Clinical implications of the margin cytology findings and margin/tumor size ratio in patients who underwent pulmonary excision for peripheral non-small cell lung cancer

Impacts of Positive Margins and Surgical Extent on Outcomes After Early-Stage Lung Cancer Resection

BACKGROUND

Sublobar resection of early-stage non-small cell lung cancer (NSCLC) is increasingly considered appropriate but may compromise margins compared with lobectomy. This study evaluated resection extent, margin status, and survival in patients with clinical stage I NSCLC.

METHODS

Patients with clinical T1-2 N0 M0 NSCLC in the National Cancer Database (2006-2020) who were treated with primary surgery were compared stratified by margin status. The potential benefit of radiation was explored in subgroup analysis of patients who underwent sublobar resection with positive margins.

RESULTS

Positive margins occurred in 5089 (2.8%) of 181,824 patients and were more common in sublobar resections compared with lobectomy (4.3% vs 2.4%; P < .001). Sublobar resection had the strongest association with positive margins in multivariable analysis (odds ratio, 2.06; 95% CI, 1.91-2.23; P < .001). Patients with positive margins were more likely to undergo both adjuvant chemotherapy (16% vs 13%; P < .001) and radiation (17% vs 1%; P < .001) but had worse survival in univariate analysis (44.0% 5-year overall survival vs 69.2%; P < .001) and multivariable Cox analysis (hazard ratio, 1.71; 95% CI, 1.63-1.78; P < .001) in the entire cohort, as well as in a univariate subset analysis of lobectomy (46.9% vs 70.4%; P < .001) and sublobar resection (37.5% vs 64.1%; P < .001). Postoperative radiation for patients who underwent sublobar resection with positive margins did not improve 5-year overall survival (36.3% for irradiated patients vs 38.3% for nonirradiated patients; P = .57), and patients who underwent sublobar resection with positive margins who were treated with radiation had survival inferior to that of patients who underwent lobectomy with negative margins.

CONCLUSIONS

Positive margins occur more frequently after sublobar resection of clinical stage I NSCLC compared with lobectomy. Patients with positive margins have worse survival than patients who undergo complete resection and are not rescued by postoperative radiation.

What Is an Adequate Margin During Sublobar Resection of ≤3 cm N0 Subsolid Lung Adenocarcinomas?

BACKGROUND

Sublobar resection offers noninferior survival vs lobectomy for ≤2 cm non-small cell lung cancer and is commonly used for subsolid tumors. Although data exist for solid tumors, the minimum adequate margin of resection for subsolid adenocarcinomas remains unclear.

METHODS

This was a retrospective review of 1101 adenocarcinoma resections at our institution from 2006 to 2022. Inclusion criteria were tumors ≤3 cm with ≥10% radiographic ground glass, excised by sublobar resection. Exclusions were positive nodes or positive or unreported margin. The primary outcome was the rate of local recurrence (LR) at multiple thresholds of margin distance. The relationship between margin distance and solid component size was also explored.

RESULTS

Inclusion criteria were met by 194 patients. Median (interquartile range) tumor diameter and margin distance were 12 mm (9-17 mm) and 10 mm (5-17 mm), respectively. Median follow-up was 42.5 months. There was a progressive increase in LR with diminishing margin (0.1-cm decrements) from 1.5 cm to 0.5 cm. The difference in the rate of LR between "over" (n = 143) and "under" (n = 51) was most significant at 0.5 cm (8 of 51 [15.7%] vs 6 of 143 [4.2%]; P = .01) but did not reach α adjusted for multiple comparisons. On Cox regression for LR-free survival, margin ≤0.5 cm (P = .19) and solid component percentage (P = .14) trended to significance. Combining these using a ratio of margin distance-to-solid component size, a ratio of ≤1 showed a significantly higher rate of LR (7 [14.3%] vs 2 [2.0%], P = .009). Treatment of LRs provided at least intermediate-term survival in 87% of recurrences (median postrecurrence follow-up was 44 months).

CONCLUSIONS

During sublobar resection of subsolid lung adenocarcinomas, a margin distance-to-solid component size ratio of >1.0 appears to be a more reliable factor than margin distance alone to minimize local recurrence. Local recurrence, however, may not impact survival in patients with subsolid adenocarcinomas if timely treatment is administered.

Quantification of Resection Margin following Sublobar Resection in Lung Cancer Patients through Pre- and Post-Operative CT Image Comparison: Utilizing a CT-Based 3D Reconstruction Algorithm

Sublobar resection has emerged as a standard treatment option for early-stage peripheral non-small cell lung cancer. Achieving an adequate resection margin is crucial to prevent local tumor recurrence. However, gross measurement of the resection margin may lack accuracy due to the elasticity of lung tissue and interobserver variability. Therefore, this study aimed to develop an objective measurement method, the CT-based 3D reconstruction algorithm, to quantify the resection margin following sublobar resection in lung cancer patients through pre- and post-operative CT image comparison. An automated subvascular matching technique was first developed to ensure accuracy and reproducibility in the matching process. Following the extraction of matched feature points, another key technique involves calculating the displacement field within the image. This is particularly important for mapping discontinuous deformation fields around the surgical resection area. A transformation based on thin-plate spline is used for medical image registration. Upon completing the final step of image registration, the distance at the resection margin was measured. After developing the CT-based 3D reconstruction algorithm, we included 12 cases for resection margin distance measurement, comprising 4 right middle lobectomies, 6 segmentectomies, and 2 wedge resections. The outcomes obtained with our method revealed that the target registration error for all cases was less than 2.5 mm. Our method demonstrated the feasibility of measuring the resection margin following sublobar resection in lung cancer patients through pre- and post-operative CT image comparison. Further validation with a multicenter, large cohort, and analysis of clinical outcome correlation is necessary in future studies.

Pulmonary Surgical Margins for Metastatic Osteosarcoma: Is Negative Margin Enough?

BACKGROUND

In advanced osteosarcoma, the lung is the most frequent site of distant metastasis, with metastasectomy often used for local disease control. The influence of pulmonary resection margin length on outcomes for osteosarcoma has not been well explored. This study sought to evaluate the impact of margin length relative to tumor size on local recurrence and survival in lung-limited metastatic osteosarcoma.

