Prognostic relevance of regional lymph-node distribution in patients with N1-positive non-small cell lung cancer: A retrospective single-center analysis.

OBJECTIVE: Lymph node (LN) metastases predict survival in patients with non-small cell lung cancer (NSCLC) treated with curative surgery. Nevertheless, prognostic differences within the same nodal (N) status have been reported. Consequently, the International Association for the Study of Lung Cancer (IASLC) proposed to stratify patients with limited nodal disease (pN1) from low (pN1a) to high (pN1b) nodal tumor burden. This study aimed to validate the IASLC proposal in a large single-center surgical cohort of patients with pN1 NSCLC. MATERIAL AND METHODS: Data from 317 patients with pN1 NSCLC treated between January 2012 and December 2016, were retrospectively analyzed. Associations between distribution of LN metastases and survival were analyzed for different classification models-toward nodal extension (pN1a: one station involved; pN1b: multiple stations involved) and toward location (pN1 in the hilar [LN#10/11] or peripheral zone [LN#12-14]). RESULTS: Tumor-specific survival (TSS) in the entire pN1 cohort was 67.1% at five years. Five-year TSS rates for pN1a and pN1b patients were comparable (67.6% vs. 66.5%, p = 0.623). Significant survival differences from pN1a to pN1b were observed only in patients with adenocarcinoma histology and completed adjuvant chemotherapy (5-year TSS: pN1a, 80.4% vs. pN1b, 49.6%; p = 0.005). TSS for LN metastases in the hilar zone/peripheral zone or in both zones was 68.2% and 59.9%, respectively (p = 0.068). In multivariate analysis, adjuvant chemotherapy, squamous cell histology, and nodal disease limited to one zone nodal disease were identified as independent beneficial prognostic factors (p < 0.05). CONCLUSION: pN1 in only one region (hilar or lobar) was associated with better outcome than metastatic affection of both regions after surgery and adjuvant therapy. A stratification towards single (pN1a) and multiple (pN1b) N1-metastases was found of prognostic relevance only in adenocarcinoma. Prospective multicenter analysis of prognostic subgroups in N1 NSCLC is required to evaluate its clinical impact for consideration in future TNM classification.

Value of systematic mediastinal lymph node dissection during pulmonary metastasectomy.

BACKGROUND: Systematic mediastinal lymph node dissection is the accepted standard when curative resection of bronchial carcinoma is performed. However, mediastinal lymph node dissection is not routinely performed with pulmonary metastasectomy, in which only enlarged or suspicious lymph nodes are removed. The incidence of malignant infiltration of mediastinal lymph nodes in patients with pulmonary metastases is not known. METHODS: Sixty-three patients who underwent 71 resections through a thoracotomy for pulmonary metastases of different primary tumors were studied prospectively. Selected patients showed no evidence of tumor progression or extrathoracic metastases and pulmonary metastasectomy was planned with curative intent. All patients underwent preoperative helical computed tomography (CT) scanning. Only patients with no evidence of suspicious mediastinal lymph nodes on the CT scan (less than 1 cm in the short axis) were included in this study. A mediastinal lymph node dissection was performed routinely with metastasectomy. RESULTS: In 9 patients (14.3%) at least one mediastinal lymph node revealed malignant cells in accordance with the resected metastases. When compared with the preoperative CT scan, additional pulmonary metastases were detected in 16.9% of performed operations. There was a trend toward an improved survival rate in patients without involvement of the mediastinal lymph nodes. The number of pulmonary metastases had no influence on survival. CONCLUSIONS: On a patient-by-patient basis, the frequency of misdiagnosed mediastinal lymph node metastases is about the same as compared with non-small cell bronchial carcinomas. Systematic mediastinal lymph node dissection reveals a significant number of patients, who otherwise are assumed free of residual tumor. The knowledge of metastases to mediastinal lymph nodes after complete resection of pulmonary metastases could influence the decision for adjuvant therapy in selected cases.