Skip metastasis to the mediastinal lymph nodes in non-small cell lung cancer

Relationship between postoperative nodal skip metastasis of mid-thoracic esophageal squamous cell carcinoma and patient prognosis and its value in guiding postoperative adjuvant treatment

Objective

To evaluate the predictive role of nodal skip metastasis (NSM) in the prognosis of lymph node-positive mid-thoracic esophageal squamous cell carcinoma, and to evaluate the significance of postoperative adjuvant treatment in patients with different sites of metastatic nodes.

Methods

A retrospective analysis was performed on clinical data of 321 lymph node-positive mid-thoracic esophageal squamous cell carcinoma patients who underwent surgery in the Fourth Hospital of Hebei Medical University. Based on the site and condition of lymph node metastasis by postoperative pathology, the patients were divided into two groups: NSM group and non-NSM (NNSM) group. The propensity score matching (PSM) method was employed to match the two groups. The prognostic factors of patients before and after PSM as well as the effect of different adjuvant treatment modes on the prognosis of patients before and after PSM were analyzed. SPSS 29.0 statistical software was used for analysis.

Results

PSM in a 1 : 1 matching ratio was performed, 103 patients were assigned to NSM group and NNSM group respectively. Significant differences were found in the 3- and 5-year OS and DFS between the two groups before PSM, the 3- and 5-year OS also showed a significant difference after PSM (P < 0.05). Multivariate analysis illustrated that gender, postoperative adjuvant treatment mode, N stage and lymph node metastasis were independent risk factors for OS and DFS after PSM (P < 0.05); for NSM patients, postoperative adjuvant chemotherapy and radiotherapy significantly prolonged OS and DFS before and after PSM (P < 0.05). But no significant difference was found in OS and DFS for NNSM patients after PSM (P > 0.05).

Conclusion

Postoperative NSM is a good prognostic factor for patients with mid-thoracic esophageal squamous cell carcinoma, postoperative adjuvant chemoradiotherapy was recommended for those group, thereby gaining survival benefits.

Potential factors of cytokeratin fragment 21-1 and cancer embryonic antigen for mediastinal lymph node metastasis in lung cancer

Objective: Lung cancer is a common malignant tumor, characterized by being difficult to detect and lacking specific clinical manifestations. This study aimed to find out the risk factors of mediastinal lymph node metastasis and explore the correlation between serum tumor markers and mediastinal lymph node metastasis and lung cancer prognosis.

Methods: A retrospective study of 3,042 lung cancer patients (330 patients with mediastinal lymph node metastasis and 2,712 patients without mediastinal lymph node metastasis) collected from the First Affiliated Hospital of Nanchang University from April 1999 to July 2020. The patients were divided into two groups, namely, mediastinal lymph node metastasis group and non-mediastinal lymph node metastasis group. Student’s t test, non-parametric rank sum test and chi-square test were used to describe whether there is a significant difference between the two groups. We compared the serum biomarkers of the two groups of patients, including exploring serum alkaline phosphatase (ALP), calcium hemoglobin (HB), alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), CA125, CA-199, CA -153, cytokeratin fragment 19 (CYFRA 21-1), total prostate specific antigen (TPSA), neuron-specific enolase (NSE) levels and the incidence and prognosis of lung cancer mediastinal lymph node metastasis. Binary logistic regression analysis was used to determine its risk factors, and receiver operating curve (ROC) analysis was used to evaluate its diagnostic value for mediastinal lymph node metastasis.

Results: Binary logistic regression analysis showed that carcinoembryonic antigen and CYFRA 21-1 were independent risk factors for mediastinal lymph node metastasis in patients with lung cancer (p < 0.001 and p = 0.002, respectively). The sensitivity and specificity of CEA for the diagnosis of mediastinal lymph node metastasis were 90.2 and 7.6%, respectively; CYFRA 21-1 were 0.6 and 99.0%, respectively.

Conclusion: Serum CEA and CYFRA 21-1 have predictive value in the diagnosis of mediastinal lymph node metastasis in patients with lung cancer.

The Impact of Skip vs. Non-Skip N2 Lymph Node Metastasis on the Prognosis of Non-Small-Cell Lung Cancer: A Systematic Review and Meta-Analysis

Objective: The skip N2 metastases were frequent in non-small-cell lung cancer (NSCLC) and the better prognosis of NSCLC with a skip over non-skip N2 lymph node metastases is controversial. The primary aim of this study is to investigate the prognosis effect of skip N2 lymph node metastases on the survival of NSCLC.

Setting: A literature search was conducted in PubMed, EMBASE, and Cochrane Library with the term of “N2” or “mediastinal lymph node” or “mediastinal nodal metastases”, and “lung cancer” and “skip” or “skipping” in the title/abstract field. The primary outcomes of interests are 3- and 5-year survival in NSCLC.

Participants: Patients who underwent complete resection by lobectomy, bilobectomy, or pneumonectomy with systemic ipsilateral lymphadenectomy and were staged as pathologically N2 were included.

Primary and Secondary Outcome Measures: The 3- and 5-year survival of NSCLC was analyzed. The impact of publication year, number of patients, baseline mean age, gender, histology, adjuvant therapy, number of skip N2 stations, and survival analysis methods on the primary outcome were also analyzed.

Results: A total of 21 of 409 studies with 6,806 patients met the inclusion criteria and were finally included for the analysis. The skip N2 lymph node metastases NSCLC had a significantly better overall survival (OS) than the non-skip N2 NSCLC [hazard ratio (HR), 0.71; 95% CI, 0.62–0.82; P < 0.001; I² = 40.4%]. The skip N2 lymph node metastases NSCLC had significantly higher 3- and 5-year survival rates than the non-skip N2 lymph node metastases NSCLC (OR, 0.75; 95% CI, 0.66–0.84; P < 0.001; I² = 60%; and OR, 0.78; 95% CI, 0.71–0.86; P < 0.001; I² = 67.1%, respectively).

Conclusion: This meta-analysis suggests that the prognosis of skip N2 lymph node metastases NSCLC is better than that of a non-skip N2 lymph node.

Metastatic Patterns of Mediastinal Lymph Nodes in Small-Size Non-small Cell Lung Cancer (T1b)

Background: Lymph node metastasis (LNM) status is critical to the treatment. Fewer studies has focused on LNM in patients with small-size non-small cell lung cancer (NSCLC). This study aims to investigate clinicopathological characteristics associated with skip N2 (SN2) and non-skip N2 (NSN2) metastasis, and their metastatic patterns in NSCLC with tumor size of 1–2 cm.

Methods: We reviewed the records of NSCLC patients with tumor size of 1–2 cm who underwent lobectomy with systematic lymph node dissection (LND) between January 2013 and June 2019. Clinical, radiographical, and pathological characteristics were compared among N1, SN2, and NSN2 groups. Metastatic patterns of mediastinal lymph node were analyzed based on final pathology.

Results: A total of 63 NSCLC patients with tumor size of 1–2 cm were staged as pN2, including 25 (39.7%) SN2 and 38 (60.3%) NSN2. The incidence rates of SN2 and NSN2 were 2.8% (25/884) and 4.3% (38/884), respectively. For all clinicopathological characteristics, no significant difference was observed among the groups of N1, SN2, and NSN2. For the tumor located in each lobe, specific nodal drainage stations were identified: 2R/4R for right upper lobe; 2R/4R and subcarinal node (#7) for right middle lobe and right lower lobe; 4L and subaortic node (#5) for left upper lobe; #7 for left lower lobe. However, there were still a few patients (10.9%, 5/46) had the involvement of lower zone for tumors of upper lobe and the involvement of upper zone for lower lobe.