METHODS

Patients with metastatic osteosarcoma who underwent lung resection between 2000 and 2020 were identified from a single institution. Clinicopathologic variables were collected. The margin length-to-tumor size ratio (MTR) was calculated per nodule and classified relative to an MTR of 0.5. The primary outcome was development of local recurrence per nodule. Multivariate logistic regression was used to investigate covariates.

RESULTS

A total of 142 patients with 689 nodules met inclusion criteria, with mean age of 35.6 years (interquartile range [IQR], 20.9-46.6 years). Patients were predominantly male (n = 87; 61.3%) and White (n = 106; 72.5%). Most nodules (n = 644; 93.5%) were resected through thoracotomy. The mean tumor size was 0.8 cm (IQR, 0.5-1.70 cm), with an average margin length of 0.3 cm (IQR, 0.1-0.7 cm). Among all nodules, 299 (43.4%) had an MTR >0.5. Systemic therapy was received by 94 patients (66.2%) preoperatively and by 100 patients (70.4%) postoperatively. Importantly, the study found that an MTR >0.5 conferred a protective effect against disease recurrence (hazard ratio, 0.67; 95% CI, 0.52-0.87; P = .003).

CONCLUSIONS

In resected pulmonary metastatic osteosarcoma, a margin length greater than one-half the size of the pulmonary nodule is associated with a lower incidence of local disease recurrence. This finding has implications for the subsequent need for additional therapy and disease-free status, thus meriting attentive intraoperative consideration.

Recurrence/prognosis estimation using a molecularly positive surgical margin-based model calls for alternative curative strategies in pIIIA/N2 NSCLC

Stage pIIIA/N2 non-small cell lung cancer (NSCLC) is primarily treated by complete surgical resection combined with neoadjuvant/adjuvant therapies. However, up to 40% of patients experience tumor recurrence. Here, we studied 119 stage pIIIA/N2 NSCLC patients who received complete surgery plus adjuvant chemotherapy (CT) or chemoradiotherapy (CRT). The paired tumor and resection margin samples were analyzed using next-generation sequencing (NGS). Although all patients were classified as negative resection margins by histologic methods, NGS revealed that 47.1% of them had molecularly positive surgical margins. Patients who tested positive for NGS-detected residual tumors had significantly shorter disease-free survival (DFS) (P = 0.002). Additionally, metastatic lymph node ratio, erb-b2 receptor tyrosine kinase 2 (ERBB2) mutations, and SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 4 (SMARCA4) mutations were also independently associated with DFS. We used these four features to construct a COX model that could effectively estimate recurrence risk and prognosis. Notably, mutational profiling through broad-panel NGS could more sensitively detect residual tumors than the conventional histologic methods. Adjuvant CT and adjuvant CRT exhibited no significant difference in eliminating locoregional recurrence risk for stage pIIIA/N2 NSCLC patients with molecularly positive surgical margins.

Application value of CT-guided localization using a coil in combination with medical adhesive in sublobar resection

PURPOSE

To explore the application value of CT-guided localization using a coil in combination with medical adhesive in sublobar resection.

METHODS

The clinical data of 90 patients who had small pulmonary nodules and received thoracoscopic sublobar resection during the period from September 2021 to October 2022 in the Department of Thoracic Surgery, Juxian People's Hospital, Shandong Province, were retrospectively analyzed.

RESULTS

The diameters of 95 pulmonary nodules in the 90 patients in the whole group ranged from 0.40 to 1.24 cm, and their distances from the visceral pleura ranged from 0.51 to 2.15 cm. In these patients, percutaneous lung puncture was successfully performed under local anesthesia, through which coils were implanted in the nodules and medical adhesive was injected around the nodules, with a success rate of localization of 100%. Localization complications included 10 cases of asymptomatic pneumothorax, 9 cases of intrapulmonary hemorrhage, 5 cases of severe pain, and 1 case of pleural reaction, all of which required no special treatment. After preoperative localization, the success rate of resection of pulmonary nodules was 100%, and sufficient surgical margins were obtained.

CONCLUSION

CT-guided localization using a coil in combination with medical adhesive is a safe, effective, and simple localization method that can meet the requirements of thoracic surgeons for intraoperative localization; for small pulmonary nodules, especially those small-sized and deep-located ground-glass nodules containing few solid mass, this method has important clinical application value, which is a preoperative localization technique worthy of wide application in clinical practice.

A guide for managing patients with stage I NSCLC: deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 2: systematic review of evidence regarding resection extent in generally healthy patients

Background

Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options (lobectomy, segmentectomy, wedge, stereotactic body radiotherapy, thermal ablation), weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.

Methods

A PubMed systematic review from 2000-2021 of outcomes after lobectomy, segmentectomy and wedge resection in generally healthy patients is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons with at least some adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.

Results

In healthy patients there is no short-term benefit to sublobar resection vs. lobectomy in randomized and non-randomized comparisons. A detriment in long-term outcomes is demonstrated by adjusted non-randomized comparisons, more marked for wedge than segmentectomy. Quality-of-life data is confounded by the use of video-assisted approaches; evidence suggests the approach has more impact than the resection extent. Differences in pulmonary function tests by resection extent are not clinically meaningful in healthy patients, especially for multi-segmentectomy vs. lobectomy. The margin distance is associated with the risk of recurrence.

Conclusions

A systematic, comprehensive summary of evidence regarding resection extent in healthy patients with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation on which to build a framework for individualized clinical decision-making.

Is lobectomy superior to sub-lobectomy in non-small cell lung cancer with pleural invasion? A population-based competing risk analysis

Background

Pleural invasion (PL) has been regarded as an unfavorable prognostic factor for non-small cell lung cancer (NSCLC). But there was no agreement on the optimal surgical extent in NSCLC patients with PL. We aimed to compare the survival outcomes of lobectomy and sub-lobectomy in these patients.

Method

2717 patients were included in the Surveillance, Epidemiology, and End Results (SEER) database and divided into the lobectomy and sub-lobectomy groups. The propensity score matching (PSM) and competing risk analysis were implemented. Then the predictive nomogram was constructed and validated.

