Background: It is well known that more than 40% patients were initially diagnosed with advanced non-small cell lung cancer (NSCLC) with intrapulmonary or/and distant metastasis. However, up to now, the reports about effects of different metastatic sites on survival were limited. The aim of this study is to investigate the clinicopathologic and survival difference by retrospective analysis among sole intrapulmonary metastasis, sole extrathoracic distant metastasis and simultaneous metastasis of lung and other extrathoracic organs for the patients with advanced NSCLC, and to analyze the prognosis-related factors of NSCLC with intrapulmonary metastasis.
Methods: Of the 425 patients with stage IV NSCLC diagnosed by pathology and through staging evaluation and treated at Beijing Cancer Hospital with long follow-up during Oct. 1995 to Dec. 2003, 81 cases had sole intrapulmonary metastasis, 98 cases had sole extrathoracic distant metastasis and 68 cases presented simultaneous lung metastasis and extrathoracic spread. Kaplan-Meier survival curve was performed to estimate the survival of patients with different metastasis, Log-Rank test was used to compare their survival difference, and univariate analysis was used to find prognostic related factors.
Results: Median survival time (MST) and 1-, 2-, 3-year survival rate (SR) for patients with sole intrapulmonary metastasis were 13 months (95% CI: 11-15), 57%, 21%, 7%, respectively; MST was 22 months (95% CI: 18-26) for patients with N1 and/or N2 and 10 months (95%CI: 7-13) for patients with N3 (P=0.001). Among the patients with ipsilateral, contralateral and bilateral intrapulmonary metastasis, difference of MST and 1-, 2-, 3-year SR had no statistical significance (P > 0.05); Survival of patients with sole intrapulmonary metastasis was not significantly different from that of patients with sole brain or bone metastasis (P > 0.05), but was longer than that of patients with simultaneous lung and extrathoracic spread (P=0.021). One way analysis of variance showed that no significant association were found among age, pathologic subtype, differentiation degree or response of first-line chemotherapy and survival of the patients with sole intrapulmonary metastasis (P > 0.05), but sex and invasive status of lymph node (N1/N2 vs N3) were found to influence the survival of the patients (P= 0.018, P=0.001). Further stratified analysis by age showed that invasion of lymph node was independent prognostic factor (P=0.002); whereas for the patients with simultaneous metastasis of lung and distant organs, metastatic numbers (2 vs ≥3) of organ were independent prognostic factor (P=0.013).
Conclusions: No statistical difference is found among survival of NSCLC patients with sole intrapulmonary metastasis and with sole brain, bone metastasis. Invasive status of lymph node and metastatic number of organ are important prognostic factors for patients with sole intrapulmonary metastasis and simultaneous metastasis of lung and extrathoracic organs, respectively.