Conclusions: SN2 occurs frequently in patients with small-size NSCLC. Whether lobe-specific selective LND is suitable for all small-size patients deserves more studies to confirm. Surgeons should be more careful when performing selective LND for tumors located in the lower and upper lobes.

Skip N2 Metastasis in Pulmonary Adenocarcinoma: Good Prognosis Similar to N1 Disease

INTRODUCTION

The prognostic effect and mechanism of skip N2 lung cancer remain unclear. Our study aimed to elucidate the influence of skip N2 on overall survival (OS) and disease-free survival (DFS) compared with N1 and non-skip N2 in patients with lung adenocarcinoma.

PATIENTS AND METHODS

Patients with lung adenocarcinoma and lymph node involvement between May 2011 and December 2015 were retrospectively analyzed. The outcomes of skip N2 patients were compared with N1 and non-skip N2 patients. Prognosis was further investigated according to the N status in different adenocarcinoma subtypes. Univariate and multivariate analyses were carried out to define independent risk factors for OS and DFS.

RESULTS

A total of 456 patients with lung adenocarcinoma, 169 with N1 disease, 81 with skip N2 disease, and 206 with non-skip N2 disease, were enrolled in this study. All tumors were invasive adenocarcinoma, and the predominant subtypes were acinar in 252, papillary in 42, solid in 119, micropapillary in 20, and invasive mucinous adenocarcinoma in 23 patients. The DFS and OS of N1 and skip N2 diseases were similar and significantly better than those of patients with non-skip N2 disease. The prognosis according to lymph node status was significantly different in acinar-predominant subtypes in terms of both OS and DFS.

CONCLUSIONS

Skip N2 disease has a similar prognosis to N1 disease and is significantly better than that of non-skip N2 disease in relation to OS and DFS. Skip N2 has a prognostic advantage in patients with the acinar-predominant subtype.

Near-infrared imaging and optical coherence tomography for intraoperative visualization of tumors

Surgical excision is the foundation of treatment for early-stage solid tumors in man and companion animals. Complete excision with appropriate margins of surrounding tumor-free tissue is crucial to survival. Intraoperative imaging allows real-time visualization of tumors, assessment of surgical margins, and, potentially, lymph nodes and satellite metastatic lesions, allowing surgeons to perform complete tumor resections while sparing surrounding vital anatomic structures. This Review will focus on the use of near-infrared imaging and optical coherence tomography for intraoperative tumor visualization.

Single-station skip-N2 disease: good prognosis in resected non-small-cell lung cancer (long-term results in skip-N2 disease)

OBJECTIVES

Pathological N2 (pN2) involvement has a negative impact on prognosis in patients operated on due to non-small-cell lung cancer (NSCLC). pN2 disease may cause skip (pN0N2) or non-skip (pN1N2) metastases with pathological N1 (pN1) involvement. The effect of pN2 subgroups on prognosis is still controversial. We analysed the effect of pN1 disease and single-station pN2 disease subgroups on survival outcomes.

METHODS

The medical records of patients who underwent anatomical lung resection due to NSCLC at a single centre between January 2007 and January 2017 were prospectively collected and retrospectively analysed. Operative mortality, sublobar resection, Stage IV disease, incomplete resection and carcinoid tumour were considered exclusion criteria. After histopathological examination, the prognosis of patients with pN1, pN0N2 and pN1N2 was compared statistically. Univariable and multivariable analyses were made to define independent risk factors for overall survival rates.

RESULTS

The mean follow-up time for 358 patients with 228 pN1 disease (63.7%), 59 pN0N2 disease (16.5%) and 71 pN1N2 disease (19.8%) was 40.4 ± 30.4 months. Median and 5-year overall survival rates for pN1, pN0N2 and pN1N2 diseases were 73.6 months [95% confidence interval (CI) 55.5-91.7] and 54.1%, 60.3 months (95% CI 26.8-93.8) and 51.2%, 20.8 months (95% CI 16.1-25.5) and 21.5%, respectively. The survival CIs of pN1 and pN0N2 diseases were similar, and the survival rates of these 2 groups were significantly better than those with pN1N2 (P < 0.001, P = 0.001, respectively). In multivariable analysis, patients over the age of 60 [hazard ratio (HR) 2.13, P < 0.001], patients not receiving adjuvant therapy (HR 1.52, P = 0.01) and patients with pN1N2 disease (HR 2.91, P < 0.001) had a poor prognosis.

CONCLUSIONS

Advanced age, not receiving adjuvant therapy and having pN1N2 disease are negative prognostic factors in patients with nodal involvement who underwent curative resection due to NSCLC. The overall survival and recurrence-free survival rates of pN1 disease and single-station pN0N2 disease are similar, and they have significantly better survival rates than pN1N2 disease. Based on these results, surgical treatment may be considered an appropriate choice in patients with histopathologically diagnosed single-station skip-N2 disease.

Role of Skip Mediastinal Lymph Node Metastasis for Patients With Resectable Non-small-cell Lung Cancer: A Propensity Score Matching Analysis

BACKGROUND

N2 disease represents a heterogeneous group of non-small-cell lung cancer (NSCLC) with varying 5-year overall survival (OS) rates. The skip N2 phenomenon is quite frequent, and its prognostic impact remains a matter of debate. The aim of this study is to further assess the clinical significance and prognostic value of skip N2 disease using propensity score matching.

PATIENTS AND METHODS

The study cohort included 437 patients with stage pN2 NSCLC who underwent resection from 2005 to 2011. Differences in clinicopathologic characteristics were identified in the overall cohort. The effect of skip N2 on OS was assessed, stratified by histology, tumor size, N2 involved stations, and T stage after propensity score matching.

RESULTS

A total of 130 patients had skip N2 diseases in our study. Skip N2 metastasis was associated with age, tumor size, histology, and number of involved N2 stations. Matching of 130 pairs of patients showed that skip N2 was associated with a significantly better 5-year OS rate when compared with non-skip N2 disease (42.7% vs. 25.3%; P = .004), and OS is significantly better in the patients with tumor size of ≤ 3 cm (P = .014) or patients with single N2 station involvement (P = .002). Skip N2 conferred a significantly better OS in stage IIIA (P = .026) and IIIB (P = .029) disease.

CONCLUSION

The presence of skip N2 metastasis was a good prognostic factor of resectable N2 disease. N2 disease may be classified into more subgroups in the revision of the current tumor-lymph node-metastasis (TNM) system.

Intraoperative fluorescence imaging in thoracic surgery

Intraoperative fluorescence imaging (IFI) can improve real-time identification of cancer cells during an operation. Phase I clinical trials in thoracic surgery have demonstrated that IFI with second window indocyanine green (TumorGlow^® ) can identify subcentimeter pulmonary nodules, anterior mediastinal masses, and mesothelioma, while the use of a folate receptor-targeted near-infrared agent, OTL38, can improve the specificity for diagnosing tumors with folate receptor expression. Here, we review the existing preclinical and clinical data on IFI in thoracic surgery.

Clinical significance of skipping mediastinal lymph node metastasis in N2 non-small cell lung cancer

Background

Lymph node metastasis is critical for the prognosis of non-small cell lung cancer (NSCLC) patients, and understanding of the pattern of lymph node metastasis is key to the treatment. We aim to investigate the N2 NSCLC patients without N1 lymph node involvement.

Methods

From 1999 to 2005, a total of 803 patients with pN2 NSCLC were enrolled in this study. Among them, 137 pN2 patients with no metastasis at the hilar (N1) lymph nodes [skip (+) group] were compared with the other 666 patients [skip (-) group].

