Nodal involvement pattern in resectable lung cancer according to tumor location

Non-Lobe Specific Metastases in Occult N2 after Lobectomy for Clinical N0 Non-Small Cell Lung Cancer

OBJECTIVES

Non-small cell lung cancer can spread into lobe specific stations and non-lobe-specific mediastinal lymph nodes. We evaluated frequency and features of non-lobe specific nodal metastases, focusing especially on the prognostic value of only non-lobe specific N2-metastases after lobectomy.

METHODS

We performed a retrospective review of 550 patients with non-small cell lung cancer with clinical N0, undergoing lobectomy and systematic or lobe specific node dissection. We evaluated disease free and overall survival rates using Kaplan-Meier method and significance was tested by log-rank test.

RESULT

Occult N2 disease was detected in 68 patients (8.1%), 26 of them (38.2%) had metastases in non-lobe specific stations. Comparing patients with lobe and non-lobe specific lymph node metastases, 3-years DFS rate was 44.4% vs. 20.0% (p-value = 0.009), while 3-years OS rate was 87.3% vs. 26.7% (p-value <0.001). Among patients with non-lobe specific metastases 16 of them (61.5%) had only non-lobe specific metastases, the remaining 10 patients (38.5%) had metastatic lymph node at the same time in non-lobe specific station but also in lobe-specific stations. Comparing post-operative survival between patients with only non-lobe specific metastases and synchronous lobe and non-lobe specific metastases, 3-years DFS rate was 12.5% vs. 41.3% respectively (p-value = 0.03), and 3-years OS rate was 12.5% vs 76.7% (p-value = 0.002).

CONCLUSION

In patients with occult N2 disease, the finding of a metastatic lymph node in a non-lobe specific station relates with significant lower survival rate. The subset of patients who presented only non-lobe specific node metastases showed a significant lower survival rate compared to the remaining occult N2.

Nodal Involvement Pattern in Clinical Stage IA Non-Small Cell Lung Cancer According to Tumor Location

PURPOSE

The purpose of this study was to investigate lymph node involvement pattern in clinical stage IA non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

Clinical stage ⅠA NSCLC patients who underwent lobectomy and lymph node resection were included in this retrospective study. Mediastinal lymph node involvement was distinguished by different lobes and tumor size.

RESULTS

From 2000 to 2015, a total of 759 patients were identified: 282 (37.2%) with tumors in the right upper lobe (RUL), 183 (24.1%) in the left upper lobe (LUL), 124 (16.3%) in the right lower lobe (RLL), 103 (13.6%) in the left lower lobe (LLL), and 67 (8.8%) in the right middle lobe (RML). Patients with tumor size ≤1 cm accounted for 19.6%, >1 and ≤2 cm for 47.8%, >2 and ≤3 cm for 32.5%. Patients with pN1 accounted for 8.2%, and pN2 for 12.5%. Among patients with pN2, the inferior mediastinum was involved in 9.7% of RULs and 17.4% of LULs; the superior mediastinum was involved in 52.2% of RLLs and 36.4% of LLLs. Mediastinal lymph node metastasis was found in 13.2% of patients with size >1 and ≤2 cm, and 19.0% of >2 and ≤3 cm. Patients with tumors ≤1 cm had no N2 lymph node involved.

CONCLUSION

Selective lymph node dissection based on tumor location is not recommended in clinical stage ⅠA NSCLC, and systemic lymph node dissection should be performed for NSCLC with size >1 cm.

Lung Adenocarcinoma has a Higher Risk of Lymph Node Metastasis than Squamous Cell Carcinoma: A Propensity Score-Matched Analysis

BACKGROUND

Controversy still exists in which subtype of non-small-cell lung cancer [squamous cell carcinoma (SCC) or adenocarcinoma] is more likely to have lymph node (LN) metastasis. The aim of this study is to compare the pattern of LN metastasis in two cohorts of matched patients surgically treated for SCC or adenocarcinoma.

METHODS

A retrospective analysis of patients undergoing lobectomy or segmentectomy with systematic lymphadenectomy without preoperative treatment for lung SCC or adenocarcinoma was conducted in this study. Data for analysis consisted of age, gender, tumor size, lobe-specific tumor location, tumor location (peripheral or central), and pathologic findings. We conducted the propensity score-matched (PSM) analysis to eliminate potential bias effects of possible confounding factors.

RESULTS

From January 2015 to December 2016 in our department, we finally included a total of 387 patients (including 63 patients with SCC and 324 patients with adenocarcinoma) for analysis. For the unmatched cohort, there was no sufficient evidence of significantly different number of positive LNs (P = 0.90) and rate of LN metastasis (P = 0.23) between SCC patients and adenocarcinoma patients. However, potential confounding factors, for example gender, tumor size, tumor location, tumor differentiation, and total number of dissected LNs, were significantly different between patients with SCC and those with adenocarcinoma. In the analysis of matched cohort after PSM analysis, those above confounding factors were comparable between the two groups. However, patients with adenocarcinoma had significantly more mean positive LNs (2.2 and 0.7; P = 0.008) and a higher rate of LN metastasis (53% and 29%; P = 0.016) than those with SCC.

CONCLUSIONS

Lung adenocarcinoma had a higher risk of LN metastasis than SCC, suggesting that different therapeutic modalities may be indicated for the two different subtypes of lung cancer.

