The impact of a novel lung gross dissection protocol on intrapulmonary lymph node retrieval from lung cancer resection specimens

Standardized intrapulmonary lymph node dissection in lung cancer specimens: A national Colombian analysis

Objective

In patients with non-small cell lung cancer, lymph node assessment is essential for appropriate staging. The intrapulmonary lymph nodes (IPLNs) should be considered when assigning the N stage but are infrequently evaluated in Colombian centers, resulting in understaging that may hinder optimal treatment.

Methods

We conducted a prospective study of IPLN dissection in patients with clinical stage I or II non-small cell lung cancer who underwent surgical resection at 9 institutions in Colombia between 2021 and 2023. IPLN dissection was performed by trained surgeons who collected lymph nodes from fresh specimens after resection and before formalin fixation.

Results

One hundred patients were eligible for the analysis. Their mean age was 67 ± 10.9 years, and 76% were women. Most (74%) had adenocarcinoma, 20% had neuroendocrine tumors, and 6% had squamous cell carcinoma. Successful sampling and histopathologic analysis of at least one IPLN station was obtained in 85% of patients, 9% had upstaging due to positive N2 lymph nodes, and 5% had upstaging due to positive N1 lymph nodes. Among the patients with pN0 or pN1 disease, 3.2% (3 out of 91) were upstaged exclusively due to positive IPLNs.

Conclusions

Fresh-specimen dissection to collect IPLNs is appropriate and feasible to achieve more accurate pathological staging in Colombian lung cancer patients. In clinical N0 patients, IPLN dissection maximizes selection for adjuvant therapy.

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.

Lobe-Specific Lymph Node Dissection May be Feasible for Clinical N0 Solid-Predominant Part-Solid Lung Adenocarcinoma With Solid Component Diameter ≤ 2 cm

BACKGROUND

Lymph node (LN) involvement was not rare in patients with radiological solid-predominant part-solid nodules (PSNs). The lymph node dissection (LND) strategy remained unclear.

MATERIALS AND METHODS

Six hundred seventy-two patients with clinical N0 solid-predominant PSNs (0.5 < consolidation-to-tumor ratio < 1) receiving systematic LND (development cohort, n = 598) or limited LND (validation cohort A, n = 74) at 2 Chinese institutions from 2008 to 2016 were collected. The development cohort was utilized to investigate the incidence and pattern of LN metastasis. Lobe-specific LN metastasis pattern was defined as superior mediastinal LN involvement from upper-lobe tumor or inferior mediastinal LN involvement from lower-lobe tumor. To further validate the LN metastasis pattern observed in the development cohort, validation cohort B consisting of 7273 patients with primary lung adenocarcinomas who received surgery from 2016 to 2021 was identified. The clinical outcomes between the development cohort and validation cohort A were compared in order to assess the feasibility of limited LND.

RESULTS

LN involvement rate for solid-predominant PSNs was 10.0%. Larger solid component diameter (P = .005) was independently associated with increased risk of LN involvement. In upper/lower lobes solid-predominant PSNs with solid component diameter ≤ 2 cm, a lobe-specific LN involvement pattern was identified. Further validation indicated that the observed mediastinal LN involvement pattern was generalizable, and the oncologic outcomes did not vary by the extent of LND in solid-predominant PSNs with solid component diameter ≤ 2 cm.

CONCLUSION

Lobe-specific LND might be feasible for solid-predominant PSNs with solid component diameter ≤ 2 cm. For other solid-predominant PSNs, systematic LND should be recommended.

The impact of pathology grossing protocol measures to improve pathologic nodal staging in lung cancer

OBJECTIVE

Accurate assessment of lymph node (LN) status is essential for proper staging of resected lung cancer specimens. Here, we assessed pathology-centric interventions to increase the number of peribronchial LNs identified and evaluated in anatomic lung cancer resection specimens as part of a quality improvement initiative.

