Re-appraisal of N2 disease by lymphatic drainage pattern for non-small-cell lung cancers: by terms of nodal stations, zones, chains, and a composite

A Comprehensive Comparison of Different Nodal Subclassification Methods in Surgically Resected Non-Small-Cell Lung Cancer Patients

INTRODUCTION

The revision of the N descriptor in non-small-cell lung cancer has been widely discussed in the past few years. Many different subclassification methods based on number or location of lymph nodes have been proposed for better distinguishing different N patients. This study aimed to systematically collect them and provide a comprehensive comparison among different subclassification methods in a large cohort.

METHOD

Pathological N1 or N2 non-small-cell lung cancer patients undergoing surgical resection between 2005 and 2016 in the Western China Lung Cancer Database were retrospectively reviewed. A literature review was conducted to collect previous subclassification methods. Kaplan-Meier and multivariable Cox analyses were used to examine the prognostic performance of subclassification methods. Decision curve analysis, Akaike's information criterion, and area under the receiver operating curve concordance were also performed to evaluate the standardized net benefit of the subclassification methods.

RESULTS

A total of 1625 patients were identified in our cohort. Eight subclassification methods were collected from previous articles and further grouped into subclassification based on number categories (node number or station number), location categories (lymph node zone or chain) or combination of number and location categories. Subclassification based on combination of lymph node location and number tended to have better discrimination ability in multivariable Cox analysis. No significant superiority among the different subclassification methods was observed in the three statistical models.

CONCLUSION

Subclassification based on the combination of location and number could be used to provide a more accurate prognostic stratification in surgically resected NSCLC and is worth further validation.

Spanish Lung Cancer Group SCAT trial: surgical audit to lymph node assessment based on IASLC recommendations

Background

The Spanish Customized Adjuvant Therapy (SCAT) trial assessed the role of individualized adjuvant therapy in clinical N0 incidental pN1 and/or N2 non-small cell lung cancer (NSCLC) completely resected. We assessed surgical topics with an in-depth analysis of quality of lymphadenectomy based on International Association for the Study of Lung Cancer (IASLC) recommendations.

Methods

Patients with information about lymphadenectomy available were included (N=451). Prospectively collected data about tumor, type of resection, and postoperative morbidity and quality of lymph node dissection (LND) were retrospectively evaluated. Role of lymph node assessment on survival was analyzed using Kaplan-Meier curves, using regression models to identify prognostic factors.

Results

In 33.7%, 17.7% and 49.9% of cases, regions 7, 10 and 11 respectively were not assessed. In 21.1% of patients, less than three lymph node regions were biopsied, while in 19.6% of patients less than six lymph nodes were assessed. In 53,4% of patients only one N1 region was evaluated. From patients with positive N2, 8.9% had no N1 regions biopsied. Twenty-nine percent of patients with at least one N2 lymph node resected shown the highest region involved. Thirty-day postoperative mortality was unknown. Five-year overall survival (OS) was 61.7% (95% CI: 55.4-67.4%), 51.5% (95% CI: 39.2-62.4%) and 42.3% (95% CI: 32.1-52.2%) for patients with N1, N2 and N1+N2 disease, respectively (P<0.01). Both number of lymph nodes resected and number of lymph nodes involved by tumor were significantly related to prognosis.

Conclusions

IASLC recommendations for surgical resections were not followed in a high proportion of surgical procedures. Hilar and mediastinal lymph node assessment and involvement showed to impact prognosis. Surgical issues such as postoperative mortality could not be evaluated owing to trial design.

Alternative methods of lymph node staging in lung cancer: a narrative review

The nodal status indicator in non-small cell lung cancer is one of the most crucial prognostic factors available. However, there are still many arguments among scientists regarding whether the currently used nodal status descriptor should be changed in the forthcoming editions of the Tumor Node Metastasis classification or whether it is precise enough and should be maintained as is. We reviewed studies concerning nodal factor classifications to evaluate their accuracy in non-small cell lung cancer patients and to address the previously mentioned challenge. We reviewed the PubMed database regarding the following classifications: ongoing 8^th edition of the Tumor Node Metastasis classification, number of positive lymph nodes, number of negative lymph nodes, number of dissected lymph nodes, lymph node ratio, nodal chains, log odds of positive lymph nodes, zone-based classification and one that is based on the number of lymph node stations involved. Moreover, we analysed data regarding various combinations of these classifications. Our analysis showed that the present nodal staging may not accurately categorize every lung cancer patient. The number of positive lymph nodes and lymph node ratio or the log odds of positive lymph nodes (as the mathematical modification of lymph node ratio) are more legitimate, as they possess very robust data and should be considered initially as additional factors that can be incorporated in ongoing nodal staging systems. Forthcoming non-small cell lung cancer staging systems could benefit from the addition of quantitative-based parameters. Additionally, the minimal extent of lymphadenectomy should be established as staging benefits from it. International, prospective validation studies need to be performed to optimize the cut-off values and prognostic groups and to confirm the superiority of the newly suggested descriptors in non-small cell lung cancer nodal staging.

