sex distribution, operative time, anesthesia time, intraoperative blood loss, chest tube duration, hospital stay, postoperative recovery days, complication rates, and 30-day mortality. Trends in surgical volume, operative time, and blood loss were visualized quarterly using line and bar charts. A P<0.05 was considered statistically significant.

Results

Between June 2022 and June 2025, a total of 402 thoracic operations were performed by the junior surgeon. Of these, 123 were major pulmonary resections, including 75 lobectomies and 48 segmentectomies. The number of major resections increased steadily over the study period, with only two procedures in 2023, followed by 71 in 2024 and 50 in the first half of 2025. Notably, the proportion of segmentectomies increased from 0 in 2023 to 48% by the second quarter of 2025, reflecting growing technical confidence and alignment with current oncologic criteria for sublobar resections (Table 1).

Operative performance improved significantly over time. The average operative time for major pulmonary resections decreased from 207.5 minutes in 2023 to 152.6 minutes in 2025. A parallel trend was observed for anesthesia duration, which declined from 241.0 to 163.5 minutes over the same period. These improvements were observed in the context of a steadily rising surgical volume and case complexity (Figures 1,2). Additionally, intraoperative blood loss progressively decreased, with the mean volume falling from over 200 mL in early cases to approximately 80 mL in later quarters (Figure 3).

Figure 1 Cumulative surgical case volume by quarter, including all surgeries and major pulmonary resections.

Figure 2 Quarterly average operative time for major pulmonary resections.

Figure 3 Quarterly average blood loss in major pulmonary resections, with case volume annotations. “n” indicates the number of major pulmonary resections performed each quarter.

A subgroup analysis comparing lobectomy and segmentectomy revealed several statistically significant differences in operative and perioperative outcomes (Table 2). Segmentectomy cases were associated with shorter operative times (139.8 vs. 175.0 minutes, P<0.001), reduced anesthesia durations (167.1 vs. 206.1 minutes, P<0.001), lower estimated blood loss (42.1 vs. 94.1 mL, P=0.001), and shorter durations of chest tube drainage (1.7 vs. 2.9 days, P<0.001). Furthermore, patients who underwent segmentectomy experienced shorter hospital stays (7.0 vs. 10.3 days, P=0.02) and faster postoperative recovery (3.9 vs. 6.5 days, P=0.01).

No significant differences were noted in complication rates (12.5% for segmentectomy vs. 16.0% for lobectomy, P=0.79) or 30-day mortality rates (0.0 vs. 1.3%, P>0.99). The single mortality case occurred in late 2023, attributed to acute respiratory distress syndrome (ARDS) secondary to pulmonary hemorrhage related to anticoagulation therapy more than one month postoperatively, and was not considered surgery-related.

These findings demonstrate a steep but favorable learning curve in major pulmonary resections during the surgeon’s first three years of independent practice. The progression was marked by improved surgical efficiency, increased case complexity, and adherence to institutional protocols guiding the selection of segmentectomy versus lobectomy.

CUSUM analysis of lung cancer cases requiring major pulmonary resections further delineated procedure-specific learning curves (Figure 4). For segmentectomy, the turning point was observed at the 16th case, with mean operative time decreasing from 151.8 minutes during the first 16 cases to 132.7 minutes in the subsequent 27 cases, representing a reduction of approximately 19.1 minutes. In contrast, lobectomy demonstrated its turning point later, at the 26th case, with mean operative time decreasing from 182.3 minutes (first 26 cases) to 164.7 minutes (subsequent 43 cases), corresponding to a 17.6-minute reduction. These trends illustrate earlier stabilization of operative efficiency for segmentectomy compared with lobectomy, which may reflect the effect of frequent exposure to segmentectomy at our institution, combined with structured training.

Figure 4 CUSUM analysis of operative time for lobectomy and segmentectomy in lung cancer patients. The curves demonstrate learning patterns with respective turning and stabilization points (segmentectomy, red and blue dashed lines; lobectomy, orange and green dashed lines). CUSUM, cumulative sum.

Discussion

This study delineates the early learning curve of a junior thoracic surgeon, demonstrating that structured assistantship, progressive case complexity, and systematic case selection can facilitate safe and efficient major pulmonary resections, including anatomical segmentectomy, during the first three years of independent practice. Prior reports suggest that proficiency in VATS lobectomy typically requires 50–60 cases, with learning curves influenced by prior minor VATS experience, institutional volume, and supervision (1,7). In our cohort, however, significant improvements in operative time and intraoperative blood loss were observed before reaching this threshold, likely attributable not only to extensive prior exposure as a high-volume assistant but also to continuous intraoperative guidance. CUSUM analysis of lobectomy cases revealed a turning point at the 26th operation, with mean operative time decreasing from 182.3 minutes in the first 26 cases to 164.7 minutes in the subsequent 43 cases, reflecting a reduction of 17.6 minutes. This finding aligns with previous reports that lobectomy requires a relatively longer adaptation period, but it also demonstrates that structured assistantship, intraoperative mentorship, and progressive case allocation can facilitate measurable improvements in operative efficiency even before the traditionally cited threshold of 50–60 cases. These results suggest that systematic training pathways can help junior surgeons achieve proficiency in lobectomy earlier than expected. Importantly, during the assistantship, the mentor surgeon actively shared procedural tips, nuanced decision-making processes, and personal experiences, providing the junior surgeon with context-specific strategies and tacit knowledge that complemented hands-on experience.

