Abstract
Objective
To evaluate the influence of surgeon experience on outcomes in early-stage non-small cell lung cancer (NSCLC).
Methods
In an institutional database patients undergoing operations for pathologic stage I NSCLC by surgeons within 5 years of completion of training were categorized as low experience (LE), 5–15 years of experience as moderate experience (ME), and >15 years as high experience (HE) groups.
Results
From 2000–2012, eight hundred operations (638 lobectomies, 163 sublobar resection) were performed with the following distribution: LE 178 (22.2%), ME 224 (28.0%), HE 398 (49.8%). The groups were similar in age and comorbidities. The utilization of VATS was higher in the ME group [LE: 62/178 (34.8%), ME: 151/224 (67.4%), HE: 133/398 (33.4%), p <0.001] as was the mean number of mediastinal (N2) lymph node stations sampled (LE: 2.8±1.6, ME: 3.5±1.7, HE: 2.3±1.4, p<0.001).
The risk of perioperative morbidity was similar across all groups [LE: 54/178 (30.3%), ME: 51/224 (22.8%), HE: 115/398 (28.9%), p=0.163]. Five-year overall survival in the ME group was 76.9% compared to 67.5% in the LE group (p<0.001) and 71.4% in the HE group (p=0.006). In a Cox proportional hazard model, increasing age, male gender, prior cancer, and R1 resection were associated with an elevated risk of mortality, while being operated on by ME surgeons, and a greater number of mediastinal (N2) lymph node stations sampled were protective.
Conclusions
The experience of the surgeon does not impact perioperative outcomes after resection for pathologic stage I NSCLC. At least moderate experience after fellowship is associated with improved long-term survival.
Introduction
Surgical and institutional factors appear to influence morbidity and mortality in resection for esophageal, pancreas, colon and lung cancers. (1–11) Several authors have studied surgeon-and hospital volumes as well as surgeon specialization as possible influential variables, with some reports demonstrating decreased mortality with higher surgical volume and greater degree of surgeon specialization. (6, 8, 11) This is particularly true in surgery for early-stage non-small cell lung cancer (NSCLC). (2, 10–13)
However, previous studies evaluating impact of the individual surgeon on outcomes in lung cancer have focused mainly on thoracic surgical specialization and surgical volume. (10–14) The role of increasing surgical experience over time as an independent practitioner remains largely unknown. Additionally, these studies have largely reported on postoperative mortality, with considerably less attention to perioperative morbidity. (4, 10, 11) Since postoperative morbidity is much more common than mortality after pulmonary resection (20–40 % vs. 1–3 %) (12, 15), the impact of the individual surgeon on early postoperative outcomes remains inadequately understood.
We evaluated the impact of surgeon experience accrued after cardiothoracic surgery fellowship training on the morbidity and mortality of patients undergoing curative resection for pathologic stage I non-small cell lung cancer. We hypothesized that patients undergoing operations by less experienced surgeons would demonstrate increased perioperative morbidity and long-term mortality.
Patients and Methods
With institutional review board approval, a single-center, retrospective review of a prospectively maintained lung cancer database was performed. Inclusion criteria were patients who underwent initial resection by lobectomy or sub-lobar resection for resection of pathologic stage I NSCLC lung cancer and operation performed between January, 2000 and December, 2012 at Washington University School of Medicine. Only pathologic stage I was included to ensure a uniform population to prevent confounding from upstaging and downstaging. We chose a start date of 2000 for this study since electronic patient records first became available for review at the time. Exclusion criteria included pneumonectomies, operations for recurrent cancer, resections involving multi-lobes, and operations for subsequent primary cancers in patients who had undergone a prior lung resection.
Surgical experience was determined based on the number of years after the completion of a cardiothoracic surgery fellowship for the operating surgeon at the time of surgery. Operations conducted within the first 5 years of practice after specialty training for the surgeon were classified as the low experience group (LE); those performed by surgeons with 5 to ≤15 years of experience as the moderate experience group (ME), while the high experience group (HE) included operations performed by surgeons with more than 15 years of post-fellowship experience. Thus cases performed by a single surgeon could be in different groups depending on when a particular operation was performed in that surgeon’s post-fellowship career.
We abstracted details of patient demographics, diagnosis, workup, operation, perioperative course, and outcomes from the institutional database. Missing data were obtained by review of patient charts. Perioperative events were defined per the Society of Thoracic Surgeons (STS) data collection guidelines. (16) Patient survival was determined from clinic notes and supplemented by querying the social security death index.