Numbers and Stations: Impact of Examined Lymph Node on Precise Staging and Survival of Radiologically Pure-Solid NSCLC: A Multi-Institutional Study

Objectives

To determine the optimal number of examined lymph nodes (ELNs) and examined node stations (ENSs) in patients with radiologically pure-solid NSCLC and to investigate the impact of ELNs and ENSs on accurate staging and long-term survival.

Methods

Data from six institutions in the People’s Republic of China on resected c-stage Ⅰ to Ⅱ NSCLCs presenting as pure-solid tumors were analyzed for the impact of ELNs and ENSs on nodal upstaging, stage migration, recurrence-free survival, and overall survival by using multivariate models. The correlations between different end points and ELNs or ENSs were fitted with a smoother (using Locally Weighted Scatterplot Smoothing tool), and the structural break points were determined by the Chow test.

Results

Both ELNs and ENSs were identified as prognostic factors for overall survival (ENS: hazard ratio [HR], 0.697; 95% confidence interval [CI]: 0.590–0.824; p < 0.001; ELN: HR, 0.945; 95% CI: 0.909–0.983; p = 0.005) and recurrence-free survival (ENS: HR, 0.863; 95% CI: 0.791–0.941; p = 0.001; ELN: HR, 0.960; 95% CI: 0.938–0.981; p < 0.001). Intraoperative ELNs and ENSs were found to be associated with postoperative nodal upstaging. Cut point analysis revealed an optimal cutoff of 16 LNs and five node stations for patients with c-stage Ⅰ to Ⅱ pure-solid NSCLCs, which were examined in our multi-institutional cohort.

Conclusions

Both ELNs and ENSs are associated with more accurate node staging and better long-term survival. We recommend 16 LNs and five stations as the cut point for evaluating the quality of LN examination for c-stage Ⅰ to Ⅱ patients with radiologically pure-solid NSCLCs.

Proposal of a new nodal classification for operable non-small cell lung cancer based on the number of negative lymph nodes and the anatomical location of metastatic lymph nodes

Lymph node metastasis is one of the most important prognostic indicators in patients with radically resected non-small cell lung cancer (NSCLC). This retrospective study aimed to compare the predictive value of metastatic lymph nodes (MNs), lymph node ratio (LNR), resected lymph nodes (RNs), and negative lymph nodes (NNs) with the currently used pathologic nodal (pN) staging category.We conducted a retrospective analysis of 1019 consecutive NSCLC patients treated with complete resection in a single institution. Prognostic values of various lymph node factors were evaluated by analysis of univariate and multivariate Cox proportional hazards model, and the results were compared with those using the location-based pN stage classification.The median follow-up duration was 47 months. During this period, 353 cases of cancer recurrence and 337 deaths were reported. Multivariate cox analysis indicated that both pN and NN categories were independent predictors of patient survival. The patients were divided into six groups on the basis of pN and NN categories. The survival rates of the groups were as follows: pN0, NN≥8, 81.4%; pN0, NN<8, 73.8%; pN1, NN≥8, 61.4%; pN1, NN<8, 54.2%; pN2, NN≥8, 48.4%; and pN2>1, NN<8, 35.0%. Comparison of the predictive values of the lymph node factors showed that the new N category was a more valuable prognostic factor in operable NSCLC.The combination of anatomically based pN stage classification and the number of MNs is an accurate prognostic determinant in patients with operable NSCLC which can be equal to 8th N category.

Prognostic analysis of the bronchoplastic and broncho-arterioplastic lobectomy of non-small cell lung cancers-10-year experiences of 161 patients

BACKGROUND

Bronchoplastic and broncho-arterioplastic lobectomy is technically demanding. Present study performed a prognostic analysis of lobectomy patient based on 10-year data in a high-volume center.

METHODS

Overall, 161 non-small cell lung cancer (NSCLC) cases underwent bronchoplastic and broncho-arterioplastic lobectomy between January 2004 and November 2013. Follow-up information was obtained for 88.8% patients. Prognostic analysis was performed with the Cox proportional hazards model.

