Assessing the prognostic value of the extent of mediastinal lymph node infiltration in surgically-treated non-small cell lung cancer (NSCLC)

Feasibility of nodal classification for non-small cell lung cancer by merging current N categories with the number of involved lymph node stations

Introduction

The aim of this study was to assess the prognoses of patients with non‐small cell lung cancer (NSCLC) according to the current nodal (N) categories of the tumor, node and metastasis (TNM) classification and the number of involved lymph node stations.

Methods

Five hundred and seventy patients with NSCLC underwent surgery from 1 January 2005 to 31 December 2009 and were analysed retrospectively. Postoperative overall survival was analysed according to two nodal classifications: the current N0, N1, N2 and N3 categories and those based on the number of involved nodal stations: N0, N1a (single N1), N1b (multiple N1), N2a1 (single N2 without N1), N2a2 (single N2 with N1), N2b1 (multiple N2 without N1) and N2b2 (multiple N2 with N1).

Results

Five‐year survival rates were 76.1%, 53.4% and 26.3% for N0, N1 and N2, respectively (P < 0.001). When survival was analysed by the number of involved nodal stations, the groups with significant differences were maintained; otherwise, they were merged, and new codes were assigned as follows for exploratory analyses: NA (N0), NB (N1a), NC (N1b, N2a (i.e., N2a1 and N2a2) and N2b1) and ND (N2b2). Five‐year survival rates were 76.1%, 60.0%, 39.1%, and 11.4% for NA, NB, NC and ND, respectively, and there were significant differences among them. This N classification was an independent prognostic factor in multivariate analyses.

Conclusion

Pending prospective and international validation, it is practical to merge the current N categories with the number of involved lymph node stations when evaluating the postoperative prognosis of NSCLC patients.

Lymph node dissection after pulmonary resection for lung cancer: a mini review

An accurate staging of a malignant disease is imperative in order to plan pre- and post-operative therapy, define prognosis and compare studies. According to the European Society of Thoracic Surgeons (ESTS) guidelines a systematic lymph node (LN) dissection is recommended in all cases of pulmonary resection for non-small cell lung cancer (NSCLC). The current lung cancer staging system considers the lymphatic stations involved but not the number of LNs. Up to date, published scientific studies on hilar and mediastinal lymphadenectomy mainly have been regarded the type of LN dissection procedure after pulmonary resection (selected LN biopsy, LN sampling, systematic nodal dissection, lobe specific nodal dissection and extended LN dissection) focusing particularly on the comparison between mediastinal LN dissection (MLND) and mediastinal LN sampling (MLNS). Recently, further investigations have been concentrated on surgical approach (videothoracoscopic vs. thoracotomic approach) used to perform pulmonary resection and following LN dissection in order to achieve a complete mediastinal lymphadenectomy. This short synthesis aims to present the current experiences in this setting.

A standardized technique of systematic mediastinal lymph node dissection by video-assisted thoracoscopic surgery (VATS) leads to a high rate of nodal upstaging in early-stage non-small cell lung cancer

BACKGROUND

A substantial part of the oncologic surgical procedure in non-small cell lung cancer (NSCLC) is systematic lymph node dissection (sLND). However, controversies still exist regarding the quality of minimally invasive (video-assisted thoracoscopic surgery, VATS) sLND in oncologic resections. The rate of stage migration from clinical to pathological N-status has been discussed as one parameter for the quality of sLND.

METHODS

Between March 2011 and May 2014, seventy-seven patients (62 male, 15 female) were scheduled for anatomical lung resection and sLND by VATS for clinical stage I (UICC 7th edition) NSCLC. Preoperative staging was performed by [18F]-fluorodesoxyglucose positron emission tomography with computed tomography (FDG-PET/CT). Patient data were retrospectively analyzed with regard to divergence in clinical and pathological N-factor. FDG-PET/CTs of patients with lymph node (LN) upstaging after VATS resections were blindly re-evaluated by an experienced radiologist.