MATERIALS AND METHODS

All non-small cell lung cancer (NSCLC) anatomic resection specimens from 2017 to 2020 were evaluated, comprising two years pre-intervention and one year post-intervention. We instituted 3 measures to increase peribronchial LN yield: 1) educational grossing sessions for pathology assistants and residents, 2) directions to submit additional peribronchial tissue if no LNs were identified grossly, and 3) a hard-stop prior to sign-out by the attending pathologist if no peribronchial LNs were identified.

RESULTS

Of the total 227 resection specimens for NSCLC, 107/151 (70.9%) of specimens prior to the intervention had peribronchial LNs identified, whereas after the intervention significantly more (66/76, 86.8%, p < 0.01) specimens had peribronchial LNs identified. In addition, the mean number of peribronchial LNs identified significantly increased from 2.7 ± 3.3 pre-intervention to 4.3 ± 4.0 post-intervention (p < 0.001). Further analysis revealed a strong correlation between peribronchial LN metastases with both overall tumor size and invasive component size (for adenocarcinomas), correlation coefficient 0.974, p < 0.0001.

CONCLUSION

Establishing focused grossing measures by pathology led to a significant increase in the number of peribronchial LNs identified and assessed during histopathologic evaluation of anatomic lung cancer resection specimens. Larger tumors are more likely to have occult peribronchial LN metastases, which may warrant more aggressive peribronchial LN assessment for larger tumors.

Skip metastasis in mediastinal lymph node is a favorable prognostic factor in N2 lung cancer patients: a meta-analysis

Background

Skip metastasis is a common lymph node metastatic pattern in non-small cell lung cancer (NSCLC). The relationship between skip metastasis and specific clinicopathologic factors and the prognostic value of skip metastasis are controversial.

Methods

A systematic search and analysis of skip metastasis in NSCLC was conducted in the databases of PubMed, EMBASE, and Web of Science up to Dec 2019. Summarized hazard ratio (HR), mean difference (MD), and odds ratio (OR) with associated 95% confidence intervals (CI) were evaluated to investigating the relationship between skip metastasis and overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS) and clinicopathological features in NSCLC.

Results

29 studies with a total of 1,806 skip and 4,670 non-skip N2 patients were included. The upper lobe tumor showed a higher rate of skip metastasis compared with lower lobe one (RR =1.16, 95% CI: 1.00–1.34, P=0.044, I²=39.8%). The presence of skip metastasis correlated with superior overall survival (HR =0.74, 95% CI: 0.66–0.83, P<0.001, I²=48.2%) and DFS or RFS (HR =0.71, 95% CI: 0.61–0.84, P<0.001, I²=18.2%). Further subgroup analyses indicated similar results in articles that reported intrapulmonary lymph node dissection (HR =0.67, 95% CI: 0.57–0.77, P<0.001, I²=0).

Conclusions

The results indicate that the presence of skip metastasis is associated with a marked increase in survival of NSCLC patients compared to patients with non-skip N2 metastasis. These results suggest that skip metastasis might be a distinct subgroup for purposes of N staging of NSCLC patients, and intrapulmonary lymph node assessment is needed.

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.

The IASLC Lung Cancer Staging Project: Analysis of Resection Margin Status and Proposals for Residual Tumor Descriptors for Non-Small Cell Lung Cancer

OBJECTIVE

Our aim was to validate the prognostic relevance in NSCLC of potential residual tumor (R) descriptors, including the proposed International Association for the Study of Lung Cancer definition for uncertain resection, referred to as R(un).

METHODS

A total of 14,712 patients undergoing resection with full R status and survival were analyzed. The following were also evaluated: whether fewer than three N2 stations were explored, lobe-specific nodal dissection, extracapsular extension, highest lymph node station status, carcinoma in situ at the bronchial resection margin, and pleural lavage cytologic examination result. Revised categories of R0, R(un), R1, and R2 were tested for survival impact.