Statistics
Data was managed with Microsoft Excel and analyzed using SPSS 21.0 for Windows (SPSS Inc., Chicago, IL). Descriptive statistics were expressed as mean ± standard deviation unless otherwise specified. Categorical data were expressed as counts and percentages. Comparisons between normally distributed continuous variables were performed with one-way ANOVA or the t-test and differences among the categorical data were analyzed with chi-square test. Post-hoc analyses for pairwise comparisons were performed using the Bonferroni method for categorical data and the Tukey method for continuous variables. Kaplan-Meier survival plots were generated and groups were compared using the log-rank test. P values less than 0.05 were considered statistically significant. For pairwise comparisons using the Bonferroni method, a P value less than 0.017 was considered significant. A Cox proportional hazard model was then fitted to determine variables that impacted the risk of long-term mortality. For this model we considered age, gender, smoking status, coronary artery disease (CAD), hypertension (HTN), forced expiratory volume in 1 second percent (FEV1%), diffusing capacity of carbon monoxide percent (DLCO%), body mass index (BMI), prior cancer, surgeon experience, procedure (lobectomy vs. sublobar resection), adequacy of resection (negative margins), number of mediastinal (N2) lymph node stations sampled, and type of incision (VATS vs. thoracotomy) as independent variables.
After an initial exploratory analysis of all pathologic stage I lung cancer patients who underwent resection, we dichotomized patients into a lobectomy group and a sublobar resection group. Identical analyses as described above were performed in these groups. We also performed a subgroup analysis to determine if there was an impact of accrued experience for each individual surgeon.
For those surgeons who began operating during the study period, their first 25 operations were compared to their subsequent 25 operations with a comparison of both preoperative variables and outcomes.
Results
Between January 2000 and December 2012, eight hundred patients underwent resection for pathologic stage I lung cancer by 8 surgeons. Of these operations, 178 (22.2%) resections were in the LE group (< 5 years’ experience for operating surgeon), 224 (28.0%) in the ME group (5 to ≤15 years’ experience for surgeon), and 398 (49.8%) in the HE group (>15 years’ experience for surgeon). Operations were performed by 6 different surgeons in the LE group, 5 surgeons in the ME group, and 2 surgeons in the HE group. Patients in the three groups were similar in age and distribution of comorbidities (Table 1). The LE group comprised of a higher proportion of males and non-white patients than the HE group. (Table 1)
Table 1.
Patient demographics and comorbidities for all resections (lobectomy and sub-lobar resection)
| Variable | LE (n=178) | ME (n=224) | HE (n=398) | P | |
|---|---|---|---|---|---|
| Mean Age (years) | 64.6 ± 11.4 | 64.3 ± 10.5 | 65.5 ± 11.4 | 0.365 | |
| Male Gender | 95(53.4%) | 104(46.4%) | 162(44.9%) | 0.017* | |
| Non-White Race | 38(21.3%) | 30(13.4%) | 42(10.6%) | 0.002# | |
| Smoking Status | 0.144 | ||||
| Never | 14(7.9%) | 30(13.4%) | 52(13.1%) | ||
| Past | 91(51.1%) | 112(50.0%) | 218(54.8%) | ||
| Current | 73(41.0%) | 82(36.6%) | 128(32.2%) | ||
| Prior stroke | 11(6.2%) | 12(5.4%) | 27(6.8%) | 0.779 | |
| Coronary Artery Disease | 40(22.5%) | 34(15.2%) | 81(20.4%) | 0.145 | |
| Hypertension | 103(57.9%) | 120(53.6%) | 216(54.3%) | 0.652 | |
| Congestive Heart Failure | 3(1.7%) | 2(0.9%) | 8(2.0%) | 0.570 | |
| Peripheral Vascular Disease | 10(5.6%) | 7(3.1%) | 18(4.5%) | 0.469 | |
