Node Doubt: Rigorous Surgical Nodal Procurement Combined With Thorough Pathologic Evaluation Improves Non-Small Cell Lung Carcinoma Staging Accuracy

Comparative validation of nodal classifications in resected non-small cell lung cancer based on the anatomical location and number of involved stations

INTRODUCTION

Nodal staging of non-small cell lung cancer (NSCLC) is important for treatment decision-making. Comparative validation of various classifications based on anatomical location and station count, alone or in combination, remains lacking.

METHODS

We analyzed 1,601 patients with pathological stage I-III disease undergoing complete resection between 2002 and 2019. Nodal classifications were based on "TNM 8th," "the International Association for the Study of Lung Cancer (IASLC) exploratory proposal in TNM 8th," "TNM 9th," and "the number of involved nodal stations/zones." The ability of each classification to predict recurrence-free survival was examined using multivariate Cox regression analysis and time-dependent receiver operating characteristic (ROC) curves. Agreement between clinical and pathological nodal staging (cN and pN) was also assessed.

RESULTS

The IASLC exploratory proposal classification in TNM 8th revealed a better prognosis (P < 0.05) for single-station skip N2 within the N2 group, overlapping with N1. Other classifications stratified N descriptors into prognostically distinct subgroups, with time-dependent ROC curves showing no clinically significant differences between the classifications. However, N descriptors based on the number of involved stations/zones formed distinct prognostic subgroups when further stratified by anatomical location. cN and pN agreement was generally low for N1 (44.7 %) and very low for N1 based on the number of involved stations (in the 20 % range).

CONCLUSIONS

Future revisions of NSCLC nodal staging should integrate anatomical location and the number of involved stations, as in TNM 9th. Moreover, N1 subclassification should be avoided, given the difficulty in counting cN1 stations. From a prognostic perspective, single-station skip N2 should be integrated with N1.

Two Interventions on Pathologic Nodal Staging in a Population-Based Lung Cancer Resection Cohort

BACKGROUND

Despite its prognostic importance, poor pathologic nodal staging of lung cancer prevails. We evaluated the impact of 2 interventions to improve pathologic nodal staging.

METHODS

We implemented a lymph node specimen collection kit to improve intraoperative lymph node collection (surgical intervention) and a novel gross dissection method for intrapulmonary node retrieval (pathology intervention) in nonrandomized stepped-wedge fashion, involving 12 hospitals and 7 pathology groups. We used standard statistical methods to compare surgical quality and survival of patients who had neither intervention (group 1), pathology intervention only (group 2), surgical intervention only (group 3), and both interventions (group 4).

RESULTS

Of 4019 patients from 2009 to 2021, 50%, 5%, 21%, and 24%, respectively, were in groups 1 to 4. Rates of nonexamination of lymph nodes were 11%, 9%, 0%, and 0% and rates of nonexamination of mediastinal lymph nodes were 29%, 35%, 2%, and 2%, respectively, in groups 1 to 4 (P < .0001). Rates of attainment of American College of Surgeons Operative Standard 5.8 were 22%, 29%, 72%, and 85%; and rates of International Association for the Study of Lung Cancer complete resection were 14%, 21%, 53%, and 61% (P < .0001). Compared with group 1, adjusted hazard ratios for death were as follows: group 2, 0.93 (95% CI, 0.76-1.15); group 3, 0.91 (0.78-1.03); and group 4, 0.75 (0.64-0.87). Compared with group 2, group 4 adjusted hazard ratio was 0.72 (0.57-0.91); compared with group 3, it was 0.83 (0.69-0.99). These relationships remained after exclusion of wedge resections.

CONCLUSIONS

Combining a lymph node collection kit with a novel gross dissection method significantly improved pathologic nodal evaluation and survival.

