Search

Objective: Lobectomy with systematic complete mediastinal lymph node dissection is standard surgical treatment for localized non-small cell lung cancer. However, selective mediastinal lymph node dissection based on lobe-specific metastases (selective dissection) has often been performed. This study was designed to evaluate the validity of the selective lymph node dissection., Methods: From 1995 through 2003, 625 patients in our hospital had surgery for complete mediastinal lymph node dissection and 147 for selective dissection. We evaluated whether selective dissection adversely affected overall survival. To minimize possible biases due to confounding by treatment indication, we performed a retrospective cohort analysis by applying a propensity score. The propensity score was calculated by logistic regression based on 15 factors available that were potentially associated with treatment indication. Patients were divided into 4 groups according to quartile, and comparison between selective dissection and complete mediastinal lymph node dissection was made using propensity score quartile-stratified Cox proportional hazard models., Results: Comparison of baseline characteristics between patients having selective dissection and patients having complete mediastinal lymph node dissection according to propensity score quartile supported comparability of the 2 groups. The 5-year overall survival rates were 76.0% for selective dissection versus 71.9% for complete mediastinal lymph node dissection. The 5-year survival probabilities stratified by propensity score quartile consistently showed no marked difference. In multivariate models, there was no significant difference between the 2 groups (hazard ratio = 1.17, P = .500) as also seen in the analysis without propensity score (hazard ratio = 1.06; 95% confidence interval, 0.68-1.64; P = .810). Therefore, selective dissection showed no significant impact on poor survival compared with complete mediastinal lymph node dissection., Conclusions: Selective lymph node dissection did not worsen the survival of patients with non-small cell lung cancer., (Copyright 2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: The TNM classification has been widely used as a guide for estimating prognosis and is the basis for treatment decisions on various solid tumors. The International Association for the Study of Lung Cancer Staging Committee has proposed a new staging system for the next revision scheduled in 2009. However, its validity has not been established fully. Here we assessed its utilities and drawbacks., Methods: We reviewed 1556 consecutive patients with non-small cell lung cancers who underwent pulmonary resection in our institution and reviewed their survival characteristics based on the 2009 system compared with the current (1997) system., Results: The numbers of patients with stage IIA disease increased remarkably when using the 2009 system because of the reclassification of stages IB and IIB. Although the 5-year survival rates of the patients with stage IB and IIA disease in the 1997 system showed no difference with the 2009 system, the survival rates of patients with stage IB disease was 68.0%, which is better than that of patients with stage IIA disease (57.6%). The patient survival curves showed stepwise deterioration as the numbers increased, except for patient with stage IV disease., Conclusions: Our study supported the proposal for this new staging system. Compared with the 1997 system, the 2009 system appears to be superior in separating stage IB and IIA disease and provides an even distribution among the stage groupings, although it is slightly complicated. The survival characteristics of 1556 resected cases in this single Japanese institution validated the proposed 2009 system.

Objectives: Second primary lung cancers are prevalent after treatment for initial lung cancer, and the lung is also one of the most frequent sites for recurrence after removal of early-stage lung cancer. The objective of the present study is to clarify the clonal origin of the second tumor with the p53 gene mutation used as a clonal marker., Methods: Of 794 consecutive patients who underwent pulmonary resection for primary lung cancer from 1980 to 1993, 22 required second pulmonary resection during the follow-up period, with a median interval of 38 months. We examined 16 of these patients for mutations of the p53 gene occurring in exons 5 through 8 by the polymerase chain reaction/single strand conformation polymorphism method. Differential diagnosis was also made on a morphologic basis, considering the degree of cellular differentiation and cytologic subtypes., Results: Nine of the 16 patients analyzed had at least one p53 mutation in their tumors. We were thus able to make molecular diagnoses for these patients. The mutational status of the p53 gene was discordant in all nine patients, suggesting a different clonal origin despite the fact that six of them had almost identical histologic features., Conclusions: Analysis of p53 gene mutations was thus useful in distinguishing second primary lung cancers from recurrent tumors. The observed heterogeneity of p53 status was also in line with the "field cancerization" concept.