Original article
General thoracic
Risk Factors for Occult Mediastinal Metastases in Clinical Stage I Non-Small Cell Lung Cancer

Presented at the Poster Session of the Forty-third Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 29–31, 2007.
https://doi.org/10.1016/j.athoracsur.2007.03.081Get rights and content

Background

In patients deemed to have clinical stage I for non-small cell lung cancer (NSCLC) after computerized tomography (CT) and positron emission tomography (PET) scans, the utility of mediastinoscopy to detect occult mediastinal metastases is unclear. The goal of this study was to analyze the risk factors for occult mediastinal metastases in this subset of patients.

Methods

We conducted a retrospective review during a 7-year period to identify patients with potentially operable clinical stage I NSCLC screened by CT and PET scans. Medical records were reviewed, and the prevalence of pathologic N2 disease was analyzed according to clinical tumor location, size, histology, and PET uptake of the primary tumor.

Results

Of 224 patients identified with clinical stage I NSCLC with a CT-negative and PET-negative mediastinum, 16 patients had pathologic N2 disease proven by mediastinoscopy (n = 11) or after resection (n = 5). The overall prevalence of histologically confirmed N2 disease was 6.5% in clinical T1 patients and 8.7% in clinical T2 patients. Central tumors had a higher prevalence of N2 disease compared with peripheral tumors, 21.6% versus 2.9% (p < 0.001). Larger clinical T size predicted a higher prevalence of occult N2 disease (p < 0.001). All 16 patients with occult N2 metastases had adenocarcinoma as the primary tumor cell type. When the PET maximum standardized uptake value (SUVmax) of the primary tumors was analyzed, patients with occult N2 metastases had a higher median SUVmax of the primary tumor compared with patients without N2 metastases, 6.0 g/mL versus 3.6 g/mL (p = 0.017).

Conclusions

For patients deemed at clinical stage I NSCLC by CT and PET, the prevalence of missed N2 metastases increased significantly with larger tumor size and central location. Adenocarcinoma cell type and a high PET SUVmax of the primary tumor were other risk factors. Mediastinoscopy may have improved yield in the select subset of patients with one or more risk factor.

Section snippets

Material and Methods

We conducted a retrospective review of an institutional review board–approved prospective database to identify patients with potentially operable clinical stage I NSCLC with a CT-negative and PET-negative mediastinum from January 2000 to November 2006. This study was approved by the institutional review board of the Weill Medical College of Cornell University, and patient consent was waived. Patients were excluded if both PET and chest CT had not been performed. A total of 224 patients were

Clinical Findings

During the study period from January 2000 to November 2006, 224 patients (87 men, 137 women) were identified. Their median age was 69.5 years (range, 45 to 90 years). All patients were deemed to have clinical stage I NSCLC after radiologic assessments by CT of the chest and upper abdomen (including the adrenals), PET scanning, and any other appropriate imaging modalities including CT or magnetic resonance imaging of the brain. Cervical mediastinoscopies were done in 76 patients (34%), and 11

Comment

The diagnosis of bronchogenic carcinoma carries a dismal prognosis for most patients. The stage of carcinoma at diagnosis remains one of the most important determinants of survival in NSCLC, with earlier stage patients having a better chance of long-term survival [10]. For patients with resectable stage I disease, 5-year survival can be as high as 80% [11]. Patients with metastatic involvement of mediastinal lymph nodes have poor survival, however, and should not be offered surgical resection

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