| Baseline FEV1 % predicted | 79.7 ± 21.1 | 80.9 ± 19.9 | 79.3 ± 22.1 | 0.656 | |
| Baseline DLCO% predicted | 70.8 ± 21.6 | 72.7 ± 20.6 | 71.4 ± 21.6 | 0.642 | |
| Body Mass Index | 27.1 ± 5.8 | 27.2 ± 5.9 | 26.9 ± 6.2 | 0.827 | |
| Prior Cancer | 69(38.8%) | 77(34.4%) | 134(33.7%) | 0.483 | |
| Clinical Stage | 0.666 | ||||
| I | 159(89.3%) | 207(92.4%) | 368(92.5%) | ||
| II | 9(5.1%) | 7(3.1%) | 16(4.0%) | ||
| III | 10(5.6%) | 10(4.5%) | 14(3.5%) | ||
LE versus ME p= 0.167, LE versus HE p= 0.005, ME versus HE p = 0.166
LE versus ME p= 0.047, LE versus HE p= 0.001, ME versus HE p = 0.222
LE = low experience, ME = moderate experience, HE = high experience, FEV1 = forced expiratory volume in 1 second, DLCO = carbon dioxide diffusing capacity
Of the 800 operations, there were 638 (79.8%) lobectomies and 162 (20.2%) sublobar resections. The LE group patients were more likely to undergo lobectomies as opposed to sublobar resections [LE 157/178 (88.2%)] compared to the ME [176/224 (78.6%), p=0.011], and HE [305/398 (76.6%), p = 0.001] patients. The utilization of video assisted thoracoscopy (VATS) was higher in the ME group than the other 2 groups [LE: 62/178 (34.8%), ME: 151/224 (67.4%), HE: 133/398 (33.4%), all p <0.001]. Since VATS was more widely adopted in our program around 2007–08, we performed a subgroup analysis considering operations performed after January 2008. ME group patients were still more likely to undergo VATS operations [133/160, (83.1%)] compared to LE patients [49/79 (62.0%), p<0.001] but were similar to the HE group [129/177(72.9%), p=0.024, not significant with Bonferroni correction] The number of microscopically incomplete resections (R1 resections) was similar across all groups [LE: 5/178 (2.8%), ME: 7/224 (3.1%), HE: 10/398 (2.5%), p=0.903]. The mean number of mediastinal (N2) lymph node stations sampled per operation was highest for the ME group and lowest for the HE group (LE: 2.8±1.6, ME: 3.5±1.7, HE: 2.3±1.4, p<0.001, LE vs. ME p<0.001, LE vs. HE p=0.001, ME vs. HE p<0.001).
The risk of any perioperative morbidity defined per STS criteria was similar across all groups [LE: 54/178 (30.3%), ME: 51/224 (22.8%), HE: 115/398 (28.9%), p=0.163]. The risk of specific complications was also similar across the groups. (Table 2) There were no differences in length of hospital stay or perioperative mortality between the groups. Unadjusted five-year overall survival in the ME group was 76.9% compared to 67.5% in the LE group (p<0.001) and 71.4% in the HE group (p=0.006). (Figure 1A)
Table 2.
Comparison of perioperative outcomes between the three groups for all resections (lobectomy and sub-lobar resection).
| Variable | LE (n=178) | ME (n=224) | HE (n=398) | P |
|---|---|---|---|---|
| Prolonged Air Leak | 13(7.3%) | 8(3.6%) | 33(8.3%) | 0.075 |
| Pneumonia | 11(6.2%) | 10(4.5%) | 21(5.3%) | 0.745 |
| Bronchopleural Fistula | 0(0.0%) | 1(0.4%) | 2(0.5%) | 0.646 |
| Blood Transfusion | 4(2.2%) | 1(0.4%) | 4(1.0%) | 0.224 |
| Empyema | 2(1.1%) | 1(0.4%) | 0(0.0%) | 0.123 |
| Respiratory Failure | 11(6.2%) | 7(3.1%) | 25(6.3%) | 0.212 |
| Dysrhythmia | 24(13.5%) | 24(10.7%) | 50(12.6%) | 0.677 |
| Deep Vein Thrombosis | 4(2.2%) | 3(1.3%) | 5(1.3%) | 0.647 |
| Renal Failure | 2(1.1%) | 1(0.4%) | 4(1.0%) | 0.712 |
| Hemorrhage requiring reoperation | 2(1.1%) | 0(0.0%) | 4(1.0%) | 0.305 |
| Stroke | 0(0.0%) | 2(0.9%) | 2(0.5%) | 0.452 |
| Any perioperative morbidity | 54(30.3%) | 51(22.8%) | 115(28.9%) | 0.163 |
| Mean length of hospital stay | 6.6 ± 6.3 | 5.3 ± 4.8 | 5.8 ± 6.6 | 0.086 |
| Readmission within 30 days | 13(7.3%) | 11(4.9%) | 32(8.0%) | 0.335 |
| 30 day/hospital mortality | 2(1.1%) | 0(0.0%) | 6(1.5%) | 0.190 |
LE = low experience, ME = moderate experience, HE = high experience
Figure 1.