RESULTS

In all, 14,293 cases were R0, 263 were R1, and 156 were R2 (median survivals not reached, 33 months, and 29 months, respectively). R status correlated with T and N categories. A total of 9290 cases (63%) had three or more N2 stations explored and 6641 cases (45%) had lobe-specific nodal dissection, correlated with increasing pN2. Extracapsular extension was present in 62 of 364 cases with available data (17%). The highest station was positive in 942 cases (6.4%). The pleural lavage cytologic examination result was positive in 59 of 1705 cases (3.5%): 13 had carcinoma in situ at the bronchial resection margin. After reassignment because of inadequate nodal staging in 56% of cases, 6070 cases were R0, 8185 were R(un), 301 were R1, and 156 were R2. In node-positive cases, the median survival times were 70, 50, and 30 months for R0, R(un) (p < 0.0001), and R1 (p < 0.001), respectively, with no significant difference between R0 and R(un) in pN0 cases.

CONCLUSIONS

R descriptors have prognostic relevance, with R(un) survival stratifying between R0 and R1. Therefore, a detailed evaluation of R factor is of particular importance in the design and analyses of clinical trials of adjuvant therapies.

Survival Before and After Direct Surgical Quality Feedback in a Population-Based Lung Cancer Cohort

BACKGROUND

Surgical resection is the main curative modality for non-small cell lung cancer (NSCLC), but variation in the quality of care contributes to suboptimal survival rates. Improving surgical outcomes by eliminating quality deficits is a key strategy for improving population-level lung cancer survival. We evaluated the long-term survival effect of providing direct feedback on institutional performance in a population-based cohort.

METHODS

The Mid-South Quality of Surgical Resection cohort includes all NSCLC resections at 11 hospitals in four contiguous Dartmouth Hospital Referral Regions in Arkansas, Mississippi, and Tennessee. We evaluated resections from 2004 to 2013, before and after onset of a benchmarked performance feedback campaign to surgery and pathology teams in 2009.

RESULTS

We evaluated 2,206 patients: 56% preintervention (pre-era) and 44% postintervention (post-era). Preoperative positron emission tomography/computed tomography (46% vs 82%, p < 0.0001), brain scans (6% vs 21%, p < 0.0001), and bronchoscopy (8% vs 27%, p < 0.0001) were more frequently used in the post-era. Patients had 5-year survival of 47% (44% to 50%) in the pre-era compared with 53% (50% to 56%) in the post-era (p = 0.0028). The post-era had an adjusted hazard ratio of 0.85 (95% confidence interval [CI], 0.75 to 0.97; p = 0.0158) compared with the pre-era. This differed by extent of resection (p = 0.0113): compared with the pre-era, the post-era adjusted hazard ratio was 0.49 (95% CI, 0.33 to 0.72) in pneumonectomy, 0.91 (95% CI, 0.79 to 1.05) in lobectomy/bilobectomy, and 0.85 (95% CI, 0.63 to 1.15) in segmentectomy/wedge resections.

CONCLUSIONS

Overall survival after surgical resection improved significantly in a high lung cancer mortality region of the United States. Reasons may include better selection of patients for pneumonectomy and more thorough staging.

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.

Eighth Edition Staging of Thoracic Malignancies: Implications for the Reporting Pathologist

Context The Staging and Prognostic Factors Committee of the International Association for the Study of Lung Cancer, in conjunction with the International Mesothelioma Interest Group, the International Thymic Malignancy Interest Group, and the Worldwide Esophageal Cancer Collaboration, developed proposals for the 8th edition of their respective tumor, node, metastasis (TNM) staging classification systems. Objective To review these changes and discuss issues for the reporting pathologist. Data Sources Proposals were based on international databases of lung (N = 94 708), with an external validation using the US National Cancer Database; mesothelioma (N = 3519); thymic epithelial tumors (10 808); and epithelial cancers of the esophagus and esophagogastric junction (N = 22 654). Conclusions These proposals have been mostly accepted by the Union for International Cancer Control and the American Joint Committee on Cancer and incorporated into their respective staging manuals (2017). The Union for International Cancer Control recommended implementation beginning in January 2017; however, the American Joint Committee on Cancer has deferred deployment of the eighth TNM until January 1, 2018, to ensure appropriate infrastructure for data collection. This manuscript summarizes the updated staging of thoracic malignancies, specifically highlighting changes from the 7th edition that are relevant to pathologic staging. Histopathologists should become familiar with, and start to incorporate, the 8th edition staging in their daily reporting of thoracic cancers henceforth.

