Important factors for achieving survival of five years or more in non-small cell lung cancer patients with distant metastasis

In order to examine which factors were important for achieving a ≥5 year survival time in non-small cell lung cancer (NSCLC) patients with distant metastasis, 268 NSCLC patients who received first-line chemotherapy between January 2004 and December 2007 were retrospectively examined. The median survival time of the patients was 14 months, with 22 surviving for ≥5 years, 48 for ≥2 years, but <5 years, and 198 surviving <2 years. Multivariate analysis determined that never having smoked, a good performance status, relapse following thoracic surgery and intra-thoracic metastasis were significantly favorable prognostic factors, while abdominal metastasis was a significantly poor prognostic factor. The ≥5 years and ≥2–5 years groups had significantly more favorable prognostic factors than the <2 years group. The never-smoked status was a particularly important factor for ≥5 years of survival. The ≥5 years and ≥2–5 years groups achieved a significantly more favorable response to first-line chemotherapy, and a greater number of regimens, total months of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) treatment and cytotoxic agent treatment cycles compared with the <2 years group. In total, ~50% of the patients received palliative radiotherapy. In the ≥5 years group, patients with EGFR drug-sensitive mutations achieved ≥5 years of survival mainly by EGFR-TKI therapy, while those without EGFR mutations achieved ≥5 years of survival by continuing effective cytotoxic agents. Achievement of >5 years of survival was found to correlate with the presence of favorable prognostic factors, response to first-line chemotherapy, provision of appropriate EGFR-TKI therapy according to genetic testing results, continuing effective cytotoxic regimens and the use of radiotherapy as local therapy.