Lymph node stage may provide important prognostic information related to survival for patients with non-small cell lung cancer (NSCLC), according to a study published in the Journal of Thoracic Oncology.
Guidelines for TNM staging of NSCLC recently included M1a as a category for stage IV classification. M1a disease is defined as metastases within the chest cavity, including pleural dissemination, pericardial dissemination, and contralateral pulmonary nodules. However, while the lymph node metastasis (N) is an important prognostic factor and determinant of stage in M0 patients, its clinical importance among patients with M1a disease has not been exclusively evaluated and warrants further exploration.
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For that reason, researchers led by, Chenyang Dai, MD, Shanghai Pulmonary Hospital, China, selected 39,731 patients with M1a NSCLC from the Surveillance, Epidemiology, and End Results database between January 2005 and December 2012 to see how lung cancer-specific survival (LCSS) was affected by N stage. A Cox proportional hazards regression model and statistical analyses were used to evaluate prognostic factors and compare patient subgroups.
Results of the study demonstrated that M1a patients without lymph node involvement had the longest LCSS, followed by patients with N1 disease (metastasis in ipsilateral peribronchial, perihilar and intrapulmonary lymph nodes). There was no significant difference in LCSS between patients with N2 or N3 disease. Findings were similar when patients were dived into two temporal cohorts (2005-2008 and 2009-2012), as well as when M1a patients were subdivided into contralateral pulmonary nodules and pleural dissemination, which did show a slight difference in LCSS between N2 and N3 among patients with malignant pleural nodules.
Multivariate analyses confirmed lymph node involvement as an independent prognostic factor for patients with M1a NSCLC, and this result was present in all patient subgroups.
Thus, researchers concluded that lymph node stage may have clinical significance among patients with NSCLC and M1a disease.