Results

The percentage of male, smoker and squamous cell carcinoma patients were significantly higher in the skip (+) group, (83.21% vs. 64.11%, P<0.001; 76.64% vs. 53.60%, P<0.001; 50.36% vs. 37.54%, P=0.007, respectively). Also, the primary tumor of skip (+) group patients were significantly more often located in the right upper and middle lobe (43.07% vs. 23.42%, 10.95% vs. 4.05%, P=0.001), and metastasis more frequently involved one lymph node station (75.18% vs. 49.55%, P<0.001). There was no significant difference in the number of total and N2 lymph node dissected. The postoperative survival of patients in both groups were also similar (P=0.379).

Conclusions

Skipping mediastinal lymph node metastasis happens in about 17% of NSCLC patients with mediastinal lymph nodes metastasis but it is not a prognostic factor.

Parathyroid adenoma upstaging the lung cancer

Mediastinal staging of NSCLC with noninvasive methods such as PET/CT can be misleading when a mediastinal disease accompany. Histopathologic confirmation should be made before any treatment plan. Herein, we presented a case of parathyroid adenoma upstaging the lung cancer.

The clinicopathological features associated with skip N2 metastases in patients with clinical stage IA non-small-cell lung cancer

OBJECTIVES

Understanding the clinicopathological features of patients with skip N2 metastases (SN2) in clinical early stage lung cancer is important for surgical planning and other treatment considerations; however, the factors associated with SN2 are unclear. This study aimed to investigate the clinicopathological features associated with SN2 in patients with clinical stage IA (cIA) non-small-cell lung cancer (NSCLC).

METHODS

We retrospectively studied patients with cIA NSCLC who underwent pulmonary resection (at least lobectomy) and extensive lymphadenectomy (more than ND2a-1) at our institution between January 2004 and December 2010. We investigated the following factors for their association with SN2: age; sex; tumour marker (carcinoembryonic antigen); tumour size on computed tomography (CT), evaluated with a lung-window (LW) and a mediastinal-window (MW) setting; pathology, with or without adenocarcinoma; differentiation; visceral pleural invasion (VPI) and vascular/lymphatic invasion.

RESULTS

In total, 422 patients were enrolled, with the following pathological node (pN) statuses: 331 pN0 (78.4%), 39 pN1 (9.3%) and 52 pN2 (12.3%). There were 21 (23.1%) SN2 cases among the patients with nodal metastases. When the cut-off level was defined as a receiver operating characteristic curve with MW (11.5 mm), the sensitivity and specificity of SN2 was 95.2% and 42.9%, respectively. VPI was a statistically independent relevant factor for SN2 in both the patients with cIA and in those with nodal involvement. The VPI classification comprised 59 PL-0 (64.8%), 12 PL-1 (13.2%) and 20 PL-2 (22.0%) with nodal metastases, and there was a significant difference between the three groups (P = 0.03) according to SN2 frequency. There was no difference between VPI 1 and 2 (P = 0.27).

CONCLUSIONS

In conclusion, our study suggests that the incidence of SN2 is significantly associated with VPI in patients with cIA NSCLC. Although MW (>11.5 mm) had a low specificity in the assessment of SN2, it had a high sensitivity, suggesting the possibility of a superior benefit compared with LW. Standard hilar and mediastinal lymph node dissection should be required in patients with suspicious VPI and MW (>11.5 mm) on preoperative CT.

Pattern of metastasis outside tumor-bearing segments in primary lung cancer: rationale for segmentectomy

BACKGROUND

Patterns of intrapulmonary metastasis, particularly metastasis outside tumor-bearing segments, were investigated in lung cancer patients to address the rationale for segmentectomy.

METHODS

In a consecutive series of patients who underwent resection of two or more pulmonary segments for primary lung cancer, intrapulmonary spread patterns, such as segmental/intersegmental node metastasis and pulmonary parenchymal metastasis, were pathologically examined.

RESULTS

Eligible 244 lesions included 167 adenocarcinomas, 66 squamous cell carcinomas, and 11 large cell carcinomas. Pathologic stages included 0 to IA (n=111), IB (n=56), IIA (n=31), IIB (n=20), IIIA (n=23), and IIIB to IV (n=3); and N1 (n=26) and N2 (n=22). Intrapulmonary spread was observed in 24 cases (9.8%). Of these, metastasis outside tumor-bearing segments was only observed in 4 cases (1.6%), and such cancer spread was more frequently seen in cases with extrapulmonary (hilar to mediastinal) nodal metastasis (7.9%) than in cases without extrapulmonary metastasis (0.5%; p=0.01). Metastasis outside tumor-bearing segments was not observed in 64 tumors with pure or mixed ground glass opacity features on computed tomography. Although tumor location (peripheral or central/intermediate) was not related to the incidence of metastasis outside tumor-bearing segments, intrapulmonary spread was observed in only 1 of 52 peripheral small (≤20 mm) tumors.

CONCLUSIONS

Metastasis outside tumor-bearing segments is rarely observed in cases with tumors (1) without extrapulmonary nodal metastasis and (2) with ground glass opacity or peripheral small (≤20 mm) features.

The role of segmental nodes in the pathological staging of non-small cell lung cancer

Background

Segmental nodes are not examined routinely in current clinical practice for lung cancer, the role of segmental nodes in pathological staging of non-small cell lung cancer after radical resection was investigated.

Methods

A total of 113 consecutive non-small cell lung cancer patients who underwent radical resection between June 2009 and December 2011 were retrospectively reviewed. All the operations were performed by the same group of surgeons. N2 nodes, hilar nodes, interlobar nodes and some lobar nodes were collected during surgery. The removed lung lobes were dissected routinely along lobar and segmental bronchi to collect lobar nodes and segmental nodes. The collected lymph nodes were separately labeled for histological examination.

Results

The detection rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 61.1%, 85.0%, 75.2% and 80.5%, respectively. The metastasis rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 5.3%, 10.5%, 16.8% and 14.2%, respectively. There were 68 cases of N0 disease, 16 cases of N1 disease and 29 cases of N2 disease. If an analysis of segmental lymph nodes had been omitted, six patients (37.5% of N1 disease) would have been down-staged to N0, and two cases of multiple-zone N1 disease would have been misdiagnosed as single-zone N1 disease, one patient would have been misdiagnosed as N2 disease with skip metastases.

Conclusion

Segmental nodes play an important role in the accurate staging of non-small cell lung cancer, and routinely dissecting the segmental bronchi to collect the lymph nodes is feasible and may be necessary.

Analysis of factors influencing skip lymphatic metastasis in pN(2) non-small cell lung cancer

OBJECTIVE

Although many clinical studies on skip lymphatic metastasis in non-small cell lung cancer have been reported, the risk factors for skip lymphatic metastasis are still controversy and debatable. This study investigated, by multivariate logistic regression analysis, the clinical features of skip metastasis to mediastinal lymph nodes (N(2)) in non-small cell lung cancer (NSCLC) patients.

METHODS

We collected the clinicopathological data of 256 pN(2)-NSCLC patients who underwent lobectomy plus systemic lymph node dissection in Fujian Medical University Union Hospital. The cases in the present study were divided into two groups: skip metastasis (N(2) skip+) and non- skip metastasis (N(2) skip-). A retrospective analysis of clinical pathological features of two groups was performed. To determine an independent factor, multivariate logistic regression analysis was used to identify possible risk factors.

