Surgical assessment and intraoperative management of mediastinal lymph nodes in non-small cell lung cancer

Effect of selective lymph node dissection based on patterns of lobe-specific lymph node metastases on patient outcome in patients with resectable non-small cell lung cancer: a large-scale retrospective cohort study applying a propensity score

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.

Surgery for early-stage non-small cell lung cancer: a systematic review of the video-assisted thoracoscopic surgery versus thoracotomy approaches to lobectomy

Video-assisted thoracoscopic surgery (VATS) for lobectomy has been touted to provide superior outcomes, compared with thoracotomy, for patients with early-stage non-small-cell lung cancer (NSCLC). However, supporting data are limited to case series and small observational studies. We hypothesized that a systematic review of the literature would enable a more objective evaluation of the evidence in order to determine the potential superiority of the VATS approach, compared with thoracotomy, in terms of short-term morbidity and long-term survival. To identify relevant articles for inclusion in our analysis, we performed a systematic review of the MEDLINE database. We looked for randomized controlled trials, observational studies, and case series that reported outcomes after VATS or thoracotomy lobectomy for NSCLC. For statistical testing, we used a two-sided approach (alpha = 0.05) under the hypothesis that VATS lobectomy is superior to thoracotomy lobectomy. We screened 17,923 studies. After independent review of the abstracts by 2 reviewers, we included 39 studies (only one randomized controlled trial) in our analysis. In aggregate, these 39 studies involved 3256 thoracotomy and 3114 VATS patients. The characteristics of the two groups were not significantly different. Compared with thoracotomy, VATS lobectomy was associated with shorter chest tube duration, shorter length of hospital stay, and improved survival (at 4 years after resection), all statistically significant. Compared with lobectomy performed by thoracotomy, VATS lobectomy for patients with early-stage NSCLC is appears to favor lower morbidity and improved survival rates.

[Role of mediastinoscopy and repeat mediastinoscopy today]

For patients with lung cancer preoperative evaluation of the mediastinal lymph nodes is important to estimate local operability and/or to consider the necessity of neoadjuvant treatment. Cervical mediastinoscopy is generally accepted as a safe and highly accurate procedure in the staging of lung cancer. Nodes accessible to CM are the levels of the superior (level 2R and 2L) and inferior (level 4R and 4L) paratracheal and subcarinal (level 7) nodal stations. Additionally extended CM and left parasternal mediastinotomy allow the exploration of the aortopulmonary window (level 5) and anterior mediastinal nodes (level 6). In locally advanced lung cancer repeat mediastinoscopy was used after induction chemotherapy or chemoradiation to reexplore the upper mediastinum in order to select patients with a higher probability to undergo complete resection. Operative mortality of both investigations is less than 0.5%; the preoperative complication rate is very low (less than 4%). Because of the higher sensitivity, specificity, and accuracy, mediastinoscopy and repeat mediastinoscopy are superior to new methods like FDG-PET, FDG-PET/CT, EBUS-FNA, and EUS-FNA.

A novel approach to positron emission tomography in lung cancer

18F-fluorodeoxyglucose positron emission tomography-computed tomography is integral to the staging of lung cancer. We describe the combined use of diagnostic preoperative 18F-fluorodeoxyglucose positron emission tomography-computed tomography, intraoperative 18F-fluorodeoxyglucose handheld gamma probe detection, and immediate postoperative 18F-fluorodeoxyglucose positron emission tomography-computed tomography patient and specimen imaging for improved staging and determination of adequacy of mediastinal lymph node dissection.

Complete mediastinal lymphadenectomy: the core component of the multidisciplinary therapy in resectable non-small cell lung cancer

There is a great deal of concern about metastasis of lung cancer to regional lymph nodes, due partly to the work of groups of thoracic surgeons in Japan and North America beginning in the 1970s. The classification of regional lymph node stations for lung cancer staging published by Mountain and Dresler has been widely adopted for more than ten years. Anatomic landmarks for 14 levels of intrapulmonary, hilar, and mediastinal lymph nodes stations are designated. Skip transfer and occult lymph node metastasis, confirmed by studies regarding the mode of spread of intrathoracic lymphatic metastasis, are two theoretical bases for complete mediastinal lymphadenectomy of lung cancer. However, whether or not the degree of the dissection influences prognosis, the role of systematic nodal dissection (SND) vs mediastinal lymph node sampling (MLD) in resectable non-small cell lung cancer (NSCLC) remains controversial. A systematic literature search was performed to identify relevant reports, making full use of the 'Cited by,' 'Related Records,' 'References,' and 'Author Index' functions in the PubMed and ISI Web of Science databases. This paper presents a review of the role of mediastinal lymph node distribution and methods of determining suitability for hilar and mediastinal lymphadenectomy based on the four subsets of stage IIIA-N2, balancing the cost vs effect of mediastinal lymph node dissection in resectable NSCLC, focusing on the stage migration bias in clinical trials comparing SND and MLS, recommending a reasonable node dissection sequence, improving the prospects for the perioperative anti-tumor therapy based on mediastinal lymphadenectomy, and evaluating the various preoperative staging techniques. Finally, we believe that, besides the role of complete resection and accurate staging, the complete mediastinal lymphadenectomy is the core component of the lung cancer multidisciplinary therapy, and suggest that the values of lymphadenectomy should be further assessed using decision-tree analysis based on large-scale prospective randomized trials and pooled analysis to evaluate the costs vs effects.