Occult Micrometastases in N2 Lymph Nodes of Stage 1 NSCLC Linked to Decreased Overall Survival
Presence of occult micrometastases by immunohistochemistry staining in N2 lymph nodes was linked to decreased overall survival.
The presence of occult micrometastases (OM) by immunohistochemistry (IHC) staining in N2 lymph nodes of patients with stage 1 non-small cell lung cancer (NSCLC) was linked to decreased overall survival, according to a study published in the Journal of Clinical Oncology.1
The Cancer and Leukemia Group B 9761 conducted a prospectively designed study to determine the prognostic significance of OM because undetected OM could potentially be a prognostic indicator of outcomes following resection of stage 1 NSCLC.
A total of 502 patients with suspected clinical stage 1 (T1-2N0M0) NSCLC were enrolled in the study. Molecular analysis was performed on primary tumor sites and lymph nodes. Both were assayed for OM using IHC for cytokeratin and real-time reverse transcriptase polymerase chain reaction (PCR) for carcinoembryonic antigen.
Of the 502 patients, 498 underwent complete surgical staging. Results showed that 304 patients (61%) had pathologic stage 1 NSCLC (T1, 58%; T2, 42%) and were included in the final analysis.
IHC was used to analyze lymph nodes from 298 patients: 41 (14%) were IHC-positive (42% in N1 position; 58% in N2 position). IHC-positivity was not linked to overall survival or disease-free survival. Patients whose IHC-positive lymph nodes were in the N2 position had statistically significantly worse survival rates (HR, 2.04; P = .017).
RELATED: Docetaxel Plus Ramucirumab May Be Effective for Urothelial Carcinoma
Real-time reverse transcriptase-PCR was used to analyze lymph nodes from 256 patients: 176 (69%) were PCR-positive (52% in N1 position; 48% in N2 position). PCR-positivity was not associated with overall survival or disease-free survival.
- Martin LW, D'Cunha J, Wang X, et al. Detection of occult micrometastases in patients with clinical stage I non-small-cell lung cancer: a prospective analysis of mature results of CALGB 9761 (Alliance) [published online ahead of print February 29, 2016]. J Clin Oncol. doi: 10.1200/JCO.2015.63.4543.