Although patients with stage IV non-small cell lung cancer areknown to have a poor prognosis, the prognostic factors for survival have not been well evaluated. Such factors may be different from those for overall survival. This study was performed to analyze the prognostic factors for survival and the variation of survival according to metastatic organ, in patients with stage IV non-small cell lung cancer.

From January 1997 to December 2000, 151 patients with confirmed stage IV non-small cell lung cancer were enrolled into this study retrospectively. The clinical and laboratory data were analyzed using univariate Kaplan-Meier and Multivariate Cox regression models.

On univariate analysis, age, performance status, serum albumin level, weight loss, forced expiratory volume in one second (FEV1), systemic chemotherapy, the number of metastatic organs and serum lactate dehydrogenase (LDH) level were significant factors (p<0.05). In multivariate analysis, important factors for survival were ECOG performance (relative risk of death [RR]: 2.709), systemic chemotherapy (RR: 1.944), serum LDH level (RR: 1.819) and FEV1 (RR: 1.774) (p<0.05). Metastasis to the brain and liver was also a significant factor on univariate analysis). The presence of single lung metastasis was associated with better survival than that of other metastatic organs (p=0.000).

We confirmed that performance status and systemic chemotherapy were independent prognostic factors, as has been recognized. The survival of stage IV non-small cell lung cancer patients was different according to the metastatic organs. Among the metastatic sites, only patients with metastasis to the lung showed better survival than that of other sites, while metastasis of the brain or liver was associated with worse survival than that of other sites.