Results

2230 Patients received lobectomy while the other 487 patients underwent sub-lobectomy. After 1:1 PSM, the cumulative incidence of cancer-specific death (CSD) was lower in the lobectomy group compared with the sub-lobectomy group (1-year: 12% vs. 15%; 3-year: 30% vs. 37%, 5-year: 34% vs. 45%, P = 0.04). According to the subgroup analysis, the patients who underwent lobectomy suffered lower CSD in the N0–1 stage, adenocarcinoma, and PL-2 cohort (p < 0.05). And there was a significant relationship between the sub-lobectomy group and CSD in the multivariate competing risks regression analysis (HR, 1.26; 95%CI, 1.02–1.56; P = 0.034). Furthermore, a competing event nomogram was constructed to assess the 1-, 3-, and 5-year chances of CSD based on the variables from the multivariate analysis. The 1-, 3-, 5-year area under the receiver operating characteristic curve (AUC) values were 0.720, 0.706, and 0.708 in the training cohort, and 0.738, 0.696, 0.680 in the validation cohorts, respectively. And calibration curves demonstrated ideal consistency between the predicted and observed probabilities of CSD.

Conclusion

Lobectomy should be considered the preferred surgery compared to sub-lobectomy for NSCLC patients with PL. The proposed nomograms presented great prediction ability for these patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09634-w.

Intraoperative computed tomography of a resected lung inflated with air to verify safety surgical margin

Background

During sublobar resection for small, indistinct lung cancer, surgeons may be uncertain as to whether or not the target lesion has been resected and the surgical margin is sufficient. We herein report our procedure for confirming the success of sublobar resection without incising the resected specimen.

Methods

We reviewed our initial experience of 12 patients with intrapulmonary lesions (consolidation diameter ≤1 cm) who underwent thoracoscopic pulmonary wedge resection using autostapler. Six patients had primary adenocarcinoma showing part solid lesion, and remaining six patients had metastatic carcinoma showing purely solid lesion. Intraoperatively, the resected specimen was inflated with air and subjected to computed tomography (CT). The maximum tumor diameter and surgical margin length were measured intraoperatively on CT and postoperatively on formalin-fixed specimen. Surgical stump cytology was also done to verify surgical margin.

Results

According to the intraoperative CT, complete resection was confirmed in all patients. The intraoperative CT-based maximum tumor diameter closely correlated with the macroscopically measured one (r=0.971, P<0.0001). However, the tumor shrunk after formalin-fixation by 16.0% in patients with primary lung cancer (P<0.01), but not in patients with metastatic lung cancer. The intraoperative CT-based margin length closely correlated with the macroscopically measured one (r=0.984, P<0.0001). However, the margin shrunk after formalin-fixation in both patients with primary lung cancer and metastatic lung cancer, by 15.1% and 15.7%, respectively. Stump cytology was negative in all patients. Consequently, no recurrence was found during postoperative follow-up of 23 months (range, 14-31 months).

Conclusions

Intraoperative CT is reliable for diagnosing the presence of a target lesion within the resected specimen as well as for estimating the surgical margin length in patients undergoing sublobar resection for intrapulmonary indistinct lesions.

Feasibility study of a novel wireless localization technique using radiofrequency identification markers for small and deeply located lung lesions

Objectives

Methods

Results

Conclusions

Does surgical margin affect recurrence and survival after sublobar pulmonary resection for lung cancer?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was: How does surgical margin distance affect recurrence and survival after sublobar pulmonary resection for lung cancer? Altogether, 172 papers were found using the search strategy, of which 12 studies with 1946 stage I non-small-cell lung cancer (NSCLC) patients using sublobar resection (wedge resection or segmentectomy) represented to be the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. Overall, 11 cohort studies and 1 prospective study were included. Four cohort studies demonstrated positive prognostic significance of surgical margin with specific cut-off points in each paper (ranged from 9 to 15 mm). Two retrospective studies and 1 prospective study found that a margin-to-tumour ratio of ≥1 was associated with better cytology and prognosis results. Other 5 studies showed that larger margin distance provided a favourable prognosis for NSCLC patients with poor-prognostic factors, including solid-dominant type, high invasive component size and Spread through Air Spaces-positive subtype. After reviewing all the included articles, we conclude that the standard of margin distance of >10 mm or margin-to-tumour ratio  ≥ 1 should be recommended for stage I NSCLC patients undergoing sublobar resection, especially in wedge resection. Patients with poor-prognostic factors like solid-predominant tumour or non-lepidic adenocarcinoma may benefit from larger margin distance and the proper margin distance for them still needs to be determined. For Spread through Air Spaces-positive patients, sublobar resection may not be the alternative to lobectomy.

Surgical Extent for Ground Glass Nodules

As diagnoses of small ground glass nodule (GGN)-type lung adenocarcinoma are increasing due to the increasing frequency of computed tomography (CT) screening, surgical treatment for GGN-type lung adenocarcinoma has rapidly become more common. However, the appropriate surgical extent for these lesions remains unclear; therefore, several retrospective studies have been published and prospectively randomized controlled trials are being undertaken. This article takes a closer look at each clinical study. Convincing evidence must be published on 2 issues for sublobar resection to be accepted as a standard surgical option for GGN lung adenocarcinoma. In the absence of such evidence, it is better to perform lobar resection as long as the patient has sufficient lung function. The first issue is the definition of a sufficient resection margin, and the second is whether lymph node metastasis is conclusively ruled out before surgery. An additional issue is the need for an accurate calculation of the total size and solid size on CT. Given the results of clinical studies so far, wedge resection or segmentectomy shows a good prognosis for GGNs with a total size of 2 cm or less. Therefore, sublobar resection will play a key role even in patients who can tolerate lobectomy.

Multi-disciplinary approach for the management of non-metastatic non-small cell lung cancer in the Middle East and Africa: Expert panel recommendations

The Middle East and Africa (MEA) region, a large geographical area, lies at the confluence of Asian, Caucasian and African races and comprises of a population with several distinct ethnicities. The course of management of non-small cell lung cancer (NSCLC) differs as per patients' performance status as well as stage of disease, requiring personalized therapy decisions. Although management of NSCLC has received a significant impetus in the form of molecularly targeted therapies and immune therapies in last few years, surgery remains gold standard for patients with early-stage disease. In case of unresectable disease, radiotherapy and chemotherapy are the primary management modalities. With newer therapies being approved for treatment of early stage disease, use of multi-disciplinary team (MDT) for comprehensive management of NSCLC is of prime importance. A group of experts with interest in thoracic oncology, deliberated and arrived at a consensus statement for the community oncologists treating patients with NSCLC in the MEA region. The deliberation was based on the review of the published evidence including literature and global and local guidelines, subject expertise of the participating panellists and experience in real-life management of patients with NSCLC. We present the proposed regional adaptations of international guidelines and recommends the MDT approach for management of NSCLC in MEA.

