Demographic and clinical characteristics of the NSCLC patients.

<p>Abbreviations: ECOG, Eastern Cooperative Oncology Group; SD, stand deviation.</p><p>*<i>P</i> values refer to the comparison between early stage patients with surgery and advanced patients with chemotherapy. Student's t-test was used to compare age as a continuous variable; chi-square test was used to compare categorical variables, except for ECOG performance status, where Fisher's exact test was used.</p>†<p>Comparisons between never smokers and ever smokers.