RESULTS

A total of 256 pN(2)-NSCLC patients were recruited. The analysis results showed that gender, pathologic types, surgery, pleural involvement, smoking history, age, tumor stages, and differentiation were not statistical significant factors impacting on skip metastasis in pN(2)-NSCLC (P>0.05), whereas tumor size was an independent factor for skip metastasis (P=0.02).

CONCLUSIONS

The rate of skip lymphatic metastasis increases in pN(2)-NSCLC patients, in accompany with an increased tumor size.

Detection of pleural lymph flow using indocyanine green fluorescence imaging in non-small cell lung cancer surgery: a preliminary study

PURPOSE

Lymphatic spread of lung carcinoma to the mediastinum is a key determinant of prognosis. The lymph flow often carries metastases from the pulmonary segment directly into the mediastinal lymph nodes, without passing through the hilar nodes. This phenomenon is termed as "skip metastasis." This study investigated the subpleural lymphatic flow to the mediastinum using indocyanine green (ICG) with a near-infrared fluorescence imaging system.

METHODS

Seventeen patients with lung cancer were enrolled in this study. A 0.3 ml sample of solution containing the fluorescent dye ICG (5 mg/ml) was injected into subpleural sites near the primary tumor. Fluorescence imaging was used to monitor the flow of ICG-containing lymph from the injection site for 5 min. The relationship between the anatomical segment of the primary tumor and the lymphatic flow was assessed.

RESULTS

The lymphatic vessels draining from the injection site were revealed by the bright ICG fluorescence in 14 of the patients (82.4 %). A direct lymphatic flow to the mediastinum was confirmed in 3 of those 14 (21.4 %).

CONCLUSIONS

These findings confirm the direct flow of lymph to the mediastinum without passage through the hilum pulmonis intraoperatively. These preliminary results may provide a valuable clue for further investigations of the mechanisms underlying skip metastasis.

Pulmonary lymphatic drainage to the mediastinum based on computed tomographic observations of the primary complex of pulmonary histoplasmosis

BACKGROUND

In the primary infection of pulmonary histoplasmosis, pulmonary lesions are commonly solitary and associated with hilar and/or mediastinal nodal diseases, which spontaneously resolve, resulting in calcifications in individuals with normal cellular immunity.

PURPOSE

To assess the lymphatic drainage to the mediastinum from each pulmonary segment and lobe using computed tomographic (CT) observations of a calcified primary complex pulmonary histoplasmosis and predict which patients with N2 disease that would benefit from surgery.

MATERIAL AND METHODS

We collected 585 CT studies of patients with primary complex histoplasmosis consisting of solitary calcified pulmonary lesions and calcified hilar and/or mediastinal nodal disease. Using the N stage criteria of non-small cell lung cancer, we assessed the distribution of the involved hilar and mediastinal nodes depending on the pulmonary segment of the lesion, with a focus on skip involvement. We also assessed the correlation between the incidence of N1 and skip N2 involvement and the mean number of involved mediastinal nodal stations in the non-skip N2 and skip N2 groups.

RESULTS

Skip involvement was common in the apical segment (9/45, 20.0%), posterior segment (7/31, 22.6%), and mediolbasal segment (13/20, 65.0%) in the right lung, and in the apicoposterior segment (7/55, 12.7%), lateral basal segment (6/26, 23.1%), and posterobasal segment (16/47, 34.0%) in the left lung. The incidence of skip involvement in each segment showed a significant inverse correlation with that of N1 involvement (r = -0.51, P <0.05) in both lungs. The mean number of involved mediastinal nodal stations in the non-skip N2 and skip N2 groups in all segments of both lungs were 1.4 (434/301) and 1.2 (93/77), and the former was significantly greater than the latter (P <0.01).

CONCLUSION

Our data showed a predictable pattern of segmental and lobar lymphatic drainage to the mediastinum and suggested that skip involvement could represent the initial mediastinal node involvement via direct lymphatic drainage.

Impact of nodal status and tumor burden in sentinel lymph nodes on the clinical outcomes of cancer patients

The validation of sentinel lymph node (SLN) concept in melanoma and breast cancer has established a new paradigm in cancer metastasis that, in general, cancer cells spread in a orderly fashion from the primary site to the SLNs in the regional nodal basin and then to the distant sites. In this review article, we examine the development of SLN concept in penile carcinoma, melanoma and breast carcinoma and its application to other solid cancers with emphasis of the relationship between micrometastasis in SLNs and clinical outcomes.

Contralateral cervicomediastinal lymph node metastases from clinically occult adenocarcinoma of the lung

A 69-year-old woman with a right cervical lymphadenopathy presented with an adenocarcinoma on excisional biopsy. Computed tomography (CT) scans and a positron emission tomography scan demonstrated that the tumor was localized in the right paratracheal and cervical region. A clinical diagnosis of lung cancer arising from an unknown primary site was made based on the radiologic and immunohistochemical findings. Serial CT scans showed a growing nodule in the left apex from pinpoint size to 1 cm in diameter after several months, which was defined as the primary site at autopsy. The finding of a clinically occult lung cancer directly spreading to the contralateral mediastinal and cervical nodes by skipping ipsilateral hilar and mediastinal nodes is rare.

The problem of direct lymph drainage of the bronchopulmonary segments into the mediastinal and hilar lymph nodes

The phenomenon of skip metastases depends on the occurrence of direct metastases of non-small cell lung cancer into mediastinal lymph nodes without the involvement of hilar lymph nodes. The medical literature suggests that this prevalence ranges between 13 and 37.8% of cases. The goal of our study was to evaluate the prevalence of subpleural superficial lymphatic vessels carrying the lymph from the bronchopulmonary segments directly to the mediastinal nodes thus skipping the hilar nodes and determine whether there is a tendency towards differentiation in lymph drainage between males and females. During autopsy, 27 left and 27 right lungs were removed from 19 male and eight female cadavers. The lymphatic vessels were visualized at the mediastinal and interlobar surface of the lung by visual inspection. These vessels were then cannulated and injected with drawing ink. The first lymph node to become ink-colored via injection was dissected and histologically examined. The lymph flowed into hilar lymph nodes in 79.5% of the cases and into the mediastinal nodes in 20.5% of all the 83 vessels injected; of these 13.2% were from the right lung and in 7.2% from the left lung. The upper right lobe (5/14 vessels) and its anterior segment (3/14 vessels) were the most common source of the direct lymph drainage to the mediastinum. Vessels of 15.4% in female cadavers (4/26) and 22.8% vessels in male cadavers (13/57) traveled directly to mediastinal nodes skipping the hilar nodes. This difference was not statistically significant.

The significance of one-station N2 disease in the prognosis of patients with nonsmall-cell lung cancer

BACKGROUND

A retrospective study was conducted to define the characteristics and the prognosis of N2 disease subgroups according to their patterns of spread.

METHODS

From January 1993 to December 2004, 1,329 patients underwent lung resection for bronchogenic carcinoma The records of all patients with positive mediastinal lymph nodes at the surgical specimen (pIIIA/N2) after radical resection were analyzed, and the pattern of mediastinal lymphatic spread was classified according to regional spread, to skip metastasis, and to one or two or more lymph node stations, in relation to primary tumor location. Age, sex, type of resection, right or left lesion, T status, primary tumor location, tumor size, tumor central or peripheral location, histology, and survival were recorded and analyzed. Survival was analyzed according to regional spread or not, number of mediastinal lymph node stations involved, and skip metastasis status.

RESULTS

Among 302 cases (22.7%) with positive mediastinal lymph nodes pIIIA/N2, 66 (22%) were skip metastases, 72 (24%) had a nonregional mode of spread, and 199 (66%) included two or more stations of mediastinal lymph node invasion. Cox regression analysis of all cases disclosed malignant invasion in only one mediastinal lymph node station as the only favorable factor of survival (p < 0.001, odds ratio 0.57, 95% confidence interval: 0.42 to 0.78).