Differential outcomes of residual disease in surgically-resected non-small cell lung cancer and the importance of guideline-concordant adjuvant therapy

Background

Positive mediastinal lymph nodes, a marker for systemic disease, and positive margins, a marker for local disease, following resection of non-small cell lung cancer (NSCLC) are forms of residual disease. The objective of this study is to compare survival of patients with residual disease and to study the effect of receipt of guideline vs. non-guideline concordant care.

Methods

The National Cancer Database (NCDB) was used to identify patients who underwent treatment naïve surgical resection with clinical stage T1-3N0-1M0 NSCLC between 2006–2016 and had pN2 disease, positive surgical margins, or both. Concordant care was determined based on form of chemotherapy and radiation, dosage, volume, modality, and duration. Kaplan-Meier survival curves and log-rank tests were used to compare five-year survival. Multivariable analysis using Cox proportional hazards modeling identified factors that contributed to worse overall survival.

Results

There were 8,189 patients included: pN2 (5,416), positive margins (2,386), and both (387). Five-year survival rates for all patients were pN2 (35.8%), positive margins (33.9%), and both (22.9%) (P<0.0001). On multivariable analysis, positive margins were an independent predictor of better survival relative to pN2 disease (HR =0.729, CI: 0.676, 0.787, P<0.0001). Receipt of non-guideline concordant treatment was an independent predictor of worse survival compared to receipt of guideline-concordant treatment (HR =1.61, CI: 1.504, 1.725, P<0.0001).

Conclusions

In upfront surgical patients, guideline-concordant treatment in the setting of residual disease is associated with better overall survival compared with non-guideline concordant treatment. Pathologic N2 disease is associated with a lower survival rate than positive resection margins, possibly reflecting the systemic nature of pN2 disease.

Long-Term Prognosis of Patients With Resected Adenocarcinoma In Situ and Minimally Invasive Adenocarcinoma of the Lung

INTRODUCTION

The WHO classification of lung tumors defines adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) as cancers with no or limited histologic invasive components. The probability of patients with AIS or MIA being recurrence free for 5 years postoperatively has been found to be 100%. This study aimed to analyze the prognosis of patients with AIS or MIA after more than 5 postoperative years.

METHODS

We reviewed the pathologic findings of 4768 patients who underwent resection for lung cancer between 1998 and 2010. Of these, 524 patients with curative resection for AIS (207 cases, 39.5%) and MIA (317 cases, 60.5%) were included. Postoperative recurrence, survival, and development of secondary primary lung cancer (SPLC) were analyzed.

RESULTS

Of the included patients, 342 (65.3%) were of female sex, 333 (63.5%) were nonsmokers, and 229 (43.7%) underwent sublobar resection. Average pathologic total tumor diameter was 15.2 plus or minus 5.5 mm. Median postoperative follow-up period was 100 months (range: 1-237). No recurrence of lung cancer was observed for either AIS or MIA cases. Estimated 10-year postoperative disease-specific survival rates were 100% and 100% (p = 0.72), and overall survival rates were 95.3% and 97.8% (p = 0.94) for AIS and MIA cases, respectively. Estimated incidence rates of metachronous SPLC at 10 years after surgery were 5.6% and 7.7% for AIS and MIA, respectively (p = 0.45), and these were not correlated with the EGFR mutation status.

CONCLUSIONS

Although the development of metachronous SPLC should be noted, the risk of recurrence is quite low at more than 5 years after resection of AIS and MIA. This finding strengthens the clinical value of distinguishing AIS and MIA from other adenocarcinomas of the lung.

The surgical management of early-stage lung adenocarcinoma: is wedge resection effective?

Background

The aim of the study was to explore the outcomes of wedge resection on patients with early-stage lung adenocarcinoma (LUAD) and further identify potential prognostic factors for these patients.

Methods

A retrospective cohort of 190 patients (99 solitary LUAD and 91 multifocal LUAD) undergone wedge resection from October 2014 to September 2015 was established. Cox proportional-hazards model was used to evaluate the significant clinical prognostic factors. Further, data on patients with multifocal adenocarcinoma after segmentectomy were retrieved and propensity score matching was used to compare the outcomes of patients with multiple pulmonary nodules (MPNs) after wedge resection and segmentectomy.

Results

The 5-year overall survival (OS), progression-free survival (PFS), and lung cancer specific survival of the 190 patients after wedge resection were 95.5%, 87.9%, and 97.7%, respectively. Multivariable analysis showed that MPN [hazard ratio (HR) 3.07; 95% confidence interval (CI), 1.05–8.98] and solid-dominant lesions (HR 15.87; 95% CI, 2.38–105.84) were independently associated with worse PFS. Further, propensity score matching analysis showed that MPN patients had better PFS after segmentectomy compared with wedge resection (94% vs. 80.9%, P=0.008). MPN patients were more likely to perform systematic mediastinal nodal sampling (95.6% vs. 59.3%, P<0.001) after segmentectomy compared to patients who underwent wedge resection.

Conclusions

Wedge resection is a practical option for appropriately selected early-stage LUAD where tumor size is less than 2 cm and has a consolidation-to-tumor ratio ≤0.5. However, for MPNs, wedge resection may be not reliable and alternative procedures such as segmentectomy should be used.

Delivery of eupenifeldin via polymer-coated surgical buttresses prevents local lung cancer recurrence

Lung cancer is the leading cause of cancer deaths worldwide. Unfortunately, high recurrence rates and poor survival remain despite surgical resection and conventional chemotherapy. Local drug delivery systems are a promising intervention for lung cancer treatment with the potential for improved efficacy with reduced systemic toxicity. Here, we describe the development of a chemotherapy-loaded polymer buttress, to be implanted along the surgical margin at the time of tumor resection, for achieving local and prolonged release of a new anticancer agent, eupenifeldin. We prepared five different formulations of buttresses with varying amounts of eupenifeldin, and additional external empty polymer coating layers (or thicknesses) to modulate drug release. The in vitro eupenifeldin release profile depends on the number of external coating layers with the formulation of the greatest thickness demonstrating a prolonged release approaching 90 days. Similarly, the long-term cytotoxicity of eupenifeldin-loaded buttress formulations against murine Lewis lung carcinoma (LLC) and human lung carcinoma (A549) cell lines mirrors the eupenifeldin release profiles and shows a prolonged cytotoxic effect. Eupenifeldin-loaded buttresses significantly decrease local tumor recurrence in vivo and increase disease-free survival in a lung cancer resection model.

