Objective  To examine the variation in prognosis based on metastatic sites in patients with advanced small cell lung cancer (SCLC) and advanced non-small cell lung cancer (NSCLC).

  Methods  In total, 541 patients diagnosed either with advanced SCLC between January 2012 and December 2017 or advanced NSCLC between January 2015 and December 2017 in Tianjin Medical University Cancer Institute and Hospital were included in this retrospective study. The primary endpoint was overall survival (OS).

  Results  In SCLC, patients with single-site metastasis had better prognosis than those with multi-site metastases (P=0.000 4). However, there was no significant difference in OS between single-site metastasis and multi-site metastases in NSCLC (P=0.451). Among SCLC patients with single-site metastasis, brain metastases represented the best prognosismedian survival time (MST), 14.5 months, while bone metastases and liver metastases represented the second worst (MST, 11.5 months) and worst (MST, 10.3 months) prognoses, respectively. However, in NSCLC with single-site metastasis, lung metastases revealed the best prognosis (MST, not reached), while liver metastases (MST, 7.6 months) and adrenal metastases (MST, 7.3 months) revealed the poorest prognosis. Among SCLC patients with multi-site metastases, bone metastases (P=0.046) and liver metastases (P=0.019) showed poor prognosis, while brain (P=0.995), lung (P=0.847), and adrenal (P=0.255) metastases showed no significant effect on prognosis. Meanwhile, among NSCLC patients with multi-site metastases, brain metastases (P=0.054) and adrenal metastases (P=0.006) resulted in poor prognosis, while lung metastases (P=0.008) resulted in a better prognosis. However, the presence of bone (P=0.091) and liver metastases (P=0.300) showed no significant effect on prognosis in NSCLC patients with multi-site metastases.

  Conclusions  Differential prognostic significance was observed in site-specific metastases in SCLC and NSCLC.