Relationship between Contrast-Enhanced CT and Clinicopathological Characteristics and Prognosis of Non-Small Cell Lung Cancer

BACKGROUND

This study investigated the relationship between contrast-enhanced computed tomography (CECT) and clinicopathological characteristics and prognosis of non-small cell lung cancer (NSCLC).

METHODS

A total of 198 NSCLC patients admitted to Enze Hospital from February 2009 to July 2012 underwent pre-surgical CECT to investigate parameters such as tumor size, CECT enhancement, lymph node enlargement, and lymph node size. Chi-square and log-rank tests were used to analyze associations between CECT parameters and pathological features as well as correlations of CECT parameters with prognosis. A Cox proportional hazard model and logistic regression analysis were applied to identify independent risk factors for prognosis.

RESULTS

Tumor size, CECT enhancement, and lymph node enlargement and size were related to degree of differentiation, TNM stage, and lymph node metastasis. Tumor size, lymph node enlargement and metastasis, lymph node size, and CECT enhancement were independent risk factors for NSCLC prognosis. Large tumors and lymph nodes, tumor enhancement, and enlarged and metastatic lymph nodes indicated a poor prognosis.

CONCLUSION

Our study indicates that CECT features can be associated with clinicopathological characteristics and can predict the prognosis of patients with NSCLC.

Quality Initiatives: Baby Steps in the Right Direction

Quality improvement requires novel, and perhaps simple, ideas for adaptation, like a lymph node kit, and the ability to objectively document benchmark upgrading.

Evolution in the Surgical Care of Patients With Non-Small Cell Lung Cancer in the Mid-South Quality of Surgical Resection Cohort

Surgery is the most important curative treatment modality for patients with early-stage non-small cell lung cancer (NSCLC). We examined the pattern of surgical resection for NSCLC in a high incidence and mortality region of the United States over a 10-year period (2004-2013) in the context of a regional surgical quality improvement initiative. We abstracted patient-level data on all resections at 11 hospitals in 4 contiguous Dartmouth Hospital Referral Regions in North Mississippi, East Arkansas, and West Tennessee. Surgical quality measures focused on intraoperative practice, with emphasis on pathologic nodal staging. We used descriptive statistics and trend analyses to assess changes in practice over time. To measure the effect of an ongoing regional quality improvement intervention with a lymph node specimen collection kit, we used period effect analysis to compare trends between the preintervention and postintervention periods. Of 2566 patients, 18% had no preoperative biopsy, only 15% had a preoperative invasive staging test, and 11% underwent mediastinoscopy. The rate of resections with no mediastinal lymph nodes examined decreased from 48%-32% (P < 0.0001), whereas the rate of resections examining 3 or more mediastinal stations increased from 5%-49% (P < 0.0001). There was a significant period effect in the increase in the number of N1, mediastinal, and total lymph nodes examined (all P < 0.0001). A quality improvement intervention including a lymph node specimen collection kit shows early signs of having a significant positive effect on pathologic nodal examination in this population-based cohort. However, gaps in surgical quality remain.

Missed Intrapulmonary Lymph Node Metastasis and Survival After Resection of Non-Small Cell Lung Cancer

BACKGROUND

Pathologic nodal stage is a key prognostic factor for patients with surgically resected lung cancer. We previously described the extent of missed intrapulmonary nodal metastasis in a cohort of patients treated at institutions in metropolitan Memphis, TN. With long-term follow-up, we now quantify the survival impact of missed nodal metastasis.

METHODS

We conducted a prospective cohort study to evaluate inadvertently discarded lymph nodes in re-dissected remnant lung resection specimens from lung cancer patients. Retrieved material was histologically examined and classified as lymph nodes with and without metastasis. Survival information was obtained from hospital cancer registries. We plotted survival distributions with the use of the Kaplan-Meier method and evaluated them with proportional hazards models that controlled for important demographic and clinical factors.