Molecular Analysis of Oncogenic Mutations in Resected Margins by Next-Generation Sequencing Predicts Relapse in Non-Small Cell Lung Cancer Patients

Objective

To investigate the genetic mutations in both tumor and marginal tissues in patients with non-small cell lung cancer (NSCLC), and to evaluate the potential prognostic value in patients with margins gene positive.

Methods

Next-generation sequencing (NGS) technique was used to detect genetic mutation in tumor and marginal tissues of the bronchus in 88 patients with NSCLC. Correlation of genetic mutations with pathology, lymph node metastasis, disease-free survival and overall survival was analyzed.

Results

Of the 88 patients, 83 cases (94.3%) had gene mutations in the tumor samples and 12 cases (13.6%) had genetic alterations in their margins. Most of the gene mutations detected were cancer drivers. Six common driver genes between tumor and marginal tissues were identified, including EGFR, TP53, CDKN2A, CTNNB1, BRAF, and NF1. Kaplan–Meier analysis revealed that the median disease-free survival (DFS) was significantly shorter in patients with detectable gene mutations in marginal tissues compared with patients without mutations in margins (30.7 versus 24.4 months, log-rank χ² = 4.78, P =0.029). Consistently, a shorter median OS was observed in patients harboring gene mutations in margins compared with patients with no mutations in margins (49.1 versus 32.2 months, log-rank χ² = 3.669, P =0.055).

Conclusion

These findings identify the presence of oncogenic alterations in microscopically negative margins in NSCLC patients associated with elevated risk of relapse and shorter survival time. Thus, examination of microscopically negative margins by NGS represents a valuable approach to predict the clinical outcome of NSCLC patients.

Oncologic Outcomes of Surgery Versus SBRT for Non-Small-Cell Lung Carcinoma: A Systematic Review and Meta-analysis

BACKGROUND

The optimal treatment of stage I non-small-cell lung carcinoma is subject to debate. The aim of this study was to compare overall survival and oncologic outcomes of lobar resection (LR), sublobar resection (SR), and stereotactic body radiotherapy (SBRT).

METHODS

A systematic review and meta-analysis of oncologic outcomes of propensity matched comparative and noncomparative cohort studies was performed. Outcomes of interest were overall survival and disease-free survival. The inverse variance method and the random-effects method for meta-analysis were utilized to assess the pooled estimates.

RESULTS

A total of 100 studies with patients treated for clinical stage I non-small-cell lung carcinoma were included. Long-term overall and disease-free survival after LR was superior over SBRT in all comparisons, and for most comparisons, SR was superior to SBRT. Noncomparative studies showed superior long-term overall and disease-free survival for both LR and SR over SBRT. Although the papers were heterogeneous and of low quality, results remained essentially the same throughout a large number of stratifications and sensitivity analyses.

CONCLUSION

Results of this systematic review and meta-analysis showed that LR has superior outcomes compared to SBRT for cI non-small-cell lung carcinoma. New trials are underway evaluating long-term results of SBRT in potentially operable patients.

Sublobectomy versus lobectomy for long-term survival outcomes of early-stage non-small cell lung cancer with a tumor size ≤2 cm accompanied by visceral pleural invasion: a SEER population-based study

Background

The optimal surgical strategy for early-stage non-small cell lung cancer (NSCLC) with visceral pleural invasion (VPI) remains unclear. Due to limited prospective comparative data for these surgical modalities, the objective of the current study was to compare the long-term survival outcomes of sublobectomy (Sub) versus lobectomy (Lob) for NSCLC with a tumor size ≤2 cm and VPI.

Methods

Patients with early-stage NSCLC characterized by VPI diagnosed between 2004 and 2013 were identified from the Surveillance, Epidemiology, and End Results (SEER) program. The baseline demographic and cancer characteristics, treatment information as well as survival outcome data were extracted from the SEER database, and confounders were balanced by propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) analyses. Lung disease-specific survival (DSS) and overall survival (OS) rates were compared with Cox proportional hazards (PH) regression models based on the unmatched cohort, the propensity-based matched cohort, and the IPTW cohort.

Results

Of the 1,386 patients enrolled, 1,000 (72.15%) and 386 (27.85%) underwent lobectomy and sublobectomy, respectively. The 5-year DSS rate was 78.64% for the lobectomy group and 59.47% for the sublobectomy group. Cox regression models demonstrated that the operation type (Sub vs. Lob) was an independent prognostic factor for early-stage NSCLC with VPI based on the three different cohorts. Patients who underwent lobectomy showed better long-term DSS and OS rates than those treated with sublobectomy after PSM [DSS: hazard ratio (HR) 0.689, 95% confidence interval (CI): 0.490–0.968, P=0.032; OS: HR 0.723, 95% CI: 0.549–0.953, P=0.021]. The IPTW analysis yielded similar results.

Conclusions

Lobectomy showed superior long-term survival compared with sublobectomy in patients with early-stage NSCLC with a tumor size ≤2 cm and VPI.

Carinal resection

Tracheobronchial tumors with involvement of the carina represent a challenging problem in the pulmonary surgery. Carinal resection is referred to removal and reconstruction of the airway itself, whereas concomitant removal of the lung parenchyma (usually a whole lung) is termed as carinal pneumonectomy. Thorough preoperative workup of these patients is mandatory. Meticulous surgical technique and aggressive postoperative management is required for the best outcomes in these difficult cases. In the paper authors review surgical technique, evaluation and management of this challenging patient population.

Optimal sublobar resection for c-stage I non-small cell lung cancer: significance of margin distance to tumor size ratio and margin cytology (Supplementary analysis of KLSG-0801): complete republication

BACKGROUND

Sublobar resection for lung cancer is associated with a higher risk of recurrence than that of lobectomy; we evaluated the factors considered to be predictors of recurrence.