RESULTS

There were 133 bronchoplastic and 28 broncho-arterioplastic procedures. In detail, 97 sleeve and 64 wedge broncho-resection and reconstructions were conducted; pulmonary artery sleeve reconstructions were performed in 26 cases and tangential resection in 135 cases. 90-day post-operative mortality was 3.1% (5/161), and 24.8% (40/161) patients had post-operative complications. 5-year overall survival was 53.4% and 5-year disease-free survival (DFS) was 48.2% for the entire case series; these survival rates were 67.7% and 55.7% for stage I (n=31), 64.4% and 58.9% for stage II (n=62), and 36.9% and 31.9% for stage III disease, respectively. Univariate analysis revealed that age >65 and higher grade of pN were associated with worse overall survival while right side tumor, non-squamous histology type, and higher grade of pT and pN were associated with worse DFS. Multivariate analysis revealed that pN is the only independent factor of worse outcome.

CONCLUSIONS

Bronchoplastic and broncho-arterioplastic lobectomy are safe procedures for indicated NSCLC patients associated with a low rate of post-operative complications but favorable long-term survival. Recognition of prognostic factors helps improve outcomes for these patients.

The impact of positive nodal chain ratio on individualized multimodality therapy in non-small-cell lung cancer

This study aimed to analyze the prognostic significance of the positive nodal chain ratio (NCR) in non-small-cell lung cancer (NSCLC). A total of 208 pIIIa-N2 NSCLC patients who underwent complete surgical resections with a systematic nodal dissection were enrolled. The median values of NCR and the positive lymph node ratio (LNR) were used to grouping patients. The differences of overall survival (OS) and disease-free survival (DFS) between the different groups were compared. The median values of NCR and LNR were 0.31 and 0.45, respectively. The patients were separated into group A (NCR ≤0.45 and LNR ≤0.31; 91 cases), group B (NCR ≤0.45 and LNR >0.31 or NCR >0.45 and LNR ≤0.31; 51 cases), and group C (NCR >0.45 and LNR >0.31; 66 cases) according to their combined LCR and LNR values. Groups A, B, and C exhibited significantly different prognoses (5-year OS: 43.7, 25.2, and 12.3 %, respectively, p < 0.0001; 5-year DFS: 30.4, 23.3, and 8.6 %, respectively, p < 0.0001). Multivariate analyses revealed that this novel grouping method based on the combination of NCR and LNR was an independent prognostic factor for 5-year OS and 5-year DFS in pIIIa-N2 NSCLC. In group C, patients who received no postoperative treatment, adjuvant chemotherapy alone, or chemoradiotherapy exhibited different 5-year OS rates (0.0, 11.6, and 37.5 %, respectively, p = 0.003) and 5-year DFS rates (0.0, 7.5, and 25.0 %, respectively, p = 0.009). Therefore, postoperative chemoradiotherapy may significantly improve the prognosis of patients displaying NCR >0.45 and LNR >0.31. NCR combined with LNR may be more effective to guide individualized multimodality therapy including postoperative chemoradiotherapy for pIIIa-N2 NSCLC.

Selective mediastinal lymphadenectomy without intraoperative frozen section examinations for clinical stage I non-small-cell lung cancer: retrospective study of 403 cases

OBJECTIVE

The extent of mediastinal lymphadenectomy for clinical stage I non-small-cell lung cancer (NSCLC) remains controversial. This study explored the value of selective mediastinal lymphadenectomy from the clinical viewpoint.

METHODS

From 2005 to 2008, a total of 403 patients diagnosed clinically as having stage I NSCLC underwent lobectomy and mediastinal lymph node dissection. Among them, 309 underwent complete mediastinal lymphadenectomy, and the other 94 underwent selective mediastinal lymphadenectomy. We compared the perioperative parameters and overall survival statistics for the two groups retrospectively.

RESULTS

The two groups had no significant differences in sex, pathology, tumor location, or preoperative staging. The selective mediastinal lymphadenectomy group had an older average age, with a much higher rate of patients >70 years of age (p = 0.016). Also, the patients were apt to undergo thoracoscopic lobectomy (p = 0.044). This group had shorter operating times and less intraoperative bleeding. No significant differences in total drainage volume, length of hospital stay, or complication rates were found between the two groups. The mean follow-up periods were 35.8 ± 13.7 vs. 34.6 ± 17.2 months. Local and distant recurrence rates were 25.6 % vs. 30.9 %, respectively (p = 0.560). The 3-year and 5-year overall survival rates were 83.0 % and 74.6 % vs. 75.1 % and 68.5 %, respectively (p = 0.216).

CONCLUSIONS

For patients with clinical stage I NSCLC, selective mediastinal lymphadenectomy can reduce the trauma caused by the procedure, especially for elderly patients and those with co-morbidities. Survival was acceptable and was no worse than that after complete mediastinal lymphadenectomy. Our results need to be confirmed by prospective randomized controlled studies.