RESULTS

The study included 110 patients who were 54% women and 69% white. Discarded lymph nodes with metastasis were found in 25 patients (23%). Patients with missed lymph node metastasis had an increased risk of death with an unadjusted hazard ratio of 2.0 (p = 0.06) and an adjusted hazard ratio of 1.4 (p = 0.45) compared with patients without missed lymph node metastasis. Patients with more than 2 missed lymph nodes with metastasis had 4.8 times the hazard of death (p = 0.0005) compared with patients without missed lymph node metastasis (adjusted hazard ratio 6.5, p = 0.0001).

CONCLUSIONS

Metastasis to inadvertently discarded intrapulmonary lymph nodes from lung cancer resection specimens was associated with reduced survival. A more rigorous gross dissection protocol for lung cancer resection specimens may provide prognostically useful information.

Survival Implications of Variation in the Thoroughness of Pathologic Lymph Node Examination in American College of Surgeons Oncology Group Z0030 (Alliance)

BACKGROUND

Accurate pathologic nodal staging mandates effective collaboration between surgeons and pathologists. The American College of Surgeons Oncology Group Z0030 trial (ACOSOG Z0030) tightly controlled surgical lymphadenectomy practice but not pathologic examination practice. We tested the survival impact of the thoroughness of pathologic examination (using the number of examined lymph nodes as a surrogate).

METHODS

We re-analyzed the mediastinal lymph node dissection arm of ACOSOG Z0030, using logistic regression and Cox proportional hazards models.

RESULTS

Of 513 patients, 435 were pN0, 60 were pN1, and 17 were pN2. The mean number of mediastinal lymph nodes examined was 13.5, 13.1, and 17.1; station 10 lymph nodes were 2.4, 2.7, and 2.6; station 11 to 14 nodes were 4.6, 6.1, and 6.7; and total lymph nodes were 19.7, 21.3, and 25.4 respectively. The pN category and histologic evaluation were associated with increased number of examined intrapulmonary lymph nodes. Patients with pN1 had more non-hilar N1 nodes than patients with pN0, patients with N2 had more N2 nodes examined than patients with pN0 or pN1. Patients with pN0 had better survival with examination of more N1 nodes; patients with pN1 had better survival with increased mediastinal nodal examination; the likelihood of discovering N2 disease was significantly associated with increased examination of mediastinal and non-hilar N1 lymph nodes.

CONCLUSIONS

Despite rigorously standardized surgical hilar/mediastinal lymphadenectomy, the number of lymph nodes examined was associated with the likelihood of detecting nodal metastasis and survival. This may indicate an effect of incomplete pathologic examination.

Improving the pathologic evaluation of lung cancer resection specimens

Accurate post-operative prognostication and management heavily depend on pathologic nodal stage. Patients with nodal metastasis benefit from post-operative adjuvant chemotherapy, those with mediastinal nodal involvement may also benefit from adjuvant radiation therapy. However, the quality of pathologic nodal staging varies significantly, with major survival implications in large populations of patients. We describe the quality gap in pathologic nodal staging, and provide evidence of its potential reversibility by targeted corrective interventions. One intervention, designed to improve the surgical lymphadenectomy, specimen labeling, and secure transfer between the operating theatre and the pathology laboratory, involves use of pre-labeled specimen collection kits. Another intervention involves application of an improved method of gross dissection of lung resection specimens, to reduce the inadvertent loss of intrapulmonary lymph nodes to histologic examination for metastasis. These corrective interventions are the subject of a regional dissemination and implementation project in diverse healthcare systems in a tri-state region of the United States with some of the highest lung cancer incidence and mortality rates. We discuss the potential of these interventions to significantly improve the accuracy of pathologic nodal staging, risk stratification, and the quality of specimens available for development of stage-independent prognostic markers in lung cancer.