Fig. 2

Kaplan-Meier estimates of the progression-free survival (PFS) of subgroup analysis. a Metastatic de-novo versus metastatic recurrent. The median PFS was 11.0 months (95%CI: 8.1–13.9 months) in patients with metastatic recurrent, and the median PFS was 4.0 months (95%CI: 2.0–6.0 months) in patients with metastatic de-novo. b No prior chemotherapy versus after chemotherapy. The median PFS was 9.5 months (95%CI: 6.5–12.5 months) in patients with no primary chemotherapy, and the median PFS was 10.5 months (95%CI: 6.1–13.9 months) in patients after chemotherapy. c Visceral metastasis versus non-visceral metastasis. The median PFS was 10.0 months (95%CI: 7.1–12.9 months) in patients with visceral metastasis, and the median PFS was 5.0 months (95%CI: 1.2–8.8 months) in patients without visceral metastasis. d Luminal type versus triple negative breast cancer. The median PFS was 9.0 months (95%CI: 6.4–11.6 months) in patients with luminal type, and the median PFS was 10.0 months (95%CI: 4.1–15.9 months) in patients without triple negative breast cancer. There were no significant differences between patients with and without prior chemotherapy (p = 0.784), visceral metastasis (p = 0.254) or subtype (p = 0.609), however, the PFS was significantly shorter in patients with metastatic de-novo than that in patients with metastatic recurrent (p = 0.007)