The increasing proportion of segmentectomies reflects the global shift toward lung parenchyma-sparing strategies for early-stage NSCLC. Recent randomized controlled trials, including JCOG0802/WJOG4607L and CALGB/Alliance 140503, have confirmed segmentectomy as an oncologically valid alternative to lobectomy for small peripheral tumors (3,4). Nonetheless, anatomical segmentectomy remains technically demanding, requiring meticulous preoperative planning, mastery of segmental anatomy, and advanced thoracoscopic skills (5).

Interestingly, our CUSUM analysis demonstrated that segmentectomy reached a turning point earlier (16th case) than lobectomy (26th case), with mean operative times decreasing by 19.1 and 17.6 minutes, respectively, after these thresholds. Despite the greater technical complexity of anatomical segmentectomy, proficiency appeared to be achieved more rapidly. This may reflect the surgeon’s frequent exposure to segmentectomy at our institution and the use of cognitive preparation strategies such as video review and mental rehearsal. Notably, this earlier turning point highlights that proficiency in segmentectomy may be achievable with fewer cases than traditionally expected, particularly when supported by structured mentorship and frequent institutional exposure.

Consistent with these findings, a previous study by the senior mentor of this work reported that surgeons with sufficient prior experience in major pulmonary resections faced minimal or significantly shortened learning curves when transitioning to complex segmentectomy (10). Extending from both our CUSUM results and prior reports, the junior surgeon in our study progressed through a structured training pathway—starting with assistantship and independent performance of minor thoracic procedures, advancing to lobectomy, and subsequently incorporating complex segmentectomies. Supporting this approach, recent studies on the uniportal segmentectomy learning curve have demonstrated that prior lobectomy experience substantially reduces the technical adaptation period. For instance, Matsuura et al. reported that with experienced supervision, initial proficiency in uniportal segmentectomy was achieved after approximately 60 cases, with faster mastery observed among surgeons with prior VATS lobectomy background (11). Similarly, Chen et al. found that prior lobectomy experience facilitated technical mastery in segmentectomy after around 58–63 cases (12). The earlier stabilization observed in our study suggests that structured mentorship, frequent institutional exposure to segmentectomy, and deliberate cognitive rehearsal may substantially shorten this technical adaptation period compared with prior reports.

Beyond hands-on experience, this study underscores the value of observational learning and cognitive rehearsal. The junior surgeon actively reviewed surgical videos and engaged in mental rehearsal, particularly before unfamiliar procedures. This aligns with evidence showing that cognitive strategies, such as mental imagery and simulation, enhance learning efficiency and technical performance (13,14).

These approaches are particularly relevant in the Republic of Korea surgical environment, where recent legal changes, such as the September 2023 mandatory closed-circuit television (CCTV) installation law, have heightened medico-legal scrutiny (15). Under these conditions, supervising surgeons may be increasingly hesitant to delegate operative responsibility to junior surgeons, limiting opportunities for direct operative experience and making structured mentorship and cognitive preparation even more essential for overcoming the early learning curve.

Importantly, our study showed low complication and mortality rates, which may reflect not only the surgeon’s technical progression but also the contribution of a well-established perioperative care system. Similar to reports showing that high-volume VATS centers achieve lower complication rates, our findings suggest that even early-career surgeons can maintain safe outcomes when supported by systematically structured perioperative care pathways and discharge protocols (16).

This study has several limitations. First, it is a single-surgeon, single-institution retrospective analysis, which may limit generalizability. The observed learning curve and perioperative outcomes may have been strongly influenced by institutional factors such as the availability of structured mentorship, well-established perioperative protocols, and a high case volume of minimally invasive pulmonary resections. Moreover, the junior surgeon’s extensive prior exposure as a high-volume assistant likely accelerated technical adaptation, and such experiences may not be uniformly available across training environments. Therefore, caution should be exercised when extrapolating these findings to broader populations of early-career thoracic surgeons practicing under different mentorship quality, institutional support systems, or training resources. Second, oncologic outcomes such as recurrence-free or overall survival could not be fully evaluated due to the limited follow-up period. Third, case selection was guided by institutional protocols, introducing a potential selection bias, particularly in comparing lobectomy and segmentectomy groups. Finally, although we performed a CUSUM analysis to identify procedure-specific turning points, additional approaches such as time-series modeling or multi-surgeon validation may provide further insights.

Conclusions

In conclusion, this study demonstrates that a structured, stepwise training approach—combining assistantship, gradual case complexity, and cognitive preparation—can enable junior thoracic surgeons to safely acquire major pulmonary resection skills, including complex segmentectomy, early in independent practice. Prior lobectomy experience, active mentorship, and self-directed learning were key factors in overcoming technical challenges. Additionally, a well-established perioperative care system likely contributed to the low complication and mortality rates observed.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1432/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1432/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1432/prf

Funding: None.

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1432/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The trial was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Institutional Review Board of the Eunpyeong St. Mary’s Hospital, College of Medicine, The Catholic University of Korea (No. PC25RASI0133), and informed consent was taken from all the patients.

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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