CONCLUSIONS

The presence of one-station mediastinal lymph node metastasis in patients with nonsmall-cell lung cancer who underwent major lung resection with complete mediastinal lymph node dissection proved to be a good prognostic factor that should be taken into account in the future.

Skip mediastinal nodal metastases in the IIIa/N2 non-small cell lung cancer

INTRODUCTION

To study the incidence and characteristics of mediastinal nodal metastases without N1 nodal metastases (skip N2 metastases) in patients with resected pIII/A/N2 non-small cell lung cancer.

METHODS

A total of 323 non-small cell lung cancer patients who underwent radical surgical resection with a systematic mediastinal nodal dissection in 4-year period (2000-2003) were retrospectively reviewed. The 85 patients (26%) at stage IIIA/N2 (pN2+) were grouped according to their skip metastases status. Patient data were statistically analyzed.

RESULTS

Skip N2 metastases were found in 21 patients (25%) without N1 nodal involvement. The postoperative survival for skip N2 disease was almost the same as that for pN2 disease with N1 nodal involvement. The incidence of N2 metastases seemed to be more frequent in adenocarcinoma patients (p < 0.005), but skip N2 metastases were significantly higher (p < 0.001) in squamous cell carcinoma patients. Although skip metastases involved more often upper mediastinal lymph nodes and one station level, the difference was not found statistically significant (p < 0.227). Complication rate showed no difference between analyzed groups of patients.

CONCLUSIONS

Sample mediastinal lymphadenectomy may not be appropriate in surgery for non-small cell lung cancer because skip metastases were found in 25% of patients without N1 nodal involvement.

Subpleural injection of tracer improves detection of mediastinal sentinel lymph nodes in non-small cell lung cancer

BACKGROUND

The advantages and disadvantages of various tracer injection protocols for sentinel lymph node (SLN) mapping have been extensively discussed in relation to breast and gastric cancer. But no such discussion has taken place in relation to SLN mapping in non-small cell lung cancer. We therefore studied the effect of two tracer injection protocols on SLN mapping in patients with non-small cell lung cancer; of particular interest was the relationship between subpleural tracer injection and identification of mediastinal SLNs.

METHODS

A quadrant injection group (n=49) received 1.6 ml of ferucarbotran by peritumoral quadrant injection after thoracotomy. In the subpleural injection group, the same amount of ferucarbotran was injected into the peritumoral quadrants plus the subpleural region (n=27). SLNs were then detected intraoperatively by measuring the magnetic force within lymph nodes using a hand-held magnetometer. After completing the SLN mapping, lobectomy and hilar and mediastinal lymph node dissection was performed.

RESULTS

The incidence of mediastinal SLNs was significantly higher in the subpleural injection group (45.4%) than in the quadrant injection group (14.6%) (p=0.007). Moreover, nominal logistic regression analysis revealed subpleural injection to be a significant independent factor contributing to detection of mediastinal SLNs (p=0.024, odds ratio 5.26). In the quadrant injection group, mediastinal lymph node metastasis was detected in two patients thought to have nonmetastatic parenchymal SLNs. By contrast, there were no false-negative cases in the subpleural injection group.

CONCLUSION

Subpleural tracer injection significantly improves detection of mediastinal SLNs in non-small cell lung cancer.

Surgical assessment and intraoperative management of mediastinal lymph nodes in non-small cell lung cancer

Mediastinal lymph node status has important prognostic and therapeutic implications for nonsmall cell lung cancer patients. Consequently, an accurate pathologic assessment of mediastinal lymph nodes for metastasis is essential. Despite the significance of nodal assessment, practice patterns among surgeons vary widely. Therefore we reviewed the literature to provide evidence-based recommendations regarding the ideal means and extent of preoperative and intraoperative pathologic mediastinal lymph node staging in non-small cell lung cancer patients. We found that the most sensitive and accurate intraoperative method is a complete mediastinal lymph node dissection. Pathologic evaluation of at least 10 mediastinal lymph node from at least three stations should be performed at the time of surgery.

The IASLC Lung Cancer Staging Project: Proposals for the Revision of the N Descriptors in the Forthcoming Seventh Edition of the TNM Classification for Lung Cancer

INTRODUCTION

Accurate staging of lymph node involvement is a critical aspect of the initial management of nonmetastatic non-small cell lung cancer (NSCLC). We sought to determine whether the current N descriptors should be maintained or revised for the next edition of the international lung cancer staging system.

METHODS

A retrospective international lung cancer database was developed and analyzed. Anatomical location of lymph node involvement was defined by the Naruke (for Japanese data) and American Thoracic Society (for non-Japanese data) nodal maps. Survival was calculated by the Kaplan-Meier method, and prognostic groups were assessed by Cox regression analysis.

RESULTS

Current N0 to N3 descriptors defined distinct prognostic groups for both clinical and pathologic staging. Exploratory analyses indicated that lymph node stations could be grouped together into six "zones": peripheral or hilar for N1, and upper or lower mediastinal, aortopulmonary, and subcarinal for N2 nodes. Among patients undergoing resection without induction therapy, there were three distinct prognostic groups: single-zone N1, multiple-zone N1 or single N2, and multiple-zone N2 disease. Nevertheless, there were insufficient data to determine whether the N descriptors should be subdivided (e.g., N1a, N1b, N2a, N2b).

CONCLUSIONS

Current N descriptors should be maintained in the NSCLC staging system. Prospective studies are needed to validate amalgamating lymph node stations into zones and subdividing N descriptors.

The Future in Diagnosis and Staging of Lung Cancer

Surgical techniques remain central to the diagnosis and staging of lung cancer. Clinical situations which invoke the role of surgery include the diagnosis of solitary pulmonary masses, staging of the mediastinum, restaging of the mediastinum and the assessment of resectability. The techniques available include cervical mediastinoscopy, anterior mediastinotomy, video-assisted thoracoscopy and different procedures for intra-operative mediastinal lymph node assessment including systematic nodal dissection, lobe-specific nodal dissection and sentinel node mapping. The staging of lung cancer is continuously evolving as technological advances combine with clinical advances to better stratify patients into treatment and prognostic categories and alter pre-operative investigation algorithms. Although most of the surgical techniques have been around for many years, it is their application in future which is likely to change. The increasing use of positron emission tomography/computed tomography fusion imaging is raising the proportion of patients being shown to have additional lesions that could contraindicate surgical treatment but which require tissue confirmation to exclude a false-positive examination. Many such lesions are amenable to the expanding techniques available to the interventional endoscopist. The relationship between the surgeon and the endoscopist must become closer to ensure that the appropriate technique is used at each point in the patient's pathway. The future of surgical techniques will be driven by: (1) developments in screening and imaging, with a likelihood that more early stage cancers will present and may be amenable to minimally invasive surgical approaches with the possibility of a role for robotics and nanotechnology; (2) improvements in neoadjuvant therapies which will demand flawless mediastinal staging and restaging; (3) advances in molecular biology which, whilst currently requiring that surgery provide samples of tumour and lymph node tissue to fully characterize the disease, do hold the promise that ever smaller amounts of tissue will be required and that eventually the genetic fingerprint will provide a biological ultrastaging to perhaps supersede anatomical staging.

Analysis of risk factors for skip lymphatic metastasis and their prognostic value in operated N2 non-small-cell lung carcinoma

BACKGROUND

The aim of this study is to report a series and to analyze risk factors for skip lymphatic metastasis an their prognostic value in operated N2 non-small-cell lung carcinoma.