A. Kaplan Meier overall survival for all resections (lobectomy & sub-lobar).
B. Kaplan Meier overall survival for patients undergoing lobectomy only.
During the study period, 638 patients underwent lobectomy for pathologic stage I lung cancer. Of these 157 (24.6%) were in the LE group, 176 (27.6%) in the ME group, and 305 (47.8%) in the HE group. Again, the LE group comprised a higher proportion of males and non-white patients than the HE group but not the ME group. (Online table 1) Considering operations performed from January 2008 onwards (since more widespread use of VATS), the ME and HE group patients were more likely to have operations via VATS compared to the LE group [LE 40/67(59.7%), ME 103/126 (81.7%), HE 87/123 (70.7%), overall p <0.001; LE vs. ME p = 0.001; ME vs. HE p = 0.041; LE vs. HE p = 0.123]. The proportion of R1 resections was similar across the 3 groups [LE: 3/157 (1.9%), ME: 6/176 (3.4%), HE: 5/305 (1.6%), p = 0.426]. The number of mediastinal (N2) lymph node stations sampled was again highest in the ME group and lowest in the HE group (LE: 3.0±1.5, ME: 3.8±1.5, HE: 2.5±1.5, overall p <0.001; LE vs. ME p<0.001; LE vs. HE p= 0.001; ME vs. HE p <0.001). Patients in the ME group had a lower incidence of prolonged postoperative air leak, while the remaining perioperative outcomes were similar across the groups. (Table 3) Five-year overall survival in the ME group was 80.7% compared to 70.5% in the LE group (p<0.001) and 73.6% in the HE group (p=0.006). (Figure 1B) In comparing data on each individual surgeon’s initial 25 and next 25 cases, no clear trends were seen.
Table 3.
Comparison of perioperative outcomes for patients undergoing lobectomy.
| Variable | LE (n=157) | ME (n=176) | HE (n=305) | P |
|---|---|---|---|---|
| Air Leak | 12(7.6%) | 5(2.8%) | 26(8.5%) | 0.050* |
| Pneumonia | 10(6.4%) | 9(5.1%) | 18(5.9%) | 0.882 |
| Bronchopleural Fistula | 0(0.0%) | 1(0.6%) | 2(0.7%) | 0.606 |
| Blood Transfusion | 4(2.5%) | 1(0.6%) | 4(1.3%) | 0.304 |
| Empyema | 2(1.3%) | 1(0.6%) | 0(0.0%) | 0.162 |
| Respiratory Failure | 11(7.0%) | 6(3.4%) | 23(7.5%) | 0.180 |
| Dysrhythmia | 23(14.6%) | 24(13.6%) | 44(14.4%) | 0.960 |
| Deep Vein Thrombosis | 4(2.5%) | 3(1.7%) | 2(0.7%) | 0.244 |
| Renal Failure | 2(1.3%) | 1(0.6%) | 3(1.0%) | 0.796 |
| Hemorrhage requiring reoperation | 2(1.3%) | 0(0.0%) | 3(1.0%) | 0.362 |
| Stroke | 0(0.0%) | 1(0.6%) | 1(0.3%) | 0.650 |
| Any perioperative morbidity | 50(31.8%) | 46(26.1%) | 92(30.2%) | 0.487 |
| Mean length of hospital stay | 6.96 ± 6.63 | 5.55 ± 4.34 | 6.24 ± 7.15 | 0.128 |
| Readmission within 30 days | 13(8.3%) | 10(5.7%) | 26(8.5%) | 0.502 |
| 30 day/hospital mortality | 2(1.3%) | 0(0.0%) | 5(1.6%) | 0.244 |
LE versus ME p= 0.047 (statistically not significant after adjustment for subgroup analysis), LE versus HE p= 0.744, ME versus HE p = 0.014 (statistically significant).
LE = low experience, ME = moderate experience, HE = high experience
In the Cox proportional hazard model evaluating the entire cohort (lobectomy and sublobar resections) increasing age, male gender, prior cancer, and R1 resection were associated with an elevated risk of mortality. Belonging to the ME group and a greater number of mediastinal (N2) lymph node stations sampled were associated with lower hazard of long-term mortality. (Table 4) In a subgroup analysis, identical results were seen for patients undergoing lobectomy. (Data not shown)
Table 4.