Lymph node metastasis outside of a tumor-bearing lobe in primary lung cancer and the status of interlobar fissures: The necessity for removing lymph nodes from an adjacent lobe

The new Tumor Node Metastasis staging system does not recognize fissure status with respect to adjacent lobe invasion (ALI) in lung cancer. Furthermore, no specific surgical strategies have been recommended for lymph node dissections around adjacent nontumor-bearing lobes (NTBLs) according to fissure status. Therefore, this study was undertaken to investigate the necessity of removing additional adjacent lobe lymph nodes in patients with nonsmall cell lung cancer (NSCLC) for lesions limited to in the vicinity of the interlobar fissure.From August 2013 to March 2015, the records of 332 patients, who underwent systematic mediastinal lymph node dissection, were reviewed in this retrospective study. The bronchial lymph nodes had been subjected to pathological examination, and the status of the fissures was also recorded. A statistical analysis was performed to identify the significant predictors of lymph node metastasis.The patients were divided into a nonadjacent lobe invasion (NALI) group (n = 295) and an ALI group (n = 37). There was a significant difference in tumors with pN2 disease between the ALI and NALI groups (37.8% vs 8.8%, P = .001). ALI tumors had significantly more frequent pleural involvement than NALI tumors (62.2% vs 43.1%, P = .035). The frequency of N2 involvement among tumors invading across the complete fissure was higher than that of the tumors invading across the incomplete fissure (44.4% vs 14.3%, P = .015). However, the frequency of N1 involvement among tumors invading across the incomplete fissure was not statistically different than that of tumors not invading across incomplete fissure (32.1% vs 24.2%, P = .357). Regarding lymph node metastasis in NTBL, 15 (12.7%) patients had lymph node metastases in NTBLs. Pleural involvement was an independent predictor of lymph node metastasis in an NTBL.A greater frequency of N2 lymph nodes existed in NSCLC with invading adjacent lobe across complete fissure, extensive lymphatic resection within the hilum, and NTBL in tumors with pleural involvement are justifiable and necessary.

Lymph node metastasis according to primary tumor location in T1 and T2 stage non-small cell lung cancer patients

BACKGROUND

To evaluate the pattern of lymph node metastasis (LNM) according to primary tumor location in T1 and T2 stage non-small cell lung cancer (NSCLC) patients.

METHODS

The data of 1916 NSCLC patients with LNM who underwent surgery with systematic nodal resection between November 2008 to December 2014 were included in the study. Analyses of tumor location, pathological T stage, and nodal metastasis were performed.

RESULTS

In T1a stage patients, superior mediastinum, aortopulmonary, and inferior mediastinum lymph node metastases were observed in primary tumors present in the right upper lobe (RUL), left upper lobe (LUL) and right middle lobe (RML), respectively. In T1b-stage patients, superior mediastinum, aortopulmonary, and inferior mediastinum lymph node metastases were observed in the RML, LUL, and right lower lobe (RLL), respectively. In patients with T2a-stage, superior mediastinum, aortopulmonary and inferior mediastinum lymph node metastases were observed in the RUL, LUL, and RLL, respectively. However, in T2b-stage patients, RUL, LUL and RML locations were associated with superior mediastinum, aortopulmonary, and inferior mediastinum lymph node metastases, respectively. Multivariable logistic regression showed that T stage was significantly associated with mediastinal and intrapulmonary lymph node metastases. In addition, tumor location was significantly associated with N2 station LNM.

CONCLUSION

LNM varied according to tumor location and T-stage, which are independent factors influencing N2 station LNM.

Risk factors for recurrence after complete resection of pathological stage N2 non-small cell lung cancer

Background

Tumor recurrence is the most common cause of treatment failure, especially after complete resection of pathological stage N2 non-small cell lung cancer (NSCLC). In this study, we investigated the clinicopathological characteristics in order to identify independent risk factors for postoperative recurrence.

Methods

Between January 2001 and December 2013, 96 patients who underwent surgical resection for pathological N2 NSCLC were retrospectively reviewed. Recurrence-free survival (RFS) was calculated by the Kaplan-Meier method to explore risk factors, while the Cox proportional hazard model was used to assess independent predictors.

Results

The median and five-year RFS rates were 15 months and 27.4%, respectively. Univariate analysis showed a significantly poorer prognosis for non-regional N2 metastasis, more than three metastatic N2 lymph nodes, multiple N2 station, and multiple N2 zone involvement. Multivariate analysis demonstrated that non-regional N2 metastasis (hazard ratio [HR] 1.857, 95% confidence interval [CI] 1.061–3.249, P = 0.030) and more than three metastatic N2 lymph nodes (HR 2.555, 95% CI 1.164–5.606, P = 0.019) were independent risk factors for RFS. Additionally, the incidence of non-regional N2 metastasis was higher in patients with a primary tumor in the left lower (57.1%) or right lower lobe (48.1%), followed by left upper (31.8%), right middle (14.3%) and right upper lobe (7.7%).

Conclusion

The combination of the distribution and number of metastatic N2 lymph nodes provides a more accurate prediction for N2 NSCLC regarding recurrence. Non-regional N2 metastasis could occur with a primary tumor in any lobe, but occurs more frequently in the lower lobe.