Influencing Factors on the Quality of Lymph Node Dissection for Stage IA Non-Small Cell Lung Cancer: A Retrospective Nationwide Cohort Study

Lymphadenectomy is an essential part of complete surgical operation for non-small cell lung cancer (NSCLC). This retrospective, multicenter cohort study aimed to identify factors that influence the lymphadenectomy quality. Data were obtained from the Polish Lung Cancer Study Group Database. The primary endpoint was lobe-specific mediastinal lymph node dissection (L-SMLND). The study included 4271 patients who underwent VATS lobectomy for stage IA NSCLC, operated between 2007 and 2022. L-SMLND was performed in 1190 patients (27.9%). The remaining 3081 patients (72.1%) did not meet the L-SMLND criteria. Multivariate logistic regression analysis showed that patients with PET-CT (OR 3.238, 95% CI: 2.315 to 4.529; p < 0.001), with larger tumors (pT1a vs. pT1b vs. pT1c) (OR 1.292; 95% CI: 1.009 to 1.653; p = 0.042), and those operated on by experienced surgeons (OR 1.959, 95% CI: 1.432 to 2.679; p < 0.001) had a higher probability of undergoing L-SMLND. The quality of lymphadenectomy decreased over time (OR 0.647, 95% CI: 0.474 to 0.884; p = 0.006). An analysis of propensity-matched groups showed that more extensive lymph node dissection was not related to in-hospital mortality, complication rates, and hospitalization duration. Actions are needed to improve the quality of lymphadenectomy for NSCLC.

Surgeon Quality and Patient Survival After Resection for Non-Small-Cell Lung Cancer

PURPOSE

The quality and outcomes of curative-intent lung cancer surgery vary in populations. Surgeons are key drivers of surgical quality. We examined the association between surgeon-level intermediate outcomes differences, patient survival differences, and potential mitigation by processes of care.

PATIENTS AND METHODS

Using a baseline population-based surgical resection cohort, we derived surgeon-level cut points for rates of positive margins, nonexamination of lymph nodes, nonexamination of mediastinal lymph nodes, and wedge resections. Applying the baseline cut points to a subsequent cohort from the same population-based data set, we assign surgeons into three performance categories in reference to each metric: 1 (<25th percentile), 2 (25th-75th percentile), and 3 (>75th percentile). The sum of performance scores created three surgeon quality tiers: 1 (4-6, low), 2 (7-9, intermediate), and 3 (10-12, high). We used chi-squared, Wilcoxon-Mann-Whitney, and Kruskal-Wallis tests to compare patient characteristics between the baseline and subsequent cohorts and across surgeon tiers. We applied Cox proportional hazards models to examine the association between patient survival and surgeon performance tier, sequentially adjusting for clinical stage, patient characteristics, and four specific processes.

RESULTS

From 2009 to 2021, 39 surgeons performed 4,082 resections across the baseline and subsequent cohorts. Among 31 subsequent cohort surgeons, five were tier 1, five were tier 2, and 21 were tier 3. Tier 1 and 2 surgeons had significantly worse outcomes than tier 3 surgeons (hazard ratio [HR], 1.37; 95% CI, 1.10 to 1.72 and 1.19; 95% CI, 1.00 to 1.43, respectively). Adjustment for specific processes mitigated the surgeon-tiered survival differences, with adjusted HRs of 1.02 (95% CI, 0.8 to 1.3) and 0.93 (95% CI, 0.7 to 1.25), respectively.

CONCLUSION

Readily accessible intermediate outcomes metrics can be used to stratify surgeon performance for targeted process improvement, potentially reducing patient survival disparities.

Institution-Level Evolution of Lung Cancer Resection Quality With Implementation of a Lymph Node Specimen Collection Kit

INTRODUCTION

Lung cancer surgery with a lymph node kit improves patient-level outcomes, but institution-level impact is unproven.

METHODS

Using an institutional stepped-wedge implementation study design, we compared lung cancer resection quality between institutions in preimplementation and postimplementation phases of kit deployment and, within implementing institutions, resections without versus with the kit. Benchmarks included rates of nonexamination of lymph nodes, nonexamination of mediastinal lymph nodes, and attainment of American College of Surgeons Operative Standard 5.8. We report institution-level adjusted ORs (aORs) for attaining quality benchmarks.