METHODS

By analyzing multicenter prospective studies of sublobar resection for patients with c-stage I non-small lung cancer who were unable to undergo lobectomy (KLSG-0801), we investigated the relationship between (1) tumor location (TL) and margin distance from the stump (MD), (2) the MD/tumor size (TS) ratio and prognosis, (3) and the margin cytology (MC) and prognosis.

RESULTS

The correlation between TS and MD was statistically significant in cases of easily resectable regions defined by Lewis' classification (n = 18). However, there was no correlation in difficult-to-resect regions (n = 14). Among cases of recurrence, the MD/TS ratio was less than 1. The 3-year survival rate was 100% for patients with MD/TS > 1 (n = 12), 59.7% for patients with MD/TS ≤ 1 (n = 20) (p = 0.06), 88.1% in cases of negative MC (n = 18), and 20% in cases of positive MC (n = 5) (p = 0.001).

CONCLUSION

Cases with positive MC had a significantly worse prognosis than those with negative MC. It may be difficult to secure an MD greater than the TS in a difficult-to-resect region according to Lewis' classification.

[Progress of Lung Margin During Sublobar Resection for Early-staged Non-small Cell Lung Cancer]

近年来随着低剂量计算机断层扫描(low-dose computed tomography, LDCT)、高分辨率CT(high-resolution CT, HRCT)的普及, 早期非小细胞肺癌的发现比率不断上升, 越来越多的胸外科医生探索手术方式的改良, 推动手术切除范围向更加合理的方向进展。临床研究发现肺切缘阴性较阳性有更低的局部肿瘤复发率, 因此亚肺叶切除术治疗早期肺癌术中保证肺切缘阴性具有重要的临床意义, 本文将就这一领域研究现状和进展作一综述。

Validating margin status in lung wedge resection for clinical stage I non-small cell lung cancer

Stage I non-small cell lung cancer (NSCLC) is a localized disease without metastasis; therefore, it can be treated effectively with local therapies. Pulmonary resection is the most frequent treatment, performed as pulmonary wedge resection, segmentectomy, lobectomy, or pneumonectomy. Some retrospective clinical studies of pulmonary wedge resection suggest that its outcome may be inferior to that of anatomical pulmonary resection, whereas other recent studies, which assess surgical margin status, leveled acceptable outcomes. Since the outcome of pulmonary wedge resection for lung cancer may depend on tumor size, distance from the surgical margin to the tumor, tumor size/margin distance ratio, and margin cytology results, a prospective study assessing these parameters is ongoing. This will allow us to identify the clinical implications of these factors and predict which patients are likely to have a good outcome.

Detection of oncogenic mutations in resected bronchial margins by next-generation sequencing indicates early relapse in stage IA lung adenocarcinoma patients

Stage I non-small cell lung cancer (NSCLC) patients experience a relatively high rate of recurrence, ranging from about 30-35%. We hypothesized that this elevated risk of recurrence is due to the presence of tumor cells at bronchial margins which was undetected by conventional light microscopy. Patients with clinical stage IA (T1N0M0) NSCLC were enrolled in this study, which included 8 early-relapse(ER) and 6 no-relapse(NR) patients. Primary tumor, bronchial margin, and normal lung tissues were collected and sent to a central site for targeted next-generation sequencing analysis. All of the patients were lung adenocarcinoma. Gene mutations were identified in all tumor tissue samples (100%). Oncogenic mutations were identified in 87.5%(7/8) bronchial margins of early relapse patients, whereas only 16.7%(1/6) no-relapse (NR) patient of marginal tissue had identified gene mutation. Additionally, concordance between primary tumor and bronchial margins was relatively high, with 4 of 8 (50%) ER patients having at least one identical mutation. Moreover, according to the gene mutation status in marginal tissue, 87.5% (7/8) of patients with at least one gene mutation in the bronchial margins had local recurrence or metastasis, whereas only 16.7% (1/6) of patients without any mutation detected had signs of relapse, the recurrence rate was significantly higher than that of the negative mutation margin group ((p (log-rank) = 0.023). The existence of oncogenic mutations in bronchial margins may represent occult residual tumor and elevated risk of recurrence in early stage NSCLC patients. Thus, assessing molecular status in bronchial margins may help identify patients who might benefit from extensive surgery or adjuvant treatment.

Pulmonary adenocarcinoma possibly developed from the cut-end of small-sized adenocarcinoma in the lung periphery as recurrence 13 years after its wedge resection

Background

It is a big topic for general thoracic surgery whether still curability can be obtained by limited resection for peripheral small-sized nodules of non-small cell lung cancer (NSCLC) in the current era of frequent computed tomography (CT) use. Accumulation of information on problematic cases would be meaningful for surgeons to select better surgical procedures.

Case presentation

A 69-year-old man was pointed out an enlarged 2.1-cm solid nodule on the edge of staple line of the residual right upper lobe by chest CT. He had past history of the lung cancer surgery, wedge resection of the same right upper lobe 13 years ago. The pathological findings were 1.1-cm, p-TlbN0M0, p-stage IA2-adenocarcinoma. Thereafter, he received no adjuvant therapy. This time, the trans-bronchial lung biopsy revealed adenocarcinoma. After the completion lobectomy of the residual right upper lobe, the tumor was diagnosed as adenocarcinoma consistent with recurrence of small-sized adenocarcinoma in the lung periphery developed from the cut-end because of similarities between present and previous tumors on histopathology and p53-positivity.

Conclusions

When limited resection has been performed for small-sized NSCLC presenting solid nodule on thin-slice CT images, long-term postoperative follow-up time will be necessary for monitoring, considering the possibility of cut-end recurrence.

A no-touch technique for pulmonary wedge resection of lung cancer

OBJECTIVE

Many of the surgical patients with lung cancer die by metastasis originated from circulating tumor cells (CTCs) which are seeds of metastases. A ring-shaped catching forceps, which generates the great pressure by compression, may reduce the risk of tumor cell spreading. Here, we investigated the efficacy of such forceps based on CTC occurrence.

METHODS

Twenty-three patients with clinical stage IA lung cancer who underwent a pulmonary wedge resection were investigated in a clinical-pathological manner. They were divided into those treated using ring forceps catching without tumor release (R group) (n = 16) and non-complete use of ring forceps (N group) (n = 7), then were determined circulating tumor cells (CTCs).