METHODS

From 1997 to 2002, 142 patients classified pN2 were included in the study. Tumours were classified according to the TNM classification. Skips metastases were defined by the cases of N2 disease without lobar and interlobar and hilar lymph node involvement. A skip (+) and a skip (-) group were defined. Characteristics of tumours, ganglionar involvement and survival were analysed in both groups.

RESULTS

Forty-two patients fulfilled the criteria for skip metastasis. The average number of mediastinal lymph nodes resected by patient was similar in both groups, whereas more intrapulmonary nodes were dissected in the skip (-) group (4.7 +/- 3 vs 3 +/- 3; p < 0.002). The ratio of involved to resected lymph nodes was 0.47 +/- 0.27 in the skip (-) group vs 0.23 +/- 0.20 in the skip (+) group (p < 0.0001). In the skip (+) group, 85% of the patients presenting with a right upper lobe tumour had involvement of the superior mediastinal lymph nodes against 40% in the skip (-) group. The 5-year survival rate was 48% in the skip (-) group vs 37% in the skip (+) group (p = 0.49). In multivariate analysis, incomplete resection, tumour size, extended resection and pT were significant prognostic factors.

CONCLUSIONS

Skip metastasis are frequent in non-small-cell lung cancer and complete dissection of hilar and mediastinal lymph nodes should remain the surgical standard procedure for this disease. However, skip metastasis are not an independent prognostic factor in survival.

Results of Initial Operations in Non–Small Cell Lung Cancer Patients With Single-Level N2 Disease

BACKGROUND

There is still debate regarding the use of surgery in the management of non-small cell lung cancer patients with N2 disease. The primary aim of the present study was analysis of the results of initial operations in non-small cell lung cancer patients with single-level N2 disease.

METHODS

Ninety-four patients with the disease who underwent initial surgery consisting of complete resection of the primary site plus systematic lymphadenectomy were examined. We also immunohistochemically examined lymphatic vessel density and vascular endothelial growth factor-C expression.

RESULTS

The overall 5- and 10-year survival rates for the 94 patients were 27.1% and 12.1%, respectively, with a median survival of 22 months. When stratified by skipping status, the 5-year survival rates for the patients in skip-N2 and non-skip-N2 groups were 33.4% and 19.8%, respectively (p = 0.0189). Skip metastasis, T factor, subcarinal lymph node metastasis, and adjuvant chemotherapy were recognized as independent prognostic indicators. In both skip-N2 and non-skip-N2 groups, distant relapse was the dominant pattern of recurrence. Although the peritumoral lymphatic vessel density was associated with vascular endothelial growth factor-C expression in tumors, the lymphangiogenic profile appeared to be different between skip-N2 and non-skip-N2 tumors, suggesting different nodal metastatic process.

CONCLUSIONS

Lung cancer patients with single-level N2 disease are an oncologically heterogeneous cohort. Although further studies involving randomized comparisons are required, the poor outcomes found here indicate that the initial operation has yet to be validated for patients with this disease.

Impact of skip metastasis in gastric cancer

BACKGROUND

Several studies have shown the features of skip metastasis in other cancers besides gastric cancer. Since minimally invasive surgery has been applied to gastric cancer, the concerns and awareness of skip metastasis have grown in the medical community. We conducted the present retrospective study to reveal the clinicopathological characteristics of patients with skip metastasis. We also wished to clarify the clinical impact of skip metastasis for gastric cancer.

METHODS

Five hundred and eighty-nine patients having lymphatic metastases were enrolled in the present study. Among them, 266 patients had positive nodes extending into the N2 group. We divided these patients into the skip positive (+) and the skip negative (-) group, and we comparatively analysed clinicopathological factors and calculated the survival probabilities for the two groups.

RESULTS

The skip (+) and skip (-) groups involved 14 (5.3%) and 252 (94.7%) patients, respectively. Of all the investigated factors, a significant difference between two groups was observed only in the total number of retrieved nodes. Stations of skip nodes were along left gastric (7), anterior common hepatic (8a), celiac (9), splenic (11) artery and right paracardial nodes (1). The survival curves calculated in the present study did not show any statistical differences between the groups.

CONCLUSIONS

Due to problems of skip metastasis in gastric cancer, D2 lymph node dissection should be performed until sentinel node detection is feasible and reliable. The potential risk from skip metastasis is not great and skip metastasis itself should not be a major consideration in therapeutic decisions.

Complete resection via medial sternotomy for non-small cell lung cancer in the right upper lobe

BACKGROUND

Right upper lobectomy with right cervical and bilateral mediastinal lymph node dissection via a median approach was performed for non-small cell lung cancer.

METHODS

From 1995 to 2003, 48 patients aged < or = 70 years underwent resection of cancer in the right upper lobe, including 26 with N0, four with N1 and 18 with N2 disease.

RESULTS

Metastases to the right cervical, highest mediastinal, pretracheal and bilateral tracheobronchial lymph nodes were frequent. There were no operative or hospital deaths. Preoperative accuracy of N-factor diagnosis was only 35.4%. The overall 5-year survival rate was 58.8%. The rate for C-N2 disease (n = 18) was 42.6%, and the rate for p-N2 disease (n = 7) and p-N3 disease (n = 13) was 57.1% and 0%, respectively, using the Kaplan-Meier method.

CONCLUSIONS

Patients without N3 disease have a good prognosis, and extended and systematic radical lymphadenectomy via median sternotomy improves the staging, and possibly the prognosis of pure N2 disease.

Sentinel lymph node mapping and molecular staging in nonsmall cell lung carcinoma

BACKGROUND

Lymph node (LN) involvement predicts recurrence in patients who have undergone resection of apparently localized nonsmall cell lung carcinoma (NSCLC). Standard detection methods for LN disease have a low sensitivity, and many patients with apparent N0 disease status develop recurrent disease. Molecular techniques can improve the detection of micrometastases, whereas sentinel lymph node (SLN) mapping can indicate which LN may contain micrometastases. These methods, although potentially complementary, have not, to the authors' knowledge, been used together previously.

METHODS

The authors used SLN mapping and molecular staging to improve the detection of LN micrometastases in patients with NSCLC. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis for cytokeratin-7 (CK7), expressed both in normal lung and in malignant lung, was used to identify tumor-derived material in LN.

RESULTS

SLN mapping was performed in 13 patients, with 1-3 SLNs identified in each patient, and sufficient RNA for RT-PCR was obtained in 12 of these 13 patients. Eleven of 12 tumors expressed CK7. Overall, 32 LNs were positive for CK7, including 13 of 21 SLNs. Ten of 11 patients with evaluable SLNs had at least 1 CK7-positive SLN. Routine pathology showed Stage I disease in eight patients, T3N0 disease in one patient, and LN-positive disease in two patients. Of the nine patients with N0 disease according to routine pathology that was evaluable by RT-PCR, eight patients were upstaged by this technique. All patients with positive LN status by routine pathology who were evaluable by RT-PCR analysis had positive RT-PCR results.

CONCLUSIONS

LN micrometastases were common in resected NSCLC, including patients with N0 disease according to routine pathology. SLN mapping was useful for identifying disease-containing LNs. This approach may be useful for stratifying histologically N0 patients into higher risk and lower risk groups.

Intraoperative sentinel lymph node mapping of the lung using near-infrared fluorescent quantum dots

BACKGROUND

The presence of lymph node metastases is an important prognostic marker with regard to non-small-cell lung cancer (NSCLC). Assessment of the sentinel lymph node (SLN) for the presence of tumor may improve staging. Our objective was to develop an optical noninvasive imaging tool that would permit intraoperative SLN mapping and provide real-time visual feedback for image-guided localization and resection.