RESULTS

From 2009 to 2020, three preimplementing hospitals had 953 resections; 11 implementing hospitals had 4013 resections, 58% without and 42% with the kit. Quality was better in implementing institutions and with kit cases. Compared with preimplementing institutions, the aOR for nonexamination of lymph nodes was 0.62 (0.49-0.8, p = 0.002), nonexamination of mediastinal lymph nodes was 0.56 (0.47-0.68, p < 0.0001), and attainment of Operative Standard 5.8 was 7.3 (5.6-9.4, p < 0.0001); aORs for kit cases were 0.01 (0.001-0.06), 0.08 (0.06-0.11), and 11.6 (9.9-13.7), respectively (p < 0.0001 for all). Surgical quality was persistently poor in preimplementing institutions but sequentially improved in implementing institutions in parallel with kit adoption. In implementing institutions, resections with the kit had a uniformly high level of quality, whereas nonkit cases had a low level of quality, approximating that of preimplementing institutions. Within implementing institutions, 5-year overall survival was 61% versus 51% after surgery with versus without the kit (p < 0.001).

CONCLUSIONS

Surgery with a lymph node specimen collection kit improved institution-level quality of curative-intent lung cancer resection.

Identification of Factors Related to the Quality of Lymphadenectomy for Lung Cancer: Secondary Analysis of Prospective Randomized Trial Data

The outcomes of non-small cell lung cancer surgery are influenced by the quality of lymphadenectomy. This study aimed to evaluate the impact of different energy devices on lymphadenectomy quality and identify additional influencing factors. This secondary analysis of the prospective randomized trial data (clinicaltrials.gov: NCT03125798) compared patients who underwent thoracoscopic lobectomy with the LigaSure device (study group, n = 96) and monopolar device (control group, n = 94). The primary endpoint was the lobe-specific mediastinal lymphadenectomy. Lobe-specific mediastinal lymphadenectomy criteria were met in 60.4% and 38.3% of patients in the study and control groups, respectively (p = 0.002). In addition, in the study group, the median number of mediastinal lymph node stations removed was higher (4 vs. 3, p = 0.017), and complete resection was more often achieved (91.7% vs. 80.9%, p = 0.030). Logistic regression analysis indicated that lymphadenectomy quality was positively associated with the use of the LigaSure device (OR, 2.729; 95% CI, 1.446 to 5.152; p = 0.002) and female sex (OR, 2.012; 95% CI, 1.058 to 3.829; p = 0.033), but negatively associated with a higher Charlson Comorbidity Index (OR, 0.781; 95% CI, 0.620 to 0.986; p = 0.037), left lower lobectomy (OR, 0.263; 95% CI, 0.096 to 0.726; p = 0.010) and middle lobectomy (OR, 0.136; 95% CI, 0.031 to 0.606, p = 0.009). This study found that using the LigaSure device can improve the quality of lymphadenectomy in lung cancer patients and also identified other factors that affect the quality of lymphadenectomy. These findings contribute to improving lung cancer surgical treatment outcomes and provide valuable insights for clinical practice.

Survival After Mediastinal Node Dissection, Systematic Sampling, or Neither for Early Stage NSCLC

INTRODUCTION

The American College of Surgeons Oncology Group Z0030 found no survival difference between patients with early stage NSCLC who had mediastinal nodal dissection or systematic sampling. However, a meta-analysis of 1980 patients in five randomized controlled trials from 1989 to 2007 associated better survival with nodal dissection. We tested the survival impact of the extent of nodal dissection in curative-intent resections for early stage NSCLC in a population-based observational cohort.

METHODS

Resections for clinical T1 or T2, N0 or nonhilar N1, M0 NSCLC in four contiguous United States Hospital Referral Regions from 2009 to 2019 were categorized into mediastinal nodal dissection, systematic sampling, and "neither" on the basis of of the evaluation of lymph node stations. We compared demographic and clinical characteristics, perioperative complication rates, and survival after assessing statistical interactions and confounding.

