P1.08-060 Survival of Patients with Unsuspected N2 (Stage IIIA) Non-Small Cell Lung Cancer

Abstract

There are few studies evaluating the N2 pattern and outcomes when a patient with non–small cell lung cancer (NSCLC) unexpectedly is found to have N2 disease at the time of thoracoscopy or thoracotomy. The objective of this study was to determine the survival of patients who have completely resected, nonsmall-cell, stage IIIA, lung cancer from unsuspected (nonimaged) N2 disease. A retrospective review of NSCLC patients treated with lobectomy for clinically unsuspected mediastinal nodal disease (cT1-cT3 cN0-cN1, pN2 disease) at our institution between January 2008 and December 2011 was conducted. All patients underwent computed tomography scan with contrast, R0 resection with complete thoracic lymphadenectomy, and had unsuspected, pathologic N2 NSCLC. Positron emission tomography scan or invasive staging was added in the attending physician’s choice. Unsuspected pN2 disease was found in 10.9% of patients (31 out of 284) who underwent lobectomy as primary therapy for cT1-cT3 cN0-cN1 NSCLC. Of these, cN0pN2 and cN1pN2 were 9.6% (26 out of 270) and 35% (5 out of 14), respectively. Compare to cN0 group, unsuspected pN2 was more frequent in the cN1group (p=.0023). In terms of the pattern of metastasis, multiple and single pN2 was observed similarly in cN0 and cN1 group (p=.9484). The 5-year overall survival of the entire unsuspected pN2 was 68.5%, and cN0pN2 cohort tended to have better prognosis than cN1pN2 cohort (71.1% (cN0pN2) vs. 50.0% (cN1pN2); p=.0898). No significant difference in 5y-OS between unsuspected single and multiple pN2 could be seen; (70.5% (single) vs. 66.7% (multiple); p=.07803). This analysis suggests that, in the setting of unsuspected pN2 NSCLC, proceeding with anatomic surgery does not appear to compromise outcomes. As unsuspected pN2 disease was more frequent in cN1 cohort and revealed poor prognosis, perioperative invasive mediastinal staging and additional therapy should be considered.