METHODS

Invisible near-infrared (NIR) light penetrates relatively deeply into tissue and background autofluorescence is low. We have developed a NIR fluorescence imaging system that simultaneously displays color video and NIR images of the surgical field. We recently engineered 15 nm nonradioactive NIR fluorescent quantum dots (QDs) as optimal lymphotrophic optical probes. The introduction of these QDs into lung tissue allows real-time visualization of draining lymphatic channels and nodes.

RESULTS

In 12 Yorkshire pigs (mean weight 35 kg) we demonstrated that 200 pmol of NIR QDs injected into lobar parenchyma accurately maps lymphatic drainage and the SLN. All SLNs were strongly fluorescent and easily visualized within 5 minutes of injection. In 14 separate injections QDs localized to a mediastinal node, whereas in 2 injections QDs localized to a hilar intraparenchymal node. Histologic analysis in all cases confirmed the presence of nodal tissue.

CONCLUSIONS

We report a highly sensitive rapid technique for SLN mapping of the lung. This technique permits precise real-time imaging and therefore overcomes many limitations of currently available techniques.

Skip mediastinal lymph node metastasis and lung cancer: a particular N2 subgroup with a better prognosis

BACKGROUND

Lymph node (LN) metastases from lung cancer may skip the intrapulmonary nodes directly to the mediastinum ([N1-]N2 vs [N1+]N2). This phenomenon is frequent. Patients with such a metastatic pattern appear to have a better prognosis following surgery. Our purpose was to further study the clinical significance and prognostic value of this particular group of (N1-)N2 patients.

METHODS

We retrospectively analyzed the data of 731 patients with a pN2 stage who underwent resection for non-small cell lung cancer. Patients with (N1-)N2 metastases (n = 209) were compared to patients with intrapulmonary (N1+)N2 (n = 522).

RESULTS

In the (N1-)N2 group, lobectomies were more frequent (54% vs 33%, p = 0.00), metastases more frequently involved a single LN station (79.4% vs 56.3%, p < 0.000001), and primary tumor was more often located in the upper lobes (67.4% vs 55.6%, p = 0.0066). (N1-)N2 was a factor of better prognosis (5 year survival rates 34.4% vs 18.5%, p = 0.00006), which proved also significant when only a single station was involved (38.4% vs 24%, p = 0.0005). These results were confirmed by multivariate analysis.

CONCLUSIONS

(N1-)N2 skip metastasis is a unique subgroup of pN2 disease. Lung lymph drainage anatomy may explain the occurrence of these metastases. They form an independent prognostic factor of survival suggesting the need for further study, the results of which may lead to better knowledge of lung cancer, improved classification, and adapted adjuvant therapy.

Mediastinal intraoperative radioisotope sentinel lymph node mapping in non-small-cell lung cancer

BACKGROUND

Lymph node metastases are significant prognostic factors in localized non-small-cell lung cancer (NSCLC). Nodal micrometastases may not be detected using current histological methods.

AIM

To determine the accuracy and role of sentinel lymph nodes (SLNs) in patients with NSCLC.

METHODS

Intraoperative technetium-99m (Tc) sulphur colloid SLN mapping was performed in patients with NSCLC. Serial section histology and immunohistochemistry were used to validate the SLNs and to identify the presence of micrometastatic disease. The study was carried out on 28 consecutive patients (male/female, 25/3; mean age, 57.05+/-7.1 years) with resectable NSCLC. During thoracotomy, 0.25 mCi of Tc sulphur colloid was injected into four quadrants peritumorally. Radioactivity was counted intraoperatively, a mean of 45 min (range, 30-60 min) after injection. SLN was defined as the node with the highest count rate using a hand-held gamma probe counter. Resection with mediastinal node dissection was performed and the findings were correlated with histological examination.

RESULTS

SLNs were identified in 26 of 28 patients (92.8%) with a total number of 32 SLNs. Seven of 32 (21.8%) of these SLNs were positive for metastatic involvement after histological and immunohistochemical examination. In two patients (7.1%), SLNs could not be found.

CONCLUSIONS

These results demonstrate the feasibility of this procedure in identifying the first site of potential nodal metastasis of NSCLC. This method may improve the precision of pathological staging.

Le traitement chirurgical du cancer bronchique non à petites cellules

INTRODUCTION

Surgery remains the best option for curative treatment of early stages Non-small cell lung cancer (NSCLC). In this article we review the current status and future perspectives of surgical treatment of NSCLC.

STATE OF ART

An important part of the surgical procedure is the final determination of the staging with evaluation of the resectability of the tumor and its nodal status. This requires a systematic hilar and mediastinal nodal dissection and a complete resection that remains a major prognostic factor.

PERSPECTIVES

In order to preserve pulmonary function, lobectomies with the use of broncho- or arterioplasty have been developed with reduction in the number of pneumonectomies. For peripheral T1N0 NSCLC, video-assisted (VATS) lobectomy has become technically feasible with survival, in non-randomised studies, at least as good as the survival after open resection. While VATS has a clear role in staging of lung cancer, its role in the treatment of lung cancer however remains debatable. In case of involved mediastinal nodes (N2 disease) induction therapy is given in many centers and patients with mediastinal downstaging have a significantly better survival than non-responders. Restaging of the mediastinum is at the moment far from accurate. In case of locally advanced tumour (cT4), new surgical techniques and approaches make resection of carina, vena cava superior, vertebrae feasible with acceptable morbidity and mortality but additional studies are required.

CONCLUSIONS

Surgery remains the treatment of choice for curative treatment of NSCLC. The evolution of surgical techniques and the use of multimodality treatment further improve the results of surgical management. Rigorous patient selection, meticulous surgical technique and adequate peri- and postoperative management can keep operative morbidity and morbidity acceptable.

Prolonged survival in patients with resected non-small cell lung cancer and single-level N2 disease

OBJECTIVES

To test the hypothesis that patients with non-small cell lung cancer and single-level N2 metastases constitute a favorable subgroup of patients with mediastinal metastases, we analyzed the results of the Eastern Cooperative Oncology Group 3590 (a randomized prospective trial of adjuvant therapy in patients with resected stages II and IIIa non-small cell lung cancer) by site of primary tumor and pattern of lymph node metastases.

METHODS

Accurate staging was ensured by mandating either systematic sampling or complete dissection of the ipsilateral mediastinal lymph nodes. The overall survival of patients with left lung non-small cell lung cancer and metastases in only 1 of lymph node levels 5, 6, or 7 and right lung non-small cell lung cancer with metastases in only 1 of levels 4 or 7 was compared with that of patients with N1 disease originating in the same lobe.

RESULTS

The median survival of the 172 patients with single-level N2 disease was 35 months (95% confidence interval: 27-40 months) versus 65 months (95% confidence interval: 45-84 months) for the 150 patients with N1 disease (median follow-up 84 months, P =.01). However, among patients with left upper lobe tumors, survival was not significantly different between patients with N1 disease and patients with single-level N2 disease (49 vs 51 months, P =.63). The median survival of the 71 patients with single-level N2 metastases without concomitant N1 disease (skip metastases) was 59 months (95% confidence interval: 36-107 months) versus 26 months (95% confidence interval: 16-36 months) for the 145 patients with both N1 and N2 metastases (P =.001).