RESULTS

Radiographic findings, tumor location, pathological diagnosis, and stapling method were not significantly different between the groups. The risk of detection of CTCs after surgery was significantly lower in group R (12.5 vs. 85.7%, p = 0.02), whereas there were no significant differences found in risk of negative-stapled margin cytology, pre-OP CTC detection, V (+), Ly (+), and Pl (+).

CONCLUSIONS

Patients who underwent pulmonary wedge resection of lung cancer had low chance of CTC detection after surgery when they were treated with ring forceps without tumor release, which might become a no-touch isolation technique.

The Impact of Margins on Outcomes After Wedge Resection for Stage I Non-Small Cell Lung Cancer

BACKGROUND

The relationship between margin distance and recurrence and survival for stage I non-small cell lung carcinoma (NSCLC) less than or equal to 2 cm is not clear.

METHODS

Patient clinicopathologic data were reviewed from a pooled data set of stage I NSCLC lesions less than or equal to 2 cm resected by wedge resection at Brigham and Women's Hospital (BWH) between 2000 and 2005 and the International Early Lung and Cardiac Action Program (I-ELCAP) between 1999 and 2015. Multivariable models were constructed to evaluate the relationship between margin distance and recurrence and survival, adjusting for patient age, sex, tumor size, and histologic type. Optimal margin distance was determined for recurrence-free and overall survival using maximum χ² values among survival distributions.

RESULTS

Of 182 cases, 138 tumors had margin distance reported (113 BWH and 25 I-ELCAP). The average tumor size was 13.3 mm, and margin distance was 8.3 mm. During a mean follow-up of 49.6 months, there were 33 recurrences and 59 deaths. Increased margin distance was independently associated with lower risk of recurrence (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.83-0.98). Margin distance was also independently associated with longer survival (hazard ratio [HR], 0.94; 95% CI, 0.90-0.98). A margin distance greater than 9 mm was associated with longest recurrence-free survival and a margin distance greater than 11 mm was associated with longest overall survival.

CONCLUSIONS

Increased margin distance was independently associated with lower risk of recurrence and longer overall survival in patients undergoing wedge resection for NSCLC tumors less than or equal to 2 cm. These findings suggest that with a minimum appropriate margin distance, wedge resection may yield outcomes comparable to those of lobectomy.

Challenges of Frozen Section in Thoracic Pathology: Lepidic Lesions, Limited Resections, and Margins

CONTEXT

- The use of frozen section in thoracic pathology includes assessment of peripheral lung lesions with lepidic pattern, with greater emphasis on evaluating lung-sparing resections and margin assessment.

OBJECTIVE

- To review pitfalls of frozen section in thoracic pathology; in this setting, reduction of false-positive and false-negative diagnosis in lesion identification and margin assessment is critical.

DATA SOURCES

- PubMed search of frozen section lung pathology yielded specific references related to the use of frozen section in the identification of lepidic lesions and the clinical recommendation for margin distance.

CONCLUSIONS

- Frozen section diagnosis is overall accurate in assessment of lepidic lesions. Pitfalls include rare benign mimickers and more common reactive lesions. Standard approaches to gross assessment and margin measurement require further research with increasing use of lung-sparing resections.

Prognostic value of molecular events from negative surgical margin of non-small-cell lung cancer

It is hypothesized that the molecular status in negative surgical margin (NSM) is associated with prognosis of cancer patients. In this study, the prognostic relevance of Epithelial-to-Mesenchymal Transition (EMT) molecular events in NSMs in patients with NSCLC was investigated. EMT model was developed, in which the mesenchymal transition of human immortalized bronchial epithelial cell line was induced by TGF-beta1. Gene expression of EMT-induced cells and NSMs from 60 lung squamous cell carcinoma (SCC) patients was profiled by microarray and validated by quantitative RT-PCR. Two independent cohorts (lung SCC, n = 50; NSCLC, n = 54) were employed to validate the prognostic value of candidate genes. A set of 1490 genes were identified in EMT model in vitro. An EMT-like gene-expression pattern by 33 essential genes was optimized in NSMs, and was significantly associated with tumor progression. The 33 genes also exhibited a site-dependent field cancerization effect in the normal-appearing airways adjacent to NSCLCs. In the independent lung SCC cohort, the EMT-like active pattern indicated poor outcome of patients (n = 50, log-rank p = 0.009). Furthermore, in the NSCLC cohort, patients with EMT-like active pattern had shorter predictive survival time (n = 54, log-rank p = 0.02). In conclusion, the existence of EMT-like gene expression in NSMs, may play critical role in tumor progression and be a potential biomarker for prognosis in patients with NSCLC.

Multicenter prospective study of sublobar resection for c-stage I non-small cell lung cancer patients unable to undergo lobectomy (KLSG-0801): complete republication

BACKGROUND

Local therapy for stage I non-small cell lung cancer (NSCLC) is divided into surgical and radiation treatment, and given to patients unable to tolerate a lobectomy. A prospective phase II study of cases that received stereotactic body radio therapy (SBRT) (JCOG0403) revealed an overall 3-year survival rate (3-YSR) of 76.0 %, 3-year relapse free survival rate (3-YRFS) of 69.0 %, and rate of morbidity of grade 3 or greater of 9 %. However, few prospective multicenter studies have reported regarding surgery for high-risk stage I NSCLC patients.

METHODS

We investigated this issue in the setting of a prospective multicenter observational study. Thirty-two high-risk NSCLC patients (30 males, 2 females; median age 74 years, 61-85 years) were analyzed.

RESULTS

Two (6.3 %) showed morbidity of grade 3 or greater, though there were no postoperative deaths. The margin local control rate was 97.0 % (surgical margin recurrence, 1) and local recurrence control rate was 75.0 % (ipsilateral thorax recurrence, 8), while the 3-YSR and 3-YRFS was 79.0 and 75.9 %, respectively.

CONCLUSION

A sublobar pulmonary resection for patients unable to tolerate a lobectomy with stage I NSCLC was shown to be safe and provided results comparable with those of SBRT.