Cox proportional hazard model for overall survival in entire cohort of patients undergoing lobectomy or sub-lobar resection.
| Variable | Hazard Ratio (HR) |
95% Confidence Interval | |
|---|---|---|---|
| Surgeon experience included | |||
| Age | 1.05 | 1.03– 1.06 | |
| Gender (Male) | 1.48 | 1.13–1.94 | |
| Race (non-white) | 1.24 | 0.87–1.77 | |
| Smoking Status (never) | Reference category | ||
| Smoking (Past) | 0.93 | 0.56–1.55 | |
| Smoking (Current) | 1.36 | 0.80–2.31 | |
| Coronary Artery Disease | 1.20 | 0.89–1.61 | |
| Hypertension | 1.13 | 0.86–1.48 | |
| Baseline FEV1% predicted (scaled) | 0.87 | 0.72–1.05 | |
| Baseline DLCO% predicted (scaled) | 0.88 | 0.75–1.02 | |
| Body mass index | 0.98 | 0.95–1.01 | |
| Prior Cancer | 1.33 | 1.02–1.72 | |
| Experience (<5 yrs) | Reference category | ||
| Experience (5–15 yrs) | 0.52 | 0.34–0.80 | |
| Experience (>15 yrs) | 0.77 | 0.58–1.03 | |
| Sub-lobar resection | 0.98 | 0.70–1.38 | |
| Thoracoscopic approach | 0.89 | 0.64–1.22 | |
| Number of Mediastinal (N2) Lymph Node Stations Sampled | 0.90 | 0.82–0.98 | |
| R1 resection | 2.55 | 1.28–5.10 | |
| Surgeon experience not included | |||
| Age | 1.05 | 1.03– 1.06 | |
| Gender (Male) | 1.48 | 1.13–1.94 | |
| Race (non-white) | 1.30 | 0.912–1.86 | |
| Smoking Status (never) | Reference category | ||
| Smoking (Past) | 0.97 | 0.58–1.61 | |
| Smoking (Current) | 1.39 | 0.82–2.36 | |
| Coronary Artery Disease | 1.20 | 0.89–1.62 | |
| Hypertension | 1.11 | 0.85–1.46 | |
| Baseline FEV1% predicted scaled | 0.88 | 0.73–1.06 | |
| Baseline DLCO% predicted scaled | 0.86 | 0.74–1.01 | |
| Body mass index | 0.98 | 0.95–1.01 | |
| Prior Cancer | 1.33 | 1.02–1.72 | |
| Sub-lobar resection | 0.93 | 0.67–1.31 | |
| Thoracoscopic approach | 0.83 | 0.60–1.14 | |
| Number of Mediastinal (N2) Lymph Node Stations Sampled | 0.89 | 0.82–0.97 | |
| R1 resection | 2.57 | 1.29–5.12 | |
LE = low experience, ME = moderate experience, HE = high experience, FEV1 = forced expiratory volume in 1 second, DLCO = carbon dioxide diffusing capacity
We need to explain how the FEV1 and DLVO have been rescaled in this area.
Comment
Our main findings in this study are that experience after fellowship training does not impact short-term outcomes after resection for lung cancer. However, surgeons with at least moderate experience have a higher utilization of minimally invasive techniques and possibly improved long-term survival.
Currently, most statistical models use a variety of patient- and disease-specific variables such as age, pulmonary function, comorbidity scores, and pathologic stage to predict short-and long-term outcomes after pulmonary resection. (16–20) Additionally a number of studies have explored the role of surgeon specialty training, hospital case volume, and surgeon case volume in perioperative morbidity and long-term survival after surgery for lung cancer, however the results have been inconsistent. (2, 4, 10–14) These studies have largely utilized administrative databases and pooled information from multiple centers to conduct the analyses. This strategy, while providing a robust sample size in most cases, cannot account for variations in practice patterns across surgeons and institutions, both in the intraoperative as well as the postoperative care of patients. Thus, we explored the impact of the individual surgeon’s experience as a possible determinant of outcomes in a setting where all the surgeons are specialty trained, have been trained in the same setting, and employ uniform perioperative management protocols.