RESULTS

In FDG-PET/CT, preoperative tumor stage was cT1N0M0 in 41 (53.2%) and cT2aN0M0 in 28 (36.4%) patients. In six (7.8%) patients the primary tumor was not suspicious for malignancy, and in two (2.6%) patients the tumor was not evaluable due to prior wedge resection before FDG-PET/CT. Thirty-one (40.3%) left-sided and 46 (59.7%) right-sided pulmonary resections with sLND were performed; 19.57 ± 0.99 LNs were dissected. In 13 (16.9%) patients a nodal stage migration from preoperative clinical to postoperative pathological N-stage was observed [cN0 to pN1 in 9 (11.7%) and cN0 to pN2 in 4 (5.2%) cases]. In correlation to the clinical T-factor, the rate of N-factor upstaging for cT1 was 12.2% and for cT2a was 28.6%, respectively. In 50% of the patients with postoperative nodal staging shift, no changes were observed on re-evaluation of the preoperative FDG-PET/CT.

CONCLUSION

In this series of clinical stage I NSCLC patients, the rate of nodal stage migration after sLND by VATS is higher than previously reported. Prospective randomized controlled trials are needed to prove the oncologic quality of a sLND by VATS versus standard open approach.

Identification of biological properties of intralymphatic tumor related to the development of lymph node metastasis in lung adenocarcinoma

Background

Intralymphatic tumors in the extratumoral area are considered to represent the preceding phase of lymph node metastasis. The aim of this study was to clarify the biological properties of intralymphatic tumors susceptible to the development of lymph node metastasis, with special reference to the expression of cancer initiating/stem cell (CIC/CSC) related markers in cancer cells and the number of infiltrating stromal cells.

Material and Methods

Primary lung adenocarcinomas with lymphatic permeation in the extratumoral area were retrospectively examined (n = 107). We examined the expression levels of CIC/CSC related markers including ALDH1, OCT4, NANOG, SOX2 and Caveolin-1 in the intralymphatic cancer cells to evaluate their relationship to lymph node metastasis. Moreover, the number of infiltrating stromal cells expressing CD34, α-smooth muscle actin, and CD204 were also evaluated.

Results

Among the intralymphatic tissues, low ALDH1 expression in cancer cells, high SOX2 expression in cancer cells, and a high number of CD204(+) macrophages were independent predictive factors for lymph node metastasis (P = 0.004, P = 0.008, and P = 0.028, respectively). Among these factors, only low ALDH1 expression in cancer cells was significantly correlated with the farther spreading of lymph node metastasis (mediastinal lymph node, pathological N2) (P = 0.046) and the metastatic lymph node ratio (metastatic/resected) (P = 0.028). On the other hand, in the primary tumors, ALDH1 expression in the cancer cells was not associated with lymph node metastasis. Intralymphatic cancer cells expressing low ALDH1 levels exhibited lower E-cadherin expression levels than cancer cells with high levels of ALDH1 expression (P = 0.015).

Conclusions

Intralymphatic cancer cells expressing low levels of ALDH1 and infiltrating macrophages expressing CD204 have a critical impact on lymph node metastasis. Our study also highlighted the significance of evaluating the biological properties of intralymphatic tumors for tumor metastasis.

Detection of human telomerase reverse transcriptase mRNA in cells obtained by lavage of the pleura is not associated with worse outcome in patients with stage I/II non-small cell lung cancer: results from Cancer and Leukemia Group B 159902

OBJECTIVE

Previous studies suggest that cytologic analysis of cells obtained by lavage of the pleural surfaces at the time of resection of non-small cell lung cancer can identify patients at risk for recurrence. Because telomerase gene expression has been associated with worse outcome in non-small cell lung cancer, we hypothesized that identification of cells obtained from pleural lavage that express telomerase would identify patients at risk for recurrent disease.

METHODS

Patients with presumed non-small cell lung cancer underwent thoracotomy with curative intent. Cells obtained by lavage of the pleural surfaces were analyzed for telomerase catalytic subunit human telomerase reverse transcriptase mRNA expression using reverse transcriptase polymerase chain reaction.