RESULTS

Of the 1942 eligible patients, 18% had nodal dissection, 6% had systematic sampling, and 75% had an intraoperative nodal evaluation that met neither standard. In teaching hospitals, nodal dissection was associated with a lower hazard of death than "neither" resections (0.57 [95% confidence interval: 0.41-0.79]) but not systematic sampling (0.74 [0.40-1.37]) after adjusting for multiple comparisons. There was no significant difference in hazard ratios at nonteaching institutions (p > 0.3 for all comparisons). Perioperative complication rates were not significantly worse after mediastinal nodal dissection or systematic sampling, compared with "neither," (p > 0.1 for all comparisons).

CONCLUSIONS

In teaching institutions, mediastinal nodal dissection was associated with superior survival over less-comprehensive pathologic nodal staging. There was no survival difference between teaching and nonteaching institutions, a finding that warrants further investigation.

Beyond Margin Status: Population-Based Validation of the Proposed International Association for the Study of Lung Cancer Residual Tumor Classification Recategorization

INTRODUCTION

The International Association for the Study of Lung Cancer's (IASLC's) proposal to recategorize the residual tumor (R) classification for resected NSCLC needs validation.

METHODS

Using a 2009 to 2019 population-based multi-institutional NSCLC resection cohort from the United States, we classified resections by Union for International Cancer Control (UICC) and IASLC R criteria and compared the distribution of R classification variables and their survival associations.

RESULTS

Of 3361 resections, 95.3% were R0, 4.3% were R1, and 0.4% were R2 by UICC criteria; 33.3% were R0, 60.8% were R-uncertain, and 5.8% were R1/2 by IASLC criteria; 2044 patients (63.8%) migrated from UICC R0 to IASLC R-uncertain. Median survival was not reached, 69 (95% confidence interval [CI]: 64-77), and 25 (95% CI: 18-36) months, respectively, for patients with IASLC R0, R-uncertain, and R1 or R2 resections. Failure to achieve nodal dissection criteria caused 98% of migration to R-uncertainty, metastasis to the highest mediastinal node station, 5.8%. Compared with R0, R-uncertain resections with mediastinal nodes, no mediastinal nodes, and no nodes had adjusted hazard ratios of 1.28 (95% CI: 1.10-1.48), 1.47 (95% CI: 1.24-1.74), and 1.74 (95% CI: 1.37-2.21), respectively, suggesting a dose-response relationship between nodal R-uncertainty and survival. Accounting for mediastinal nodal involvement, the highest mediastinal station involvement was not independently prognostic. The incomplete resection variables were uniformly prognostic.

CONCLUSIONS

The proposed R classification recategorization variables were mostly prognostic, except the highest mediastinal nodal station involvement. Further categorization of R-uncertainty by severity of nodal quality deficit should be considered.

Effectiveness of Implemented Interventions on Pathologic Nodal Staging of Non-Small Cell Lung Cancer

BACKGROUND

Accurate pathologic nodal staging improves early stage non-small cell lung cancer survival. In an ongoing implementation study, we measured the impact of a surgical lymph node specimen collection kit and a more thorough pathologic gross dissection method on attainment of guideline-recommended pathologic nodal staging quality.

METHODS

We prospectively collected data on curative intent non-small cell lung cancer resections from 2009 to 2016 from 11 hospitals in four contiguous Dartmouth Hospital referral regions. We categorized patients into four groups based on exposure to the two interventions in our staggered implementation study design. We used χ² tests to examine the differences in demographic and disease characteristics and surgical quality criteria across implementation groups.

RESULTS

Of 2,469 patients, 1,615 (65%) received neither intervention; 167 (7%) received only the pathology intervention; 264 (11%) received only the surgery intervention; and 423 (17%) had both. Rates of nonexamination of lymph nodes reduced sequentially in the order of no intervention, novel dissection, kit, and combined interventions, including nonexamination of any lymph nodes and hilar/intrapulmonary and mediastinal nodes (p < 0.001 for all comparisons). The rates of attainment of National Comprehensive Cancer Network, Commission on Cancer, American Joint Committee on Cancer, and American College of Surgeons Oncology Group guidelines increased significantly in the same sequential order (p < 0.001 for all comparisons).

CONCLUSIONS

The combined effect of two interventions to improve pathologic lymph node examination has a greater effect on attainment of a range of surgical quality criteria than either intervention alone.