Clinical implications of positive margins following non-small cell lung cancer surgery

Positive margins following pulmonary resection of non-small cell lung cancer (NSCLC) occur in approximately 5-15% of patients undergoing a curative procedure. The presence of positive margins negatively impacts long-term outcomes by setting the stage for local and potentially distant disease recurrence. Despite major clinical ramifications, there are very few dedicated reports that examine the implications of positive margins following surgery for NSCLC. Furthermore, published series are typically retrospective studies from single institutions. In this review we analyze published data with special consideration of four pertinent questions: (i) what are the long term outcomes of a positive margin following pulmonary resection?, (ii) is intraoperative margin assessment by frozen section reliable?, (iii) what is the optimal distance of the tumor margin to the surgical margin?, and (iv) should adjuvant chemotherapy and/or radiation therapy be used in the setting of a positive surgical margin?

Lung excision of non-small-cell lung cancer leaves cancer cells in residual lobe: cytological detection using pulmonary vein blood

OBJECTIVES

Lung excision to treat non-small-cell lung cancer (NSCLC) is associated with a worse prognosis when compared with a lobectomy. Cancer relapse may be caused by tumour cells remaining in the residual lobe, the possibility of dislodged cancer cells in the residual lobe is assessed using pulmonary vein blood (PVB) from the resected lung.

METHODS

Twenty-eight patients with pathological stage I NSCLC who underwent lung excision followed by a lobectomy were evaluated according to the status of isolated tumour cells (ITCs) (origin of circulating tumour cells) in PVB from the resected lobe. Survival was also assessed according to the status of ITCs.

RESULTS

The rate of ITC presence was 60.7% and depended on margin distance/tumour size (M/T) with a threshold of 1.0-30.8% (4/13) in M/T greater than or equal to 1.0 and 86.7% (13/15) in M/T smaller than 1.0 (P = 0.001). PVB-ITC status was no ITCs (N) in 11 (39.3%), only singular cells (S) in 13 (50.0%) and clustered cells (C) in 4 (14.3%). In addition, the survival status of patients with clustered cells was exclusively wrong.

CONCLUSION

After pulmonary excision for lung cancer, tumour cells remain in the residual lobe and the morphology of which may indicate recurrence.

Adjuvant chemotherapy and radiotherapy in the treatment of non-small cell lung cancer (NSCLC)

Lung cancer is one of the most common human malignancies and remains the leading cause of cancer related deaths worldwide. Many recent technological advances led to improved diagnostics and staging of lung cancer. With development of new treatment options such as targeted therapies there might be improvement in progression free survival of patients with advanced stage non-small cell lung cancer (NSCLC). Improvement in overall survival is still reserved for selected patients and selected treatments. One of the mostly investigated therapeutic options is adjuvant treatment. There are many open issues in selection of patients and administration of appropriate adjuvant treatment.

Relationship between margin distance and local recurrence among patients undergoing wedge resection for small (≤2 cm) non-small cell lung cancer

OBJECTIVE

Successful pulmonary wedge resection for early-stage non-small cell lung cancer requires a pathologically confirmed negative margin. To date, however, no clear evidence is available regarding whether an optimal margin distance, defined as the distance from the primary tumor to the closest resection margin, exists. Toward addressing this gap, we investigated the relationship between the margin distance and local recurrence risk.

METHODS

We reviewed all adult patients who had undergone wedge resection for small (≤2 cm) non-small cell lung cancer from January 2001 to August 2011, with follow-up through to December 31, 2011. The exclusion criteria included other active noncutaneous malignancies, bronchoalveolar carcinomas, lymph node or distant metastases at diagnosis, large cell cancer, adenosquamous cancer, multiple, multifocal, and/or metastatic disease, and previous chemotherapy or radiotherapy. Using Cox regression analysis, we examined the relationship between the margin distance and interval to local recurrence, adjusting for chronic obstructive pulmonary disease, forced expiratory volume in 1 second, smoking, diabetes, tumor size, tumor location, surgeon, open versus video-assisted thoracoscopic surgery, and whether the lymph nodes were sampled.

RESULTS

Of 557 consecutive adult patients, 479 met our inclusion criteria. The overall, unadjusted 1- and 2-year local recurrences rate was 5.7% and 11.0%, respectively. From the adjusted analyses, an increased margin distance was significantly associated with a lower risk of local recurrence (P = .033). Patients with a 10-mm margin distance had a 45% lower local recurrence risk than those with a 5-mm distance (hazard ratio, 0.55; 95% confidence interval, 0.35-0.86). Beyond 15 mm, no evidence of additional benefit was associated with an increased margin distance.

CONCLUSIONS

In wedge resection for small non-small cell lung cancer, increasing the margin distance ≤15 mm significantly decreased the local recurrence risk, with no evidence of additional benefit beyond 15 mm.

Potential errors in staging primary pulmonary adenocarcinomas by sublobar resection

INTRODUCTION

There is increasing interest in treating patients with stage I pulmonary adenocarcinoma with sublobar resection and staging lymphadenectomy (StLN), but there is no information on the potential impact of this approach on staging.

METHODS

A total of 241 consecutive wedge resections followed by immediate completion lobectomy (n = 225), bilobectomy (n = 3), or trisegmentectomy (n = 13) ("second specimens") and StLN were retrieved from our database. Tumor location, size, pT, and distance to closest margin (D) in the wedge specimens were compared with the presence of residual and/or additional tumor nodules in the lung and metastatic tumor in N1 lymph nodes of the "second specimens."

RESULTS

Residual tumor (n = 14), additional tumor nodules (n = 9), and both (n = 1) were present in the lung parenchyma of 24 "second specimens." Problems orienting residual tumor to tumor in the wedge made it difficult to accurately determine overall tumor size and final pT in some cases. In 10 of the 241 cases, metastatic tumor was present only in N1 lymph nodes in the "second specimen."

CONCLUSIONS

Sublobar resections with StLN would have potentially understaged 19 (7.9%) of 241 patients (9 as pT1 or pT2 instead of pT3, 9 as pN0 instead of pN1, and 1 as pT1N0 instead of pT3N1). Preoperative positron emission tomography/computed tomography suggested the presence of more than 1 parenchymal tumor nodule and/or metastatic tumor in N1 lymph nodes of the "second specimen" in only 5 of these cases. Sublobar resections may miss additional tumor nodules and positive lymph nodes and understage a small proportion of pulmonary adenocarcinoma patients.