Prognostic role of station 3A mediastinal nodes for non-small-cell lung cancers

OBJECTIVES

Station 3A nodes have been commonly neglected in surgical practice. This retrospective study collected information on the incidence and risk factors of Station 3A node to ascertain the prognostic role of 3A nodal involvement.

METHODS

A total of 180 consecutive pN2 (stage IIIa) non-small-cell lung cancer (NSCLC) cases who underwent systemic lymphadenectomy and contained Station 3A nodes were enrolled. Survival rates were calculated according to the final pathology of Station 3A lymph node: Station 3A node (+) and Station 3A node (-). Statistical analysis was conducted using Kaplan-Meier and Cox regression models.

RESULTS

Station 3A nodal metastasis was validated in 32 cases, and the incidence of Station 3A node involvement was 17.8%. Station 3A nodes involvement was strongly associated with the metastatic status of Station 4R nodes and histological nature of pulmonary cancer. The overall 3-year survival was 53% and median survival time was 40.6 months. The 3-year survival difference was significant between Station 3A node (-) and Station 3A node (+) (63 vs 22%, χ(2) = 16.426, P < 0.001). Moreover, the overall 3-year survival was closely related with the number of involved nodal zones (χ(2) = 31.156, P < 0.001). Multivariate analysis showed two statistically significant risk factors for survival including metastasis of Station 3A node and the number of positive nodal zones (hazard ratios [HR]: 2.702; 95% confidence intervals [CI]: 1.008-7.242; P = 0.027; and HR: 7.404; 95% CI: 3.263-16.936, P < 0.001, respectively).

CONCLUSIONS

The involvement of Station 3A lymph nodes predicts poor prognosis of right-sided stage pIIIa-N2 NSCLC patients. Therefore, systemic lymphadenectomy for right-sided cancers should include Station 3A nodes when ascertaining a complete resection.

High dose involved field radiation therapy as salvage for loco-regional recurrence of non-small cell lung cancer

PURPOSE

To determine the effectiveness of salvage radiation therapy (RT) in patients with loco-regional recurrences (LRR) following initial complete resection of non-small cell lung cancer (NSCLC) and assess prognostic factors affecting survivals.

MATERIALS AND METHODS

Between 1994 and 2007, 64 patients with LRR after surgery of NSCLC were treated with high dose RT alone (78.1%) or concurrent chemo-radiation therapy (CCRT, 21.9%) at Samsung Medical Center. Twenty-nine patients (45.3%) had local recurrence, 26 patients (40.6%) had regional recurrence and 9 patients (14.1%) had recurrence of both components. The median RT dose was 54 Gy (range, 44-66 Gy). The radiation target volume included the recurrent lesions only.

RESULTS

The median follow-up time from the start of RT in survivors was 32.0 months. The rates of in-field failure free survival, intra-thoracic failure free survival and extra-thoracic failure free survival at 2 years were 52.3%, 33.9% and 59.4%, respectively. The median survival after RT was 18.5 months, and 2-year overall survival (OS) rate was 47.9%. On both univariate and multivariate analysis, the interval from surgery till recurrence and CCRT were significant prognostic factors for OS.

CONCLUSION

The current study demonstrates that involved field salvage RT is effective for LRR of NSCLC following surgery.

Survival impact of node zone classification in resected pathological N2 non-small cell lung cancer

We assessed the prognostic value of the 'Zone-classification' which has been proposed by the Japanese Association for Lung Cancer (JALC) for mediastinal nodal metastases in non-small cell lung cancer (NSCLC). Among 357 NSCLC patients who underwent curative surgery, 46 patients with pathological (p) N2 disease were divided into two groups as follows: 32 patients in whom the nearer zone was involved were classified as the pN2a-1 group, and 14 patients in whom the further mediastinal node station was involved were classified as the pN2a-2 group. The proportions of patients with non-adenocarcinoma histology, with multiple station metastases with the involvement of four or more nodes, and who underwent pneumonectomy, were higher in the pN2a-2 group. The 'Zone-classification' proved to be a significant prognostic factor in a univariate analysis (the 5-year overall survival rate, 7.1% for pN2a-2 versus 21.9% for pN2a-1; P < 0.01). A multivariate analysis confirmed that pN2a-2 sub-classification (hazard ratio 2.77; P = 0.03) and undergoing pneumonectomy (hazard ratio 4.86; P < 0.01) were independent and significant factors in predicting a poor prognosis. In pN2 NSCLC patients, the involved mediastinal zone according to the primary tumour site was important in prediction of survival.