CONCLUSIONS

Survival of patients with left upper lobe non-small cell lung cancer and metastases to single-level N2 lymph nodes is not significantly different from that of patients with N1 disease. The presence of isolate N2 skip metastases is associated with improved survival when compared with patients with both N1 and N2 disease. Survival should be reported by the lobe of primary tumor and metastatic pattern to guide future clinical trial development, treatment strategies, and revisions of the TNM staging system.

Involvement of lymphatic metastatic spread in non-small cell lung cancer accordingly to the primary cancer location

OBJECTIVES

The purpose of the study is to investigate the contribution of lymphatic spread in operable non-small cell lung cancer (NSCLC) in relation to the cancer location.

METHODS

We retrospectively studied 557 consecutive patients [514 males and 43 females, mean age 62.5 +/- 9.1 years (range, 20-84)] who underwent a major lung resection due to NSCLC in our department, from January 1995 to December 1999. Preoperative staging for metastatic disease was negative. Extended mediastinal lymph node dissection was performed in all lung resections.

RESULTS

The pathology report revealed 220 adenocarcinomas, 276 squamous-cell, 34 undifferentiated, 25 adenosquamous and 2 large-cell carcinomas. The TNM stage was IA in 52 patients, IB in 109, IIA in 20, IIB in 146, IIIA in 190, IIIB in 35 and IV in 5. The classification of disease was N0 in 240 (40.1%) patients, N1 in 179 (32.1%) and N2 in 138 (24.8%). Twenty-eight patients (5.03%) presented a skip metastasis to hilar lymph nodes, while 27 patients (4.85%) presented with skip metastasis to the mediastinum. The size of the primary tumors presenting with metastases was significantly smaller in adenocarcinomas compared to squamous-cell carcinomas (P = 0.046). Regarding the right lung, tumors originating in the upper lobe mainly metastasized to level No. 4, while tumors of the middle lobe spread to stations Nos. 4 and 7, and those in the lower lobe to level No. 7. Regarding the left lung, tumors originating in the upper lobe metastasized to level No. 5, while tumors within the lower lobe spread to stations, Nos. 7-9.

CONCLUSIONS

Mediastinal lymph nodal dissection is necessary for the accurate determination of pTNM stage. It seems that there is no definite way for lymphatic spreading in relation to the location of the cancer. Skip metastasis to the mediastinal lymph nodes was present in 4.85% of our patients, while adenocarcinomas, even small-sized ones, are more aggressive than squamous-cell carcinomas.

Skip metastasis in nonsmall cell lung carcinoma

BACKGROUND

Skip metastasis to mediastinal lymph nodes is a prognostic factor for patients with nonsmall cell lung carcinoma (NSCLC). Little is known about the biologic behavior of tumors with noncontinuous spread to the mediastinal lymph nodes. In patients with pN2 skip metastases, micrometastases to N1 lymph nodes, which only mimic skip metastases, have not been investigated.

METHODS

In a retrospective study, the authors analyzed the primary tumor specimens from 45 patients with pN2 NSCLC (18 patients had squamous cell carcinomas, 23 had adenocarcinomas, and 4 had large cell carcinomas). They immunohistochemically evaluated the expression of p21, p53, MUC-1, Bcl-2, c-ErbB-2, and E-cadherin. Survival rates and biomarker expression levels were compared between patients with pN2 disease and infiltration of N1 lymph nodes (without skip metastasis [n = 28]) and patients with pN2 disease without N1 infiltration (with skip metastasis [n = 17]). To evaluate micrometastasis in the pN1 lymph nodes of 17 patients with skip metastases, lymph nodes were stained using the anticytokeratin antibody, AE1/AE3.

RESULTS

The 5-year survival rate of patients with skip metastases was 41%, compared with 14% for patients without skip metastases (P = 0.019). In a multivariate analysis, the incidence of skip metastases did not vary significantly according to gender, age, histology, pT status, or cM status. Three skip-positive patients (17.6%) had micrometastatic tumor involvement of pN1 lymph nodes. After adding these patients to the group of patients without skip metastases, there was still a significant difference in survival between the two groups. p53, MUC-1, c-ErbB-2, and E-cadherin expression levels in primary tumor specimens were not significantly different in patients with continuous metastasis and patients with skip metastases. Patients with skip metastases expressed lower levels of p21 (P = 0.026), whereas Bcl-2 expression levels were considerably higher (P = 0.019) compared with the corresponding levels in patients without skip metastases.

CONCLUSIONS

Patients with NSCLC and pN2 skip metastases have a more favorable prognosis than do patients with pN2 disease without skip metastases. Tumor specimens from these patients exhibit elevated expression of the antiapoptosis gene BCL2 and lower expression levels of p21 relative to patients with pN2 disease without skip metastases. Micrometastases occurred in 3 of 17 (17.6%) patients with pN2 disease and skip metastases diagnosed by routine histopathology.

Lung cancer staging

The staging of lung cancer is a continuously progressing field, with advances in technology not only improving prognostic accuracy, but fundamentally changing pre-operative investigation algorithms. Noninvasive staging is currently undergoing revolutionary developments with the advent of Positron Emission Tomography, whereas Video-Assisted Thoracic Surgery has already been established as an essential, minimally invasive diagnostic tool for invasive histological staging. Molecular staging may transform future lung cancer staging, promising extremely accurate substaging, and potentially prompting a revision of our anatomically based conceptualization of lung cancer spread. This review presents an appraisal of current lung cancer staging modalities, and presents an overview of recent developments in molecular staging.

Heterogeneity of stage IIIA non-small cell lung cancers (NSCLC) and evaluation of late results of surgical treatment

AIMS

The aim of the study was assessment of the heterogeneity of stage IIIA non-small cell lung cancers (NSCLC) and the late results of surgical treatment.

METHODS

The study group consisted of 83 consecutive patients discharged between 1988 and 1992 undergoing radical operative treatment for stage IIIA NSCLC. Squamous cell carcinoma was diagnosed in 54 (65.1%) patients, adenocarcinoma in 23 (27.7%), large cell carcinoma in 2 (2.4%) and mixed (i.e. adenoid-squamous type) in 4 (4.8%). In respect of pTNM staging, 19 (22.9%) patients had T3N1M0, 35 (42.2%) had T2N2M0 and 29 (34.9%) had T3N2M0.

RESULTS

Overall, 13.3% of patients with stage IIIA NSCLC survived 5 years following the operation and 8.7% survived 10 years. Analysis of follow-up study indicated that this group was heterogenic. In T3N1M0 group 26.3% survived 5 years following the operation, in T2N2M0 group 14.3%, in T3N2M0 group 3.5% (P = 0.015). Of 23 patients with N2 disease and no metastases in hilar lymph nodes ('skip' metastases), 26.1% survived 5 years, whereas none of 41 patients with metastases spreading by continuity survived (P = 0.0015). If mediastinal lymph node metastases were diagnosed in one level, 25% patients survived 5 years, but if two or more levels were affected, 2.3% only (P = 0.0214): 85.7% of patients with well-differentiated (G1) cancer survived 5 years and 62.0% 10 years, whereas among those with moderately differentiated (G2) tumours, 11.8% and 8.8%, respectively. No patient survived 5 years after resection of poorly differentiated (G3) cancer (P < 0.001).

CONCLUSIONS

(1) Patients operated for stage IIIA NSCLC are a heterogeneous group, which makes it difficult to predict late results. (2) Patients operated for stage IIIA NSCLC have a better prognosis if metastases are discovered in level one mediastinal lymph nodes, particularly in the superior part of mediastinum, or if 'skip' metastases (pulmonary hilus unaffected) are discovered, as compared to those with N2 disease. (3) Poor histologic differentiation of the tumour is a bad prognostic factor.