In one of the first studies of its kind in lung cancer, Bach et al evaluated the volume of lung resections at individual centers and found an inverse relationship between volume and postoperative complications. (13) They also noted improved long-term survival at higher-volume hospitals. Subsequently, Goodney et al analyzed the national Medicare database and noted that perioperative mortality was lower for specialty trained thoracic surgeons compared to others after adjusting for hospital volumes. (2) They considered >20 cases per year to indicate a high volume surgeon. By these criteria, all the operators involved in our study are specialty trained in thoracic surgery, and are high-volume surgeons. Other authors, including those from Europe and Asia, have also investigated the volume-outcomes relationship with mixed results. Sioris et al noted no effect of hospital volume on outcomes but university hospitals performed better than community hospitals. (10) Lien et al studied a population from Taiwan and reported lower in-hospital mortality with increasing individual surgeon volume of resections. Reviews have raised questions about the methodologic quality of studies in the field, and Kowtower felt that “careful examination of the literature demonstrates that lung cancer resection volume is not strongly associated with mortality and should not be used as a proxy measure for quality”. (14) Finally, in a meta-analysis von Meyenfeldt and colleagues pooled data from 19 studies and concluded the while hospital volume and surgeon specialty are determinants of outcome, individual surgeon volume is not important. (11)
Our study focused on measuring the impact of the experience of a surgeon measured in number of years in practice after completing cardiothoracic surgical fellowship training. Though this approach is novel to lung cancer surgery, it has been used in evaluating other cancer operations. (3, 21) It has been previously shown that despite existing evidence-based guidelines, decision-making in surgery continues to be strongly affected by anecdotal experience. (22)
We did not find a significant difference in perioperative morbidity or mortality with varying surgeon experience. Except for relatively minor differences in demographics, the patients across the 3 groups were similar in comorbidity. All except 1 surgeon in the group have been trained by the senior-most surgeon in this cohort and have fairly similar patterns of practice, both in patient selection and operative procedures. These factors can likely explain the consistent perioperative outcomes across groups. Previous studies evaluating perioperative outcomes have largely focused on mortality (2, 4, 11) and those studying postoperative morbidity and the surgical volume have not evaluated the individual surgeon’s impact on outcomes. (13)
Adequate lymph node sampling/dissection is one the cornerstones in lung cancer surgery. Previously, others have demonstrated improved patient outcomes in node negative NSCLC with greater number of lymph nodes sampled. (23–25) Our use of number of lymph node stations sampled was driven by the data available to us in our database, and has been recognized by other authors as a surrogate for number of lymph nodes resected. (25) We noted that the ME group tended to have a higher yield of lymph nodes and this also correlated with survival. It is plausible that surgeons who are in the early phase of their careers may be completely focused on “getting the specimen out” with less attention being paid to nodal sampling with its added operative time and perceived additional morbidity. Highly experienced surgeons may have a lower lymph node yield as the importance of nodal sampling has been predominantly realized over the last 2 decades, and these surgeons may have completed training in an earlier time period. It is also plausible that there may be higher degree of trainee involvement with HE surgeons and some parts of the operation (including lymph node assessment) may be performed independently by the residents. Regardless, our finding points towards the need for continued attention towards highlighting the importance of adequate nodal assessment.
We noted that patients operated on by ME surgeons had a somewhat longer overall survival compared to the other two groups. This correlated with better mediastinal lymph node assessment by the ME surgeons, a factor that has been associated with improved survival in previous publications. (23–25) Additionally, there was a higher likelihood for utilization of VATS techniques in the ME group. Others have reported improved long-term survival after VATS lobectomy (compared to open thoracotomy) in systematic reviews and meta-analyses of studies involving patients with clinical stage I NSCLC. (26, 27) The other variables noted to be associated with diminished survival, namely, increasing age, male gender, and incomplete resection, are well-established predictors for poorer long-term survival in lung cancer. (16, 18)
There are certain limitations to our study. Its retrospective nature introduces the possibility of selection bias. With patients from a single center, a limited sample size may lead to type II error where true differences between groups may be missed. We had 8 surgeons in the group, largely similarly trained, thus it may limit the generalizability of our findings. Lastly, intraoperative decision making is subjective and perioperative management varies, which could lead to misclassification bias. In order to limit such misclassification, we utilized STS guidelines for classifying perioperative adverse events and when in doubt on chart review, an event was classified as positive.
In conclusion, our study demonstrated that surgeon experience does not affect early perioperative outcomes after resection for early-stage lung cancer. However, patients operated on by moderately experienced surgeons may have better long-term survival after resection for pathologic stage I lung cancer. Expanding this study to a larger patient and surgeon population would be needed to validate the results and identify the underlying causes for these differences in order to provide the best patient care.
Supplementary Material
Acknowledgments
Grant support
Varun Puri -NIH K07CA178120, K12CA167540-02 (Paul Calabresi award)
Footnotes
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Presented at the 40th Annual Meeting of the Western Thoracic Surgical Association, Dana Point, California. June 28, 2014.
There are no conflicts of interest.
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