RESULTS

A total of 194 patients with stage I/II non-small cell lung cancer had adequate samples, and median follow-up was 60 months (17-91 months). By using Cox models, no statistical differences were found between human telomerase reverse transcriptase-negative and positive patients in disease-free survival (hazard ratio, 1.28; 95% confidence interval, 0.85-1.94; log-rank test, P = .2349) or overall survival (hazard ratio, 1.13; 95% confidence interval, 0.72-1.79; log-rank test, P = .5912) CONCLUSIONS: Detection of human telomerase reverse transcriptase in cells obtained from pleural lavage of patients with stage I/II non-small cell lung cancer does not identify patients at risk for recurrent disease.

Validation of the lymph node ratio as a prognostic factor in patients with N1 nonsmall cell lung cancer

BACKGROUND

The number of positive lymph nodes (LNs) has been proposed as a prognostic indicator in N1 nonsmall cell lung cancer (NSCLC). However, the number of positive LNs is confounded by the number of LNs resected during surgery. The lymph node ratio (LNR) (the ratio of the number of positive LNs divided by the number of LNs resected) can circumvent this limitation. The prognostic significance of the LNR has been demonstrated in elderly patients with NSCLC. The objective of the current study was to evaluate whether a higher LNR is a marker of worse survival in patients with NSCLC aged ≤65 years who have N1 disease.

METHODS

The Surveillance, Epidemiology, and End Results database was used to identify 4004 patients who underwent resection for N1 NSCLC. Patients were classified into 3 groups according to LNR (≤0.15, 0.16-0.5, and >0.5). Associations of the LNR with lung cancer-specific and overall mortality were evaluated using the Kaplan-Meier method. Stratified and Cox regression analyses were used to assess correlations between the LNR and survival after adjusting for other prognostic factors.

RESULTS

Unadjusted analysis indicated that a higher LNR was associated with worse lung cancer-specific survival (P < .0001) and overall survival (P < .0001). Stratified and multivariate analyses also indicated that the LNR was an independent predictor of survival after controlling for potential confounders.

CONCLUSIONS

The current results confirmed that the LNR is an independent prognostic factor for survival in patients with N1 NSCLC. This information may be used to identify patients who are at greater risk of cancer recurrence.

A novel clinical prognostic score incorporating the number of resected lymph-nodes to predict recurrence and survival in non-small-cell lung cancer

BACKGROUND

The number of resected lymph-nodes (#RNs) has proven prognostic in breast and colorectal cancer. Here we evaluated its prognostic impact in a series of resected NSCLC patients.

METHODS

A panel of established prognostic factors plus (1) #RNs or (2) the ratio between the number of metastatic nodes and #RNs (NR) were correlated to overall- (OS), cancer-specific- (CSS), and disease-free-survival (DFS), using the Cox-model. Risk-classes according to hazard ratios (HR) were generated. Internal and external validation was accomplished.

RESULTS

A dataset of 415 resected NSCLC patients was retrieved. At multivariate analysis, #RNs and NR were independent factor for longer OS, CSS and DFS (p<0.0001). Patients with a #RNs>10 (identified optimal cut-off) had a statistically significant OS (p=0.02) and DFS (p=0.0005) benefit. In node-positive patients, a NR<9% significantly correlated with better outcome. Stratification into High-, Medium-, and Low-Risk classes, based on High- (HRFs: stage, N-status, age, #RNs) and Intermediate-Risk Factors (IRFs: sex, grading, histology), efficiently predicted outcomes (p<0.0001). The risk class model performance was externally validated in and independent dataset of 297 patients.

CONCLUSIONS

These results contribute to complete the panel of prognostic factors for resected NSCLC. A prospective larger validation and comparison with molecular prognostic tools is warranted.

The impact of multiple metastatic nodal stations on survival in patients with resectable N1 and N2 nonsmall-cell lung cancer

BACKGROUND

The aim of the study was to identify common prognostic factors in nonsmall-cell lung cancer (NSCLC) with N1 and N2 nodal involvement.

METHODS

A retrospective review of NSCLC patients who underwent primary surgical resection without neoadjuvant chemotherapy was performed. In all, 280 patients were included in this study, and there were 132 patients with N1 disease (N1 group) and 148 patients with N2 disease (N2 group). The median follow-up period was 26 months, and complete follow-up was possible in 269 patients (96%).

RESULTS

Lobectomy was performed in 194 patients (69%), bilobectomy was performed in 43 (15%), and pneumonectomy was performed in 43 (15%). Complete resection was possible in 273 patients (98%), and operative death occurred in 5 patients (2%). The overall and disease-free 5-year survival rates were 63% and 55%, respectively, in the N1 group, and 44% and 32%, respectively, in the N2 group (p < 0.05). The prognostic factors for overall survival in both the N1 and N2 groups were age and the number of metastatic nodal stations; however, N2 metastasis was not a significant prognostic factor in the multivariate analysis. The poor prognosis of the patients in the N2 group was due to the greater incidence of multiple node involvement in comparison with the N1 group (73% versus 15%; p < 0.05).

CONCLUSIONS

Multiple metastatic nodal stations was the common prognostic factor in resectable NSCLC patients with nodal metastasis, and mediastinal nodal involvement was associated with a higher chance of multiple-station metastasis in this study.

Significance of extranodal extension of regional lymph nodes in surgically resected non-small cell lung cancer

STUDY OBJECTIVES

Regional lymph node (LN) involvement affects the prognosis of patients with surgically resected non-small cell lung cancer (NSCLC). The significance of extranodal extension in these groups of patients was prospectively studied to determine its clinicopathologic relationships and its influence on patient survival.

METHODS

A total of 199 NSCLC patients who were proved to have regional LN involvement after resection were included. Histologic examinations including tumor cell type, grade of differentiation, vascular invasion, regional LN metastasis emphasizing the number and station of LN involvement, the presence or absence of extranodal extension, and the immunohistochemistry of p53 expression were obtained. The relationships between extranodal extension and histologic type, grade of differentiation, vascular invasion, tumor size, pathologic stage, p53 expression, or patient survival were analyzed.

RESULTS

Extranodal extension was significantly higher in women, adenocarcinoma, advanced stage, tumors with vascular invasion, or p53 overexpression. The total number and positive rate of resected LNs with extranodal extension were significantly correlated with advanced stage, tumors with vascular invasion, or p53 overexpression. By multivariate analysis of survival, the presence or total number of LNs with extranodal extension, tumor stage, and p53 expression were significant prognostic factors. The 5-year survival rate of stage IIIA patients without extranodal extension (30.4%) was significantly better than that of stage II patients with extranodal extension (16.8%). No survival difference between extranodal positive stage II and IIIA patients was noted.

CONCLUSIONS

Extranodal extension of regional LNs is an important prognostic factor in patients with surgically resected NSCLC.

Results of surgical intervention for p-stage IIIA (N2) non-small cell lung cancer: acceptable prognosis predicted by complete resection in patients with single N2 disease with primary tumor in the upper lobe

OBJECTIVES

Non-small cell lung cancer with mediastinal lymph node involvement is a heterogeneous entity different from single mediastinal lymph node metastasis to multiple nodes or extranodal disease. The objective of this study was to identify the subpopulation of patients with N2 disease who can benefit from surgical intervention.

METHODS

We reviewed 219 consecutive patients with N2 non-small cell lung cancer treated with a thoracotomy between November 1980 and June 2002 and retrospectively analyzed 154 of those who had p-stage IIIA disease and underwent a complete resection. Age, sex, side (right or left), histology, location (upper or middle-lower lobe), tumor size, c-N factor, and N2 level (single or multiple) were used as prognostic variables.

RESULTS

The 3- and 5-year survivals were 45.3% and 28.1%, respectively, in patients with p-stage IIIA (N2) disease. Survival for those with single N2 non-small cell lung cancer was significantly better than in those with multiple N2 disease (P =.0001), and patients with a tumor in the upper lobe showed a significantly longer survival than those with middle-lower lobe involvement (P =.0467). The 3- and 5-year survivals for patients with single N2 disease with a primary tumor in the upper lobe were 74.9% and 53.5%, respectively. A multivariate analysis with Cox regression identified 5 predictors of better prognosis: younger age, squamous cell carcinoma as determined by histology, primary tumor location in the upper lobe, c-N0 status, and a single station of mediastinal node metastasis.

CONCLUSION

Our results suggest that of the heterogeneity of N2 diseases, patients with single N2 disease with non-small cell lung cancer in the upper lobe